***Useful Information For The Working Sparky***

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Schedule of Inspections , page 340 ← ( 1 ) ( 2 ) in the making ,

Methods of Protection against Electric shock

Both basic & fault protection :

(i) Selv , ( Correctly Installed and used , Note 1 ●
(ii) Pelv , ( Same as Selv but with Earth , ←
(iii) Double Insulation , ( Protected by an layer of Insulation look for symbol , Note 2 ●
(iv) Reinforced insulation , ( Single layer of very strong insulation , Note 2 ●

Basic Protection , Note 3 ●

(i) Insulation of live parts ( All live parts Insulated where required , ←
(ii) Barriers or enclosures ( Correct IP codes . Check Definitions , ←
(iii) Obstacles ( Limited use Not Domestic , Note 4 ●
(iv) Placing out of reach ( 410-3-5 Note 5 ●

Fault Protection

(i) Automatic Disconnection of Supply ,

● Presence of Earthing Conductor , ( At intake , ←
● Presence of Circuit Protective Conductors , ( CPC in all Circuits , ←
● Presence of Protective Bonding Conductors’ , ( Water, Gas, Oil, etc , ←
● Presence of Supplementary Bonding Conductors , ( Mainly Bathrooms , ←
● Presence of Earthing Arrangements for Combined , ( Rare , ←
Protective and Functional Purposes ,

● Presence of Adequate Arrangement for ( Generators ←
Alternative Source(s) where Applicable

● Felv , ( Not Compliant with Selv , ← ●
● Choice and Setting of Protective and Monitoring ( Correct MCB or Fuse , ←
Devices ( for Fault and / or Overcurrrent Protection )

(ii) Non-Conducting Location , Note 6 ●
● Absence of Protective Conductors , ( Operating Theatres , ←

(iii) Earth-Free Local Equipotential Bonding , Note 6 ●
● Presence of Earth-Free Local Equipotential Bonding , ( Not Domestic ,

(iv) Electrical Separation , Note 7 ● ( Isolating Transformers , ← ●
Provided for one item of Current-Using Equipment ,

● Provided for More than One item of Current-Using Equipment ,

Additional Protection ,

● Presence of Residual Current Devices , ( 415 -1 ←
● Presence of Supplementary Bonding Conductors , ( 415-2 ←




(1) SELV - an Extra Low Voltage Systems which is Electrically Separated
From Earth and from Other Systems in Such a Way that a Single – Fault Cannot give Rise to the Risk of Electric Shock ,
The Particular Requirement of Regulations must be Checked ( see Section 414 )

(2) Double or Reinforced Insulation , Not Suitable for Domestic or Similar Installations if it is the Sole Protective Measure ( see 412-1-3 )

(3) Basic Protection – will Include Measurement of Distances where Appropriate ,

(4 ) Obstacles – only Adopted in Special Circumstances ( see 417-3 )

(5) Placing out of Reach – only Adopted in Special Circumstances ( see 417-3

(6) Non- Conducting Locations and Earth-Free Local Equipotential Bonding –
These are Not Recognised for General Application ,
May Only be used where the Installation is Controlled / Under the Supervision of Skilled or Instructed Persons ( see Section 418 )

(7) Electrical Separation – the Particular Requirements of the Regulations must be Checked if a Single item of Current-using Equipment is
Supplied from a Single Source , see Section 413, if More than One the Installation must be Controlled / under the Supervision of Skilled or
Instructed Persons , See Also Regulations 418-3




● IMD / 411.6.3 , Installed in a Location where Unskilled Personnel have Access shall be Designed or Installed in such a Way ,
Shall NOT be Possible to Modify the Settings , Except by Use of a Key, or a Tool or a Password ,
● RCM / Doesn’t Trip , Gives Warning of Problems , Used with IT Systems ,
● RCDs Do Not Protect against Overloads / Do Not Protect against Short Currents , “ Definitions “ ● RCD Operation, Current Balance ) Earth Fault Current Only , “ Definitions “
● RCCBs Residual Current Circuit-Breaker with Integral Overcurrent Protection , ( Not for Overload Short-Circuit ) “ Definitions “
● RCBOs Minimise Inconvenience in the Event of a Fault / Short-Circuit , Overcurrent Protection , “ Definitions “
● RCBOs Both Overload Short-Circuit Protection / Overcurrent Protection : “ Definitions “

● Overload Current , Overcurrent Occurring in a Circuit which is Electrically Sound , 431.1.1 / 430.3 ,
● Preliminary Design ( In ≥ Ib ) 433 , ● Overcurrents Requirements’ ( In ≥ Ib ) 434 , Domestic Installation ,
Fault Currents’ ( Earth Faults or Shorts-Circuits )
Overload Currents , ( Overcurrents may be ! ,
Cables must be-Able to Carry Overcurrents Without Damage , (Iz) 411 ,
411 , Fault / Protection is Provided by ( i ) ( ii ) , “ADS”
( iii ) , Protection by One Device ,
Three Methods’ for Achieving “ Fault-Protection “ 131.2.2 , ( i ) ( ii ) , ( iii ) ,
Protection Against Electric Shock to be Provided by Basic & Fault Protection , ( one Method Common to Both )

 

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Functional Testing : all 3 is the same Meaning ,

RCDs used for “ Earth Fault “ Currents Only ( 30mA RCD is installed to give Added Protection Against “ Basic Protection “ i.e. , Touching Live Parts )
Breaker should Trip 0ut in 40mS at a Residual Operating Current of x5 , 150mS ,

● 30mA RCD is Used to Provide Supplementary Protection against Electric Shock .
When tested with a Current of 150mA , operating time should not exceed , 40mS

( 30mA RCD is Installed to give Added Protection )
Residual Operating Current of x5 , 150mS , 40mS

Schedule of Inspections , page 340 ← ( 2 )

Prevention of Mutual Detrimental Influence
● (a) Proximity of Non – Electrical Services and Other Influences , ( Cables tied to Pipes ? Hot Pipes near Cables ) ←

● (b) Segregation of Band I & Band II Circuits or use of Band II Insulation , ( Low and Extra Low Voltages Segregated ) ←

● (c) Segregation of Safety Circuits , ( Emergency Lighting and Fire Alarms Cables Not in Same Trunking ) ←

Identification ,

● (a) Presence of Diagrams , Instructions , Circuit Charts and Similar Information , ( At Mains ) ← “ Distribution Board Schedule “ Domestic ,

● (b) Presence of Danger Notices and Other Warning Notices , ( Bonding , Isolation ) ← 514-10

● (c) Labelling of Protective Devices , Switches & Terminals , ( What do they do ? ) ←

● (d) Identification of Conductors , ( Sleeving and Cores ) ← 514-4-2 / table, 51

Cables & Conductors

● Selection of Conductors for Current-Carrying Capacity & Voltage Drop , ( Measure or Calculate ) ←

● Erection Methods , ( Installed to BS-7671 ) ←

● Routing of Cables in Prescribed Zones , ( On-Site-Guide ) ←

● Cables Incorporating Earthed Armour or Sheath , or Run
Within An Earthed Wiring System , or Otherwise Adequately
Protected Against Nails , Screws & the Like , ( 522-6 ) ←

● Additional Protection Provided by 30mA RCD for Cables in
Concealed Walls ( where Required in Premises not Under the
Supervision of a Skilled or Instructed Person ) ( 411-3-3 / 522-6 ) ←

● Connection of Conductors , ( Tightn no Copper Showing ) ←

● Presence of Fire Barriers , Suitable Seals & Protection Against Thermal Effects , ( 527-1 ) ←

General

● Presence and Correct Location of Appropriate Devices for Isolation & Switching , ( Isolators in Place ) ←

● Adequacy of Access to Switchgear and Other Equipment , ( Safe Access ) ←

● Particular Protective Measures for Special Installations and Locations , ( Special Locations Part 7 What is Required ) ←

● Connection of single-Pole Device for Protection or Switching in ( Polarity Visual Check ) ←
Line Conductors Only

● Correct Connection of Accessories and Equipment ( As Instructions’ ) ←

● Presence of Undervoltage Protective Devices ( Motor Starters ) ←

● Selection of Equipment and Protective Measures Appropriate to External Influences , ( Water , Dust Proof ) ←

● Selection of Appropriate Functional Switching Devices , ( Isolator Not used as a Switch ) ←

Thank you , George is on the 6/Pack , Sorry did I mean 12 pack tonight , 21 Again ,

PS / Ill need to stop Studying or ILL end up a Masters Decree , Sorry about this Jason , can Keep a Good man Down Amberleaf ,


● A Good Insulator has Low Conductivity and ( High Resistivity ) ←

● 100mA RCD protecting a TT installation tested at ½ : ( Should Not Operate ) ←

● Testing a Ring Final Circuit Protected by a BS-EN 61009 30mA RCBO with an “ RCD tester “ at x5, should disconnect ( within 40mS ) ←

● An RCD when tested at 500% ( x5 times ) of its tripping rating should : ( trip within 40mS )

● When Tested a Ring Final Circuit Protected by 200mS BS-EN 61009 - 30mA RCBO

● Specification for Socket-Outlets Incorporating Residual Current Device ( S.R.C.D. s )
When tested at 100% an RCD Protecting Socket-Outlet to BS-7288 should Operate Within , 200mS
with an “ RCD Tester “ At x5 , should Disconnect ( Within 40mS )
BS-7288 – IP56 ↔ if Used Out Doors ,

● RCD , What is the Result of a very Low Total Fault Loop Impedance
( Very High Fault Current and Quick Disconnection ) ←

● Note that for RCD Protected Socket-Outlet to BS-7671 the RCD should Operate 200mS at I∆n ←←

● RCBOs to 61008 / 61009 should Operate Within 300mS
RCBOs should Operate , at Full I∆n they Operate within 300mS , and at x5 they should Operate within 40mS ,

● RCD Operating time at I∆n Must be Less than 300mS BS-EN Type ←←←← or 200mS if BS - ←←←←

● RCD Operating time at 5 I∆n Only Required for RCDs Rated at 30mA or Less ,
When used for “ Supplementary Protection “ against Direct Contact , Never Use RCD above 30mA ,

● Insulation Résistance , Values Required for between Live Conductors , and Live Conductors and Earth , if Measured Value is below 2MΩ ↔ Further Investigations is Required
● Damp Getting into a Cable “ Pyo ” can Lead ( Insulation Failure ) ←
( This can Lead to ” Nuisance Tripping ” of the Protective Device )
>> Never leave Pyo Exposed to Damp ‹‹‹ if you Do you’ll lose more the a Meter Cable and Look a right Pratt , PS , Electrician doing Handstands’

● When Carrying out an Insulation Resistance Test between Conductors on a One-Way Lighting Circuit , have the
( Remember Switch Closed and Lamp Out ) ↔ ( Two –Way / One Switch Closed / and the Other Opened )

● It is a Good idea when Performing an Insulation Resistance Test on a Large Installation to Subdivide Circuits’ ,
( To avoid False Readings from Parallel Resistance’s ) ←

● To Ensure the Protective Device Operates Requires a ( Low Fault Loop Impedance Path with a Resultant High Earth Fault Current Flow ) ←

● When a Periodic Inspection should be Carried Out are ,
When a Property is being Prepared to be Let ,
When a Property is being Sold where Tenets have Lived in Property
( Periodic Inspection Reports Should Only be Used for Reporting on the Condition of an Existing Installation , p-339
BS-7671 - p-339 – Notes (1)

 

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Overcurrent Protective Device for the Supply ,
Usually this will be a BS-88 or BS-1361 Cartridge Fuse and it will Normally be Marked on the Supply Cut Out
If it is Not , then it Should be Found by Asking the Supply Provider , ↔ PS , phones out Chaps ,
Domestic Electricians ↔ 100A , type IIb – BS-1361 415V a.c , ←←←
Type of Overcurrent Protective Device ,
BS- or BS-EN , enter Number ,

BS-88-2 50kA
BS-1361 16kA / 33kA
Type 1 rated Current 5 to 45A ,
Type 1 Fuses to BS 1361 / 41.2 ( Zs )
BS-1361 Type 1 Distribution boards , Replaced by Consumers ,
Type 11 rated 60A to 100A
Type 11 BS- 1362 , Primarily intended , Distributors Cut-Out Fuses Service Units Domestic Similar Premises ,

Fuses BS- 1362 , / 41.2 ( Zs ) cartridge Fuse , Regs P-229
Fuses BS- 1363 , / Pat Testing Insulation Resistance Test 1MΩ / 500v Domestic , Class 1 Equipment , Regs P-229 ,

Nature of Supply Boundary’s ,
This can be Gained by Enquiry or Measurement ,
U. is Phase to Phase / Phase
Uo Phase to Earth ,

Short Circuit Capacity ,
Short Circuit Capacity of the Device
It may be marked on the Device , if not ( OSG. 7.4 ) – p-57

Whatever it is , it must be at Least → EQUAL ← to the ( PFC ) ←←←

For Domestic Electricians ,

Method of Protection against Electric Shock ,
Both Basic & Fault Protection
SELV & PELV ( 414.1 / 414.4 ( SELV Source that a Shock to Earth Cannot Occur for a Single Fault , ←←←
Protection Against Both Direct & Indirect Contact is Afforded by Using SELV , ←←←

Basic Protection
Applies to all Electrical Installations , ( 412.2 ↔ Band 1 / 416.1

Barriers or Enclosures ,
Applies to all Electrical Installations , All Enclosures must Comply with 412.2.2.1
Horizontal top Surfaces to Enclosures IP4X sides ,
Front and Bottom IP2X or IPXXB ,

Blanks fitted to Distribution Units
Access to Live Parts by Use of key or Tool ,
Secondary barriers within Enclosures Only Removable with the Use of key or Tool ,

Double & Reinforced Insulation , ( Regulations 412.1

IMDs
411.6.3 the following Monitoring Devices & Protective Devices may be Used , 538.1.3 / 531.6.1

Placing Out of Reach
Applies to Overhead Lines , ( Regulations 410.3.5 & 417.1

Fault Protection
Automatic Disconnection of Supply
Requirements for Fault Protection are set Out in ( Regulations 411.3

Presence of Earthing Conductor
Protective Earthing must be present ( Regulations 411.3.1.1

Presence of Circuit Protective Conductor
Each Circuit must have a CPC which must be Tested for Continuity ,

Presence of Protective Bonding Conductors
Extraneous Parts of the Installation must be Connected to the Main Earthing Terminal ( MET ) Regulations 411.3.1.2

Presence of Supplementary Protective Bonding Conductors ( where Required )
Regulations 415.2 This is Used where Additional Protection Against Electric Shock , can be used in some Special Locations ,

FELV
41.7.1. This is Used where Extra Low Voltage is Required but it is not Necessary to Comply with the
Regulations of SELV or PELV ,

Choice and Setting of Protective and Monitoring Devices for Protection
Against Indirect Contact and / or Overcurrent ,
Correct Size and Type of Protective Devices / RCD are suitable for use to which they are being put,
Monitoring Devices not used for Domestic Situations ,
IT supply Systems / some Construction Sites ,

Non-Conducting Locations
Used in Special Areas / Hospitals / Laboratories
Installation Requires Specialist Knowledge ( Regulations 418.1 )

Earth Free Local Equipotential Bonding
Found in Electronic / Electronic / Electrical Repair Workshops ( Regulations 418.2. )

Electrical Separation
Used in Bathrooms’ for Saver Sockets , The Secondary Supply is Separated from Earth ,
This does Not include SELV ( Regulations 413.1

Where more than One item of Equipment is Supplied from a Single Source ,
( Regulations 418.3 Should be Applied ,

Prevention of Mutual Detrimental Influence
Proximity of Non Electrical Services and Other Influence’s
( Regulations 515.1 / 2 and Sections 522 and 528.3 Items should be inspected to Ensure that the Electrical System cannot cause
harm to Non - Electrical Services ,and that the Electrical System is Unaffected by External Influences ,
Cables tied to Pipes or Next to Central Heating Pipes ,

Segregation of Band I & Band II Circuits or Band II Insulation Used
( Regulations 515.2 Sec 528.1 Low Voltage Cables not in same Enclosures as Extra Low Voltage Cables
TV , Aerials , Door Bells & Telephone Cables ,

“ Domestic “ Electrician

● An Enclosure that would prevent Ingress by British Standards human Finger would have an IP rating of , ( IP2X ) ←

● the Top part of a Distribution Board must Conform to ( IP4X ) ← 416.2.2

● The Sides of a Distribution Board must Conform to ( IP2X ) ← 416.2.4

● A Code IP4X assigned to a Electrical Item would Prevent Ingress from ( Wire or Solid Objects Greater than 1mm in Diameter ) ←

● Protection Against Direct Contact by Barrier or an Enclosure : 416.2
● Provided During Erection 612. 4. 5
● IP2X ( IPXXB ) Protection Required for all Enclosures from , Side & Bottom ,
● IP2X ( IPXXB ) = No Solid Objects larger than 12mm Diameter and 80mm long ,
● Top Distribution Board ↔ IP4X Protection required for all enclosures from above ( max 1mm – dia )
● 10N Finger pressure Max ,
“ Test Finger ” Must be to BS-3042 Specification

● Guidance Note 1 , Selection & Erection ( Guidance Notes )
● Guidance Note 2 , Isolation & Switching , ( Guidance Notes )
● Guidance Note 3 , Inspection & Testing , ( Guidance Notes for BS-7671 )
● Guidance Note 4 , Protection from Fire , ( Guidance Notes for BS-7671 )
● Guidance Note 5 , Protection Against Electrical Shock , ( Guidance Notes for BS-7671 )
● Guidance Note 6 , Against Overcurrent , ( Guidance Notes for BS-7671 )
● Guidance Note 7 , Special Locations ( IEE Regulations )
● Guidance Note 8 , Earthing & Bonding ( Standards and Compliance )
● Guidance Note GS-38 , Electrical Equipment ,
“ GN-3 “

● ( Band I / 50V & Band II / 1000V - Definitions , p-31

The Frequency of Periodic , Inspecting & Testing and Test is Dependant on the Type of Installation ,
The Environment and the Type of Use ( BS-7671 Wiring Regulations ) “Construction Utilization and Environment this – App , 5 ( BS-7671

This comes under , Guidance Note 3
Periodic
It is Very Important that the Extent & Limitations of the Inspection and Test is Agreed with the Person Ordering
The Work before Commencing Work , ←←←

Before the Extent & Limitations can be Agreed , Discussion between ALL Parties Involved must take Place ,
The → ( Client ) ← will know why they want the Inspection Carried out & the Person who Carrying out the Inspection & Test should have
The Technical Knowledge and Experience to give the Correct Guidance ,

Remember this One , this mite Come up in the Future
This is one of many I was stung on .

 

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Observations & Recommendations’
Defects , if any Must be Recorded Accurately and Codes Given ,
Codes to Indicate the Level of Attention Required ,

Code 1 ,
Requires Urgent Attention ,
Anything which could Compromise the Safety of those using the Installation should be Entered here
This would include Lack of Earthing , Undersized Cables , Damaged Accessories , High Zs Values ,
It is up to the Inspector Carrying out the Inspector to make a Judgement

Code 2 ,
Requires Improvement ,
Defects which do Not Immediately cause the Installation to be Regarded as Unsafe but could be Problematic in the Future ,
This could be , Corrosion , Old Cables such as Lighting Cables with No CPC , Labels missing ,
It is up to the Inspector Carrying out the Inspection to make a Judgement

Code 3 ,
This Could be anything that the Inspector who is Carrying out the Inspection & Test is Concerned about ,
But which is Outside of the Agreed Extent of the Inspection ,
Maybe a Circuit which Cannot be Traced , or Instruments Values within the Required Parameters – Anything that Might cause Concern ,

Code 4 ,
Does Not Comply with BS-7671
As the Requirements’ of BS-7671 are Amended , Parts of the Installation which would have Complied when the Installation was New ,
May now Not Comply ,
This could be , Sockets-Outlets that could be used to Supply Portable Equipment Outdoors ,
Not Protected by RCD ,CPCs which have been Sleeved with Green Sleeving & Not Green / Yellow ,
Switch returns Not Identified on Older Installations ,

Responsibility of the Tester carrying out the Inspection to Decide on which Code ,
It is up to the Inspector Carrying out the Inspection to make a Judgement

Assessment

This will Either be Satisfactory or Unsatisfactory ,
If the Observation Area of the Form has any Defects Other than Code 4 ,
The Assessment Must be Unsatisfactory ,

Any Change of Environment , that may have an Effect on Installation ,
Earthing Arrangements
Bonding
Isolation
Age
Safety
Ware-Tear

City & Guilds 2392 – 10 level 2 Certificate
Fundamental Inspection , Testing & Initial Verification

Testing of Electrical Installations :
Continuity – Methods 1 and 2 ( Continuity ( Ω ) Current (A)
Insulation resistance test ( Insulation ( MΩ ) Voltage (V)
Earth Loop impedance ( Ω ) Fuse (A)
Prospective fault current ( Ief / Ia )
Guidance Note 3 ( Schedule of test results )

● When Two RCDs are Connected in Series , to provide Discrimination , the first RCD should be an S –Type , RCD with built in time Delay should Not be Used to Provide Personal Protection , ● For an Installation forming part of a TT systems , a 100mA RCD is generally Installed at the Origin . a Time- Delayed or 100mA “S –Type ( or selective ) device is Often Used to Permit Discrimination with a Downstream 100mA Device , ● where an RCD is fitted only because the Earth Loop Impedance is to High for Shock Protection to be Provided by an Overcurrent Device , TT Systems ,

“ Testing Polarity “
● Polarity Test is Carried out with a Loop Tester ( Polarity Test can Confirm Correct Connection of Conductors within an Edison
Screw Lamp 612.5.2 (ii)

● The Easiest Method of Confirming Polarity on a Standard Ring Final Socket Outlet Circuit would be during ,
( The Continuity of Ring Final Conductors Test ) ↔ “ Test Prior to the Installation Being Energized “

● The Easiest Method of Confirming Polarity on a Standard Lighting Circuit would be During ,
( The Continuity CPC Test ) ↔ “ Test Prior to the Installation Being Energized “

● When Conducting a Continuity of CPC test , what other Test can be Carried Out at the same time , on the same Circuit ,
using the same Test Instrument and Settings , ( Polarity ) ↔ “ Test Prior to the Installation Being Energized “

● A Polarity Test is Conducted to Verify that ,
( Every Protective and Single Pole Device is Connected in the Line Conductor Only ) 612.6 ,

● A Polarity Test should be carried out on New Installation , ( Before Installation has be Energised )

● A Polarity Test is Preformed on Edison Screw lampholders to , Ensure the Centre Contact is Connected to the Line Conductor (ii) 612.6

● The Outer Contact of a Centre-Contact ( ES ) Lampholder , must be Connected to the , ( Neutral Conductor ) (ii) 612.6

● Polarity Tests on Final Circuits are Usually Carried out , ( During the Protective Conductor Continuity Test ( R1 + R2 )

“ Testing Periodic “

● Person Responsible for Specifying the First Periodic Inspection on an Installation , ( The Person Responsible for the Design )

● Periodic Inspection Report “ Forms “ ,
( This Report is Intended to be Issued Only for the Purpose on Condition of Existing Electrical Installation ) p-339 ,

● BS-7671 does Not give Specific Details on the Frequency of Periodic Inspection & Testing of Domestic Installation , 622.1 ,
Guidance Note-3 ( Suggests Every 10 years or Every Change of Occupancy )

● A Prospective Fault Current would be Recorded on A , ( Periodic Inspection Report )

● When Carrying out a Periodic Inspection on a Public House , which one of the following would Not Determine the Extent and
Limitation of the Report , ( The Original Designer )

● A Periodic Inspection Report would be Carried out on , ( An Existing Property )

● During a Routine Periodic Inspection , the Person who Determines the time to the Next Periodic Inspection would be the ,
( Inspection & Tester )

“ What is a Polarity Test “

● Basically it is a Test that Creates a Circuit using the Phase Conductor and the Single Pole Device ,
Breaking the Circuit when Operating the Device ,
Means that the Reading on the Instrument will Change ,
Confirming that the Device must be Connected in the Phase Conductor ,

● Minor Works Certificate ,

May be used only for an Addition or Alteration to a Single Circuit that does NOT Extend to the Provision of a new Circuit ,
Appendix 6 , p-331 , (ii ) ( vi )

● On a Minor Certificate it is “ Necessary to Record ” , ( Prospective Fault Current )

● A Minor Works Certificate should Contain ( Earth Fault Loop Impedance )

● On a Minor Works Certificate it is “ Not Necessary “ to Record ( Ze )

● After Wiring an Additional light fitting into a New Conservatory by Extending from an Existing Circuit , on Completion you should Issue ,
( Minor Works Certificate ) ↔ PS this is Addition & Alteration to an Installation , Regs , p-336

● After Adding an Extra Socket in Bedroom vie a Spur off an Existing Socket , the Customer should be Provided with
( Minor Works Certificate ) ↔ PS this is Addition & Alteration to an Installation , Regs , p-336

● In a Mechanics Workshop , the Repositioning of an Emergency Stop Button would Require the Completion of ,
( Minor Works Certificate ) ↔ PS this is Addition & Alteration to an Installation , Regs , p-336

● Isolation at the Source of a 3-Phase 4 -Wire Installation and Forming Part of a TN System may be Provided by a
( Three Pole Manually Operated Switch )

● Discrimination Occurs when ( Only the Plug top fuse Operates when a Portable Appliance Develops a Fault )

● Which of the Following is “ Not “ Part of the Earth Fault Loop Impedance Path Within a TN-S Systems
( Neutral Conductor within the Consumers Installation )

● According to BS-7671 what Minimum Level of Fault Current will be Required to Operate a BS-1361 5A Fuse 0.2sec ( 25A )
Regs , fig, 31 – K1 / R1 , Phase Conductor

● in the Equation S = √ I2 x t / k what does the Symbol “ I “ Signify ( Circuit Fault Current )

● in the Equation what does the Symbol “ S “ Signify ( Required Minimum size of the CPC )

● A Short-Circuit Current is Defined as an Overcurrent Occurring in a Circuit when a ( Fault of Negligible Occurs
Between Phase & Neutral Conductors

 

[amberleaf]

● The Prospective Fault Current would be Recorded on a , Electrical Installation Certificate ,

● an Essential Test that would be Carried Out for a Minor Works Certificate would be , Socket Outlet Polarity ,

● Before Commencing the Inspection & Testing of a New Installation , Information you should have Available would be ,
External Loop Impedance ,

● Before Commencing the Inspection & Testing of a New Installation , Information you should have Available would be ,
Earthing Arrangement

● the Frequency of Periodic Inspections should be Determined by , the Type and use of Installation , the Frequency of
Maintenance and , the External Influences to which the Installation is Subjected ,

● After Installation of a New Shower in a Small Terraced House where there was Not one Previously ,
The Customer Should be Provided on Completion with , Electrical Installation Certificate ,

● When Performing an Earth Fault Loop Impedance Test , the Quick Method of Determining Compliance with BS-7671
Would be by Comparing the Results to , , Guidance Note 3 ,

● This is to Check on the Insulation Quality between Live Conductors’ and Live Conductors’ and Earth ,
● Mains must be Isolated for this test ,
● Instruments must generate a DC test voltage ↔ 500 volts
● Minimum acceptable Insulation resistance 61. p/158
● Caution must be Exercised when Conducting this Test ,

An Insulation Résistance Test is done to Establish the Insulations
An Insulation Résistance Test Establishes the ( Confirmed of the Cables )

The Electrical Separation of ELV and LV Circuits is Confirmed with an
● Insulation Résistance test ( ELV – LV – 500V dc )

In a Non-conducting location where the voltage does “ NOT “ Exceed 500 volts the Résistance of the Walls or Floors must Not be Less than
( The Résistance of the walls or floors must Not be Less than 418.1.5. (i) 50kΩ

In a Non-conducting location where the voltage “ Does “ Exceed 500 volts the Résistance of the Walls or Floors must Not be Less than
( The Résistance of the walls or floors must Not be Less than 418.1.5. (ii) 100kΩ

In a Non-conducting location , Insulation between any Extraneous Conductive parts
and Exposed Conductive parts is Tested at what Voltage
( Minimum Insulation Test voltage is 2000V , (iii ) 418.1.4

( 50V to 500V / 1.0MΩ ←
( SELV = 50v a.c / 250d.c ←

● Where the Circuit Includes Electronic Devices which are Likely to Influence the Result or be Damage ,
Only a Measurement between the Live Conductors Connected together and the Earthing Arrangements shall be Made ,
612.3.3

● Insulation Résistance shall be Measured between Live Conductors and between Live Conductors
And the Protective Conductor Connected to the Earthing Arrangement , Where Appropriate During this Measurement
Line & Neutral Conductors may be Connected Together ,
612.3.1 ( No Breakdown of the Conductor Insulation )

 

[fog]

Hi Amberleaf and many many thanks for brilliant information and the answer to many of my questions.

 

[amberleaf]

“ Electrical Certificate’s Issued ,

● The Prospective Fault Current would be Recorded on a , ( Electrical Installation Certificate ) ( PFC )

● A Prospective Fault Current would be Recorded on A , ( Periodic Inspection Report ) ( PFC )

● On a Minor Certificate it is “ Necessary to Record ” , ( Prospective Fault Current ) ( PFC )

“ Insulation Resistance Testing “
● Prior to performing an Insulation Resistance test , you should , ( Disconnect all Voltage Sensitive Devices )
● Prior to performing an Insulation Resistance test , you should , ( Ensure all Lamps are Removed )

● An Insulation Resistance Test on a Three Phase Installation can be more Easily Performed by ,
( Testing between Earth and all Live Conductors Connected together )

● According to BS-7671 17th Edition , the Minimum Insulation Resistance Value should be Investigated below , ( 2MΩ )

● Where the Circuit includes Electronic Devices which are likely to influence the Results or be Damaged ,
Only Measurement between the Live Conductors Connected together and the Earthing Arrangements shall be Made , 612.3.2

● It is a Good idea when Performing an Insulation Résistance Test on a Large Installation , To subdivide Circuits’ to avoid ,
( False Reading from Parallel Résistance )

● When an Insulation Résistance Test on a large Installation returns Unexpectedly Low readings , your course of action would be ,
To Individually Test each Circuit )

● Which Test is used to Prove that the Circuit under Tests has No Dangerous Short-Circuits Prior to the Circuit being Made “ Live ,
( Insulation Résistance ) ↔ This Test Verifies ( Proves ) that the Insulation of the Cables in good Order ,

● Which Test is Used to Prove that the Circuit Under Test has no Dangerous Short-Circuits Prior to the Circuit being Made Live
( Insulation Résistance ) “ Proves “ that the Insulation of the Cables in Good Working Order

● A Circuit Breaker for a Socket-Circuit is Tripping Intermittently , this Occurs even if there is Nothing Plugged in , the Likely Cause is ,
( Insulation Failure )

● Insulation Resistance Testers are Designed to Measure , ( High Résistance Using a dc voltage ) ←

● Damp Getting into a Cable can Lead to which Type of Fault , ( Insulation Failure ) ←
( This can Lead to ” Nuisance Tripping ” of the Protective Device )

● A Circuit Breaker for a Socket Circuit is Tripping Intermittently , This Occurs Evan if there is Nothing Plugged in ,
( The Likely Cause is , ( Insulation Failure )
( This would Match the Symptoms , it can be Caused by Overheating , Damp , or Mechanical Damage ,

● When Carrying out an Insulation Resistance Test between Conductors on a One-Way Lighting Circuit , have the
( Switch Closed and Lamp Out )

If an Additional Alternative has been Carried Out it Must Not ,
( Increase the Electrical Consumption )

610.2 The Result of the Assessment of the Fundamental Principles , Sec 131 ,
The Results of the Assessment of an Electrical Installation with Regards to Protection for Safety shall be Made Available to the ,
Together with the Information Required by Regulation 515.9.1 ( Inspector Prior to Carrying Out the Inspection and Test )

Information such as Diagrams and Schedules shall be made Available to the ,
( The Inspector Prior to Carrying out an Inspection and Test )

612.9 Earth Fault Loop Impedance

Where Protective Measures are Used which Require a Knowledge of “ Earth Fault Loop Impedance “ the Relevant Impedance Shall be Measured , or Determined by an Alternative Method ,
● Calculation ,
● Measurement

Before Inspecting the Condition of Electrical Equipment Installed in a New Unoccupied Building the Inspector Should
( Check for Components that may be Susceptible to Damage During Testing )

Any Addition to an Existing Installation Should ( Not Impair the Safety of the Existing Installation )
↔ ( Remember to Disconnect any Florescent Luminaries when Testing ) ↔

Which of the Following Duties is “ Not ” the Responsibility of the Inspector ( To Carry out Maintenance and Repairs on the Installation )

Records of Inspections and Test Results Should be Kept During the Life of an Installation , this will Enable ( Deterioration to be Identified )

According to BS-7671 No Additions or Alterations Should be Made to an Existing Installation Unless
( The Existing Installation Conforms to Current Regulations )

When Inspecting for Adequate Protection Against Direct Contact which of the following Does Not Require Inspection ,
Presence and Condition of , ( Connection of CPCs )

A Visual Inspection of a “ New “ Installation must be Carried Out ( During Erection and before Testing )

Which One of the Following Procedures would be Correct if Permission to Disconnect
Information Technology Equipment has “ Not “ been Received ( Do Not Apply Tests )

A Continuity Test at Each Socket-Outlet of a Ring Final Circuit is Carried Out to make sure that ( No Multiple Loop Exist )

When Carrying Out a Prospective Short Circuit Fault Current Test on a Three Phase System
The Approximate Fault Current between Phases Should be ,
( Double the Fault Current between One Phase and Neutral )

When Carrying Out a Prospective Short Circuit Current Fault Test on a Three Phase System the Approximate
Fault Current between Phases Should be ( PSCC ) Continuity of the Ring Final Circuit )

When Electrical Accessories have Neon Indictor Lamps Inaccurate Reading can Occur when Tests are
Carried Out to Determine the Resistance ( Insulation between Phase and Neutral )

A Legible Diagram , Chart or Table Relating to A Installation “ Must “ be Provided to Indicate
( Any Equipment Vulnerable to a Test )

What is the Maximum Earth Fault Loop Impedance Allowed when Using a 20A Type C Circuit Breaker
Giving a Disconnection Time of 5sec The Normal Voltage to Earth ( Uo ) is 55v = 0.28Ω Regulation’s , table 41.6 /

What is the Maximum Earth Fault Loop Impedance Allowed when Using a 20A Type BS-2-2 ( gG ) ↔ ( Motor Circuits Only )
Giving a Disconnection Time of 5sec The Normal Voltage to Earth ( Uo ) is 55v = 0.28Ω Regulation’s , table 41.6 /

The Commissioning Process take Place ( After an Installation has be Inspected & Tested )

Certification & Reporting
“ Before an Installation or Additions & Alterations to an Installation is Energised
Inspection & Testing Must be Carried Out to Ensure the
( Requirements of BS-7671 have Been Meet and an Appropriate Certificate Must then be Issued )

 

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This from the Red Book , 17th
1, Initial Inspection & Testing

Form ( 1 ) to ( 4 ) are Designed for Use when Inspecting & Testing a “ New Installation “
Or an Alteration or Addition to an Existing New Installation ( Form Comprise the Following )

1, Short form of Electrical Installation Certificate ( to be Used when One Person is Responsible for the Design )
Construction , Inspection & Testing of an Installation ,

2 , Electrical Installation Certificate ( Standards form from Appendix 6 / BS-7671

3 , Schedule of Inspections ,

4 , Schedule of Test Results ,

( “ Note on Completion and Guidance for Recipients are Provided with the Form )

2 , Minor Works ,

The Complete set of Forms for Initial Inspection & Testing may be Appropriate for Minor Works
When an Addition to an Electrical Installation does “ Not ” Extend to the Installation of a New Circuit
The Minor Works form may be Used , this form is Intended for such Work as the Addition of a New Socket-Outlet
Or Lighting Point to an Existing Circuit , or for Repair or Modification ,

Form ( 5 ) is the Minor Electrical Installation Works Certificate from Appendix 6 / BS-7671
( Notes on Completion and Guidance for Recipients are Provided with the Form )

3 , Periodic Inspection
Form ( 6 ) the Periodic Inspection Report from Appendix 6 of BS-7671 ,
Is Used when Carrying Out Routine Periodic Inspection & Testing of an Existing Installation ,
It is Not for Use when Alterations or Additions “ are Made A Schedule of Inspections ( 3 ) and Schedule of Test Results (4 ) should Accompany the Periodic Inspection Report ( 6 )

( “ Note on Completion and Guidance for Recipients are Provided with the Form )

During the Initial Verification of an Installation , which of the following forms Part of the Checklist ,
( Presence of Diagrams & Instructions’ ,

The Paperwork that Should be Issued on Completion of “ New “ Certificate ,
( Schedule of Test Results , Schedule of Inspection and an Electrical Installation Certificate ,

A Minor Work Certificate Should be Issued ,
( Where an Alteration “ Not” Requiring an Additional Circuit is Needed )

Periodic Inspection Report would be Carried Out on ,
( Existing Property )

The Person Responsible for Specifying the First Periodic Inspection on an Installations is ,
( The Person Responsible for the Design )

Segregation of Safety Circuits

Regulations 528.1 & 560.1
Fire Alarm , Emergency Lighting to be Segregated from each Other
And Other Circuits unless Wired in Cables with an Earthed Metal Sheath with an Insulated Covering ,
This could be Mineral Insulated Firetuff & FP200

Identification

Presence of Diagrams , Instructions , Circuit Charts & Similar Information
Regulations 514.9 & 560.7.9
Circuit charts , Plans , Past Inspection and Test Certificates and Schedules must be Available
For Domestic Installations , Circuit Identification would be a Minimum Requirement on an Older Installation ,

Presence of Danger Notices and Other Warning Notices
Regulations 514. Earth Bonding Labels ,
Voltage Warning , Isolation ,
Harmonization of Colours & RCD Testing are Common ,

Labelling of Protective Devices , Switches & Terminals
Regulations 514.1 & 514..8
Protective Devices Labelled ,
Conductors in Sequence ,
Switches & Isolators Marked to Identify the item they Control
If this is Not Obvious ,

Identification of Conductors
Regulations 514.3.1
Coloured Sleeve on Switch Wires or where Line Conductors’ are Not Clearly Identified ,

“ Statutory Regulations “ App-2 - 241

Regulation 28 of The Electricity Safety , Quality and Continuity Regulations 2002 ,
Requires Distributors’ to Provide the following Information to Relevant Persons Free of Charge ,

● The Maximum Prospective Short-Circuit Current at the Supply Terminals ,
● The Maximum Earth Loop Impedance of the Earth Fault Path Outside The Installation ( Ze )
● The Type and Rating of the Distributors’ Protective Device or Devices Nearest to the Supply Terminals ,
● The Type of Earthing System Applicable to the Connection ,
● The Number of Phases of the Supply ,
● The Frequency of the Supply and the Extent of the Permitted Variations ,
The Voltage of the Supply and the Extent of the Permitted Variations ,

543.4.1 Pen Conductors shall Not be Used within an Installation Except as Permitted by Regulation 543.4.2
In Great Britain , 8 (4 ) of the Electricity Safety , Quality and Continuity Regulations 2002 ,
Prohibits the Use of PEN Conductors in Consumer’s Installation ,
543.4.2
The Provisions of Regulations 543.4.3 / 543.4.9 may be Applied Only ,
(ii) Where the Installation is Supplied by a Privately Owned Transformer or Convertor ,
(iii) Where the Supply is Obtained from a Private Generating Plant ,

( Great Britain the Use of Combined Protective and Neutral ( PEN ) Conductors is Prohibited in Consumers Installations
One Exception , Supply Obtained from Private Generating Plant ,

IEE Guidance Note 3 Inspection & Testing
This Guidance Note is Part of a Series Issued by the IEE to give Specific Guidance The Inspection & Testing Procedure in a Simplified and Detailed Manner ,

Domestic Electricians
Electrical Installation Certificate Regulation BS-7671 p-334 Start There ,

The Electrical Installation Certificate is Used for the Initial Certification of a New Installation or for an Addition or Alteration
To an Existing Installation where New Circuits have be Introduced ,

The Certificate should be Accompanied by the Schedule(s) of Inspections and Schedule(s) of Test Results ,

The Electrical Installation Certificate should be Completed and Signed or Otherwise Authenticated by a Competent Person
( or Persons ) in Respect of the Design , Erection , Inspection & Testing of Work ,
If the Design , Construction and Testing is Carried Out by One Person a Single Signature Declaration may Replace the Three Signatures’ Required on the Certificate ,

Once Completed the Original Certificate and Schedules should be Given to the Person Ordering the Work
As Required by Regulation 632.3 BS-7671 : 2008 The Contractor should keep a Copy of the Certificate and Schedules ,

The Recommended time Interval before the First Periodic Inspection is Carried Out can
Be Obtained from the IEE Guidance Note 3

Once the Initial Periodic Inspection has been Carried Out the Next Periodic Inspection should take into Consideration
The Frequency and Quality of Maintenance the Installation is Expected to Receive During its Intended Life ,
The Period should then be Agreed between the Designer , Installer and any Other Relevant Body ,

Minor Electrical Installation Works Certificate

Minor Electrical Installation Works Certificate is Used as an Alternative to the Electrical Installation Certificate where the
Minor Electrical Installation Work is an Addition or Alteration that does Not Include the Provision of a New Circuit or Circuits

The Certificate may also be Used for the Replacement of Equipment such as Accessories & Luminaries ,
This does Not Extend to such things as Consumer Unit or Distribution Boards etc

Inspection , Testing and Certification should always be Carried Out Regardless of the Extent of the Work Undertaken ,

 

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The Electricity at Work Regulations apply to the Process of Inspection & Testing
The following Regulations are relevant to the Inspection and Testing Process for the Safety of Persons Carrying Out the Inspection & Testing

Regulation 3
Persons on Whom Duties are Imposed by these Regulations :
The Electricity at Work Regulations 1989 Apply to ;
(i) Employer e.g. Electrical Contractor ,
(ii) Employee e.g. Inspector ,
(iii) Self-Employed e.g. Electrician / Inspector ,

Regulation 4
Systems , Work Activities & Protective Equipment :
(i) Every Work Activity shall not Give rise to Danger e.g. Test Voltages
(ii) Any Personal Protective Equipment shall be Suitable , Maintained and Used Properly e.g. Hard Hat , ←

Regulation 5
Strength and Capability of Electrical Equipment ,
(i) No Electrical Equipment Shall be put into Use where its Strength and Capability may be Exceeded in such
A Way as May Give Rise to Danger e.g. Poorly Insulated Hand Tools & Test Equipment Not to GS-38 ( H.S.W.A ) ←

Regulation 6
Adverse or Hazardous Environment
(i) Electrical Equipment Exposed to Mechanical Damage , Weather , Natural Hazards’ , Temperature , Pressure ,
Water , Dirt , Dust , Corrosion , Flammable or Explosive Substances Shall be Suitable e.g. Test Instruments , ←

Regulation 7
Insulation , Protection and Placing of Conductors :
(i) All Conductors in a System which may Give Rise to Danger shall Either be Suitably Covered with Insulating Material
Or Suitably Placed e.g. Test Probes No More than 2mm ( Maximum 4mm ) ↔ Guidance Note GS-38 , Electrical Equipment ,

Regulation 8
Earthing or Other Suitable Precautions
(i) Precautions Shall be Taken Either by Earthing or Some Other Means to Prevent Danger Arising e.g.
Do Not Carry Out Live Tests such as External Loop Impedance ( Ze ) or Final Circuit Loop Impedance ( Zs )
With Earth Conductors Disconnected , ( Guidance Note 7 , Special Locations ( IEE Regulations )

Regulation 9
Integrity of Referenced Conductors
(i) if a Circuit Conductor is Connected to Earth or to Any Other Reference Point it Should Not Give Rise to Danger
If Disconnected e.g. Neutral Points which are Earthed as in TN-C / TN-C-S Systems should Not be Disconnected from their
Earth Terminal when Carrying Out Live testing as in Regulation ( 8 ) ←←

Regulation 10
Connections
(i) Where Necessary to Prevent Danger , Every Joint and Connection shall be Mechanically & Electrically Sound e.g.
Ensure all Connections are Tight when Carrying Out Functional Testing ,

Regulation 11
Means for Protecting from Excess of Current
(i) Effective Means , Suitable Located , shall be Provided for Preventing from Excess of Current Every Part of a System
As may be Necessary to Prevent Danger e.g. ↔ Do Not Replace or Link ( Short ) ↔ Out Fuses or Circuit Breakers During
Testing , Ensure Test Equipment has Suitable Protection such as Fused Test Leads ,

Regulation 12
Means for Cutting off the Supply and for Isolation
(i) Where Necessary to Prevent Danger , Suitable Means shall be Available for Cutting of the Supply e.g.
Tests such as Continuity of Protective Conductors and Insulation Résistance are Carried Out on Dead Installation or Circuits ,
It is Therefore Necessary to Carry Out a Safe Isolation Procedure Prior to Testing ,

Class 1 Equipment ( Exposed Metal Work Earthed )
Class 11 ( Separated Extra Low Voltage )
Class 111 Equipment ( SELV Supply )

( Assessment of General Characteristic would Include )
Maintainability , Safety Services and Continuity of Service
The Electricity at Work Regulations 1989
Require Every System to be Maintained such as to Prevent Danger
Consequently , all Installation Require Maintaining ,

Regulation 13
Precautions for Work on Equipment Made Dead
(i) Adequate Precautions shall be Taken to Prevent Electrical Equipment ,
Which has been Made Dead , in Order to Prevent Danger while Work is Carried Out on or Near that Equipment , from
Becoming Live e.g. Carry Out a Safe Isolation Procedure ,

Regulation 14
Work on or Near Live Conductors
(i) No Person shall be Engaged in any Work Activity on or Near any Live Conductors’ Unless it is Unreasonable for them to be Dead ,
It is Reasonable in All Circumstances or Suitable Precautions are Taken to Prevent Injury e.g.
Carry Out Safe Isolation Procedure ,

Regulation 15
Working Space , Access and Lighting
(i) For the Purpose of Enable Injury to be Prevented , Adequate Working Space ,Adequate Means of Access , and Adequate Lighting Shall be Provided at All Electrical Equipment in Circumstances which May Give Rise to Danger ,
e.g. Temporary Lighting

Regulation 16
Persons to be Competent To Prevent Danger & Injury
(i) No Person shall be Engaged in any Work Activity where Technical Knowledge or Experience is Necessary to Prevent Danger or ,
Where Appropriate , Injury , Unless he / Possesses such Knowledge or Experience ,
Or is Under Such Degree of Supervision as May be Appropriate having Regard to the Nature of the Work e.g.

Regulation 8 “ right one “
Earthing or Other Suitable Precautions
(i) Precautions Shall be Taken Either by Earthing or Some Other Means to Prevent Danger Arising e.g.
Do Not Carry Out Live Tests such as External Loop Impedance ( Ze ) or Final Circuit Loop Impedance ( Zs )
With Earth Conductors Disconnected , Guidance Note 8 , Earthing & Bonding ( Standards and Compliance )

State the Need for Instruments’ to be Regularly Checked and
The Need for Compliance with the Requirements of BS-7671:2008
HSE Guidance Note GS-38

All Instruments’ must be Regularly Checked to Ensure that they are ,
(1) Not Physically Damaged ,
(2) In Full Working Order ,
(3) Calibrated Correctly and to Date ,
(4) Compliant with GS-38 with Regards to Test Leads , the Main Requirements being ,

(i) Exposed Probe Ideally no more than 2mm / 4mm Maximum
(ii) Finger Guards to Stop Fingers Slipping onto Live Contact(s) ,
(iii) Test Leads or Test Probes include Current Limiting e.g. Fuse in Test Leads ,

(5) Safe to Use ,

Additional Protection RCD Test ↔ Instrument on mA Range 230v Supply ,
( Live Test , ½ No Trip ( x1 ( 300mS ) & x5 ( 40mS )

● Verification of Voltdrop ( Evaluate Using the Loop Impedance Value ) ↔ Note Normally Required on Initial Verification ,

● Electrical Separation ( Instrument on High Ohms ( MΩ ) Megohms Range ↔ Instrument Provides a Low Voltage ( 500v dc at 1mA )

● Insulation Résistance ( Instrument on High Ohms ( MΩ ) Megohms Range ↔ Instrument Provides a Low Voltage
( 250 / 500 / 1000 d.c ) at 1mA ( Regs table 61 )

● Insulation / Impedance of Floors & Walls ( Instrument on High Ohms ( MΩ ) Megohms Range ↔ Instrument Provides a Low Voltage
( 500v d.c. at 1mA to Read kΩ )

● Earth Fault Loop Impedance ↔ R1 + R2 ↔ ( Instrument on Low Ohms (Ω) Continuity Range ( Live Test ≈ ≈ ≈
( if New Installation Use OSG t-2D ↔ Cold Test at 80% , 1st ←←← ( 2392-10
( Regs Table 41.3 is Used for Warm Test 100%

● Prospective Fault Current ( Instrument on kA Range 230v Supply ( Live Test ≈ ≈ ≈ Dedicated Instrument ( or Settings )

● Check of Phase Sequence ( Instrument on Phase Sequence Setting 400v ( Live Test ≈ ≈ ≈ Dedicated Instrument ( or Settings )

● Functional Testing ( Check Test Button on RCD , Switches , Controls , Locks etc ,

● Electrical Test Equipment for Use by Electricians

Guidance Note GS-38
Circuits with Rated Voltages Not Exceeding 650v

LAW , ←←←

(2) The Electricity at Work Regulations 1989 Require those in Control of Part or all of an Electrical System to Ensure
That it is Safe to Use and that it is Maintained in a Safe Condition , This Section does not seek to give a Definitive Interpretation of the Law ,
It Summarises the Main issues to be borne in Mind when Carrying Out Electrical Testing ,
(3)
The Most Important Features that are Relevant for Electrical Test Equipment for Use by Electrically Competent People are as Follows ,

(a) Equipment should be , so far as Reasonably Practicable ,
(i) Constructed ,
(ii) Maintained , And
(iii) Used in a Way to Prevent Danger ,
(b) No Live Working Unless ,
(i) it is Unreasonable to Work Live , AND
(ii) it is Reasonable to Work Live , AND
(iii) Suitable Precautions are Taken to Prevent Injury ,

(c) Work must be Carried Out in a Safe Manner , Factors
To Consider when Developing Safe Working Practices
Include ,
(i) Control of Risk while Working ,
(ii) Control of Test Areas ,
(iii) Use of Suitable Tools & Clothing , Steel caps Boots ,
(iv) Use of Suitable Insulated Barriers ,
(v) Adequate Information ,
(vi) Adequate Accompaniment ,
(vii) Adequate Space , Access , Lighting ,

(d) People At Work Must ,
(i) Prevent Danger and Injury ,
(ii) Have Adequate Training , Skill & Experience ,
(iii) Have Adequate Supervision when Appropriate ,

 

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● Continuity of Protective Conductors’ ( Instrument on Low Ohms (Ω) Continuity Range , Instrument can read Values Less than , 1Ω
● Continuity of Protective Conductors’ ( R1+R2 Values , Metalwork & Effective ( IR ) Testing

● Continuity of Ring Final Circuit Conductors’ ( Instrument on Low Ohms (Ω) Continuity Range , Instrument can read Values Less than , 1Ω
● Continuity of Ring Final Circuit , ( R1+R2 Values , No Interconnected Ring )


● Insulation Résistance ( Instrument on High Ohms ( MΩ ) Megohms Range ↔ Instrument Provides a Low Voltage
( 250 / 500 / 1000 d.c ) at 1mA ( Regs table 61 )

● Insulation Résistance ( N0 Short between Line , Neutral & Earth


● SELV ( Instrument on High Ohms (MΩ) Megohms Range ↔ Instrument Provides a Low Voltage ( 250v dc at 1mA )

● SELV ( No Connection between Low & Extra Low Circuits )


● PELV ( Instrument on High Ohms (MΩ) Megohms Range ↔ Instrument Provides a Low Voltage ( 250v dc at 1mA )
● PELV ( No Connection between Low & Extra Low Circuits )


● Electrical Separation ( Instrument on High Ohms ( MΩ ) Megohms Range ↔ Instrument Provides a Low Voltage ( 500v dc at 1mA )

● Electrical Separation ( No Connection between Low & Extra Low Circuits )


● Insulation / Impedance of Floors & Walls ( Instrument on High Ohms ( MΩ ) Megohms Range ↔ Instrument Provides a Low Voltage
( 500v d.c. at 1mA to Read kΩ )

● Insulation / Impedance of Floors & Walls ( Effectiveness of High Résistance / Impedance Location )


● Polarity ( Instrument on Low Ohms (Ω) Continuity Range , Instrument can read Values Less than , 1Ω

● Polarity ( Switches , Fuses , Breakers etc in Side of Circuit )


● Earth Electrode Résistance ( Instrument on Low Ohms (Ω)Continuity Range , Dedicated Instrument ( or Setting ) read Less than , 1Ω
Earth Rods , / Battery only ,

● Earth Electrode Résistance ( Resistive Contact of Electrode to Ground )


● Earth Fault Loop Impedance ↔ R1 + R2 ↔ ( Instrument on Low Ohms (Ω) Continuity Range ( Live Test ≈ ≈ ≈ ≈
( if New Installation Use OSG t-2D ↔ Cold Test at 80% , 1st ←←← ( 2392-10
( Regs Table 41.3 is Used for Warm Test 100%

● Earth Fault Loop Impedance ( To Meet Final Circuit Disconnection time in Event of Fault )


● Prospective Fault Current ( Instrument on kA Range 230v Supply ( Live Test ≈ ≈ ≈ ≈ Dedicated Instrument ( or Setting )

● Prospective Fault Current ( To Ensure Protective Devices can Disconnect Fault Effectively ) ↔ ( PFC )


● Check of Phase Sequence ( Instrument on Phase Sequence Setting 400v ( Live Test ≈ ≈ ≈ ≈ Dedicated Instrument ( or Settings )

● Check of Phase Sequence ( To Ensure 3 Phase Motors etc Rotate Incorrect Direction )


● Functional Testing ( Check Test Button on RCD , Switches , Controls , Locks etc ,

● Functional Testing ( To Test RCD Test Button , Switches’ , Breakers , Locks etc Operate )


● Verification of Voltdrop ( Evaluate Using the Loop Impedance Value ) ↔ Note Normally Required on Initial Verification ,

● Verification of Voltdrop ( To Ensure Voltage at Load End is within Required Limits )

Domestic Electrician 2392-10

Insulation Résistance , 2392-10

Cables Connected in Parallel ,

The Formula for Calculating Overall Insulation Résistance of Circuits in Parallel ,

1 = 1 + 1 + 1 + MΩ
----- ----- ----- -----
RT R1 R2 R3

Where RT is the Overall Insulation Résistance ,
Three Circuits’ of Résistance 1MΩ 2MΩ 4MΩ Connected in Parallel ,
R1 ,R2 , R3

1 = 1 + 1 + 1
---- ---- ---- ----
RT R1 R2 R3

1 = 1 + 1 + 1
---- ---- ---- ---- ( 1 ÷ 1 + 1 ÷ 2 + 1 ÷ 4 = 1.75
RT 1 2 4

1 = 1 + 0.5 + 0.25 = 1.75
---- ---- ---- ----
RT

1 = 1.75
----
RT

RT = 1
----- ( 1 ÷ 1.75 = 0.57 MΩ
1.75

RT = 0.57 MΩ

Insulation Résistance
Precautions to be Taken before Testing Insulation Résistance ,

(a) Isolation of Circuits and Equipment , ♫
(b) Voltage Sensitive Equipment , ♫
(c) Electronic Components , ♫

(a) Isolation of Circuits and Equipment ,
The Following Procedure for Safe Isolation should be Taken , ♫
1 , Select a GS-38 Approved Test Lamp or Voltage Indicator , ♫
2 , Check Test Lamp / Voltage Indicator is Functioning Correctly by Testing on a Known Supply or Proving Unit ♫
3 , Determine whether Isolation is for Whole Installation or Specific Circuit(s)
4 , Locate Means of Isolation Ensuring there is No Standby Supply Arrangement ,
5 , Switch Off and Lock Off Isolator , Circuit(s) e.g. Fuse , Switches’ , Isolator , MCB etc ♫
6 ,Verify , Using Test Lamp / Voltage Indicator , Circuit(s) are Dead between Line(s) Neutral & Earth , ♫
7 , Erect Warning Notice(s) in Appropriate Position(s) e.g. at the Consumer Unit , ♫
8 , Re-Check Test Lamps / Voltage Indicator is Still Functioning Correctly , ♫
9 , Retain Key(s) for Locking Off Devices , ♫

(b) Before Carrying Out Insulation Résistance Testing it Must be Established that there is No Voltage
Sensitive Equipment Connected that may be Damaged or Malfunction because of Test Voltage Applied ,
May be Computers , Programmable Logic Controllers (PLCs) Programmers etc.
The Equipment would Either have to be Disconnected During Test ,
Or Insulation Test with Line(s) and Neutral Connected Together and Test between these and the Protective Conductor ,

(c) Before Carrying Out Insulation Résistance Testing it Must also be Established that there is No Electronic Components
That May be Damaged or Malfunction because of the Test Voltage Applied , Lamp Dimmer , this would have to be Removed
During Test and the Switch Wires Connected Together ,

Methods of Testing Insulation Résistance

Before Carrying Out Insulation Résistance Testing Ensure that ,

1 , All Lamps , Capacitors and Loads are Disconnected ,
2 , Voltage Sensitive Electronic Equipments such as Dimmer Switches , Touch Switches ,
Delay Timers , Power Controllers , Fluorescent Lamps Starters , Emergency Lighting ,
RCDs etc are Disconnected ,
3 , There is No Electrical Connections between Line(s) Neutral & Earth ,

● Verification of Voltdrop ( Evaluate Using the Loop Impedance Value ) ↔ NOT Normally Required on Initial Verification , ( Sorry this is the right one ) ←←←←←←

● As a Cable Increases in Length , Unlike the Conductor Résistance which Increases with Length ,
Insulation Résistance Decreases with Length ,

Formula for Calculating New Value of Insulation Résistance ,
( Insulation Résistance = Original Length x Initial Insulation Résistance )
“ New Length “

A Cable of Length 50 metres has an Insulation Résistance Value of 200MΩ if its Length
Is Increased to 100 metres , Calculate its Insulation Résistance ,

= 50 x 200
-------------- ( 50 x 200 = 10000.
100

= 10,000
-----------
100

= 100MΩ

● Earth Electrode Résistance ( Ze )

● Earth Fault Lop Impedance ( Ze ) ( Zs )

● Prospective Fault Current ( PFC )

 

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“ Cables “ & Stuff (1) this will make it easy for you all in one ?

● A Reference Method Indicates , ( The Instillation Method )

● A Final Circuit is Wired between the , ( Distribution Board and Current Using Equipment )

● The Reading Provided when Cross Connecting the Incoming Phase and the Outgoing CPC and Vice versa on a Final Ring Circuit Test would be
( R1 + R2 )

● What’s the Function of a “ Shorting Lead “ when Conducting Continuity , ( R1 + R2 ) Tests ( “ It Completes the Live to CPC Test Loop ” )

● An Initial Check at the End of a Ring Final Circuit would Not Indicate ( Interconnections )

● The Earth Fault Loop Impedance Reading on a Ring Final Circuit is best Achieved Using an Earth Fault Loop Impedance
Tester and , ( BS -1363 Fly Lead )

● When Applying the Rule of Thumb Method , the Value of Prospective Short-Circuit Current for a 3 Phase Supply should be ,
( Twice the Single Phase Value )

● When Carrying Out a Prospective Short Circuit Fault Current Test on 3 Phase Systems the Approximate Fault Current between Phases should be
( Double the Fault Current between One Phase & Neutral )

● the Most Convenient Method of Determining the Value of the Prospective Short Circuit Current at the Origin of an Existing Installation would be ,
( Measurement )

● Method of Determining the External Loop Impedance ( Taking Reading at the Origin of the Supply )

● Earth Fault Loop Impedance Test Performed on a Ring Circuit will Record
( Resistance of Line and Protective Conductors and External Loop Impedance

● Electrical Installations Shall be Divided into Circuits to ( Reduce Unwanted Tripping of RCD )

● To Ensure the Protective Device Operates Requires a ( Low Fault Loop Impedance Path with a Resultant High Earth Fault Current Flow )

● The Effects of Creating a Ring Final Circuit would be that the Overall Resistance of the Conductors would ( Decrease )

● The Resistance in Ohms , of a Conductor ( Increases with Increase of Cable Length )

● if you Double the Length of Wire ( you will Double the Resistance of the Wire )

● if you Double the Cross-Sectional Area of a Wire you will Cut its Resistance in ( Half )

● What is the Preferred Way of Reducing Excessive Voltage Drop in a Circuit , ( Increased Cable CSA )

● the Value will Decrease as we Move Farther away from the Intake Position ( Resistance Increases with Length )

● End to End Resistance Checks would be Carried out on a ! ( Ring Final Circuit )

● To Ensure the Protective Device Operates Requires A ( Low Fault Loop Impedance Path With a Resultant High Earth Fault Current Flow )

● As a Cable Increases in Length , Unlike the Conductor Résistance which Increases with Length ,
( Insulation Résistance Decreases with Length )

Residual Current Operated Circuit Breaker ( BS-EN 61008-1
BS-EN 61008-1 : 2004 Residual Current Operated Circuit –Breaker without Integral Overcurrent Protection for Household
And Similar Use ( RCCBs )
Replaces ( BS-EN 61008-1 - 1995 )
International Relationships ( EN-61008-1: 2004 Identical , IEC-61008-1: 1996
Amended by / AMD 17447 November 2007

BS-EN 61009-1 / 1995
Electrical Accessories , Residual Current Operated Circuit Breaker with Integral Overcurent Protection for Household and
Similar Uses ( RCBOs ) General Rule CU , Regs 41.3
International Equivalent EN-61009-1 / IEC 61009-1: 1991
Replaces by BS-EN 6009-1 : 2004 ( Remains Current ) Appendix 1 p-236

2.1 (a) BS-7671 IEE Regulations Define Extra-Low-Voltage a.c ( Not Exceeding 50V , ps this one is still ongoing

531.2.9 Where , for Compliance with the Requirements of the Regulations for Fault Protection or Otherwise to Prevent Danger , Two or More RCDs are in Series , and where Discrimination in their Operation is Necessary to prevent Danger , The Characteristics of the Devices shall be such that the Intended Discrimination is Achieved ,

411.8.3 Requirements for Fault Protection where a Circuit-Breaker is Used , the Maximum Value of Earth Fault Loop Impedance (Zs) shall be Determined by the Formula in Regulation 411.4.5 , Alternatively , the Values Specified in Table 41.6 may be Used Instead of Calculation for the Nominal Voltages (Uo) and the Type and Ratings of Overcurrent Device Listed therein ,

Operation of the Overcurrent Device in Tables of , 41.3 / 41.4 ( where Circuit Lengths’ need to be Limited )

132.11 Prevention of Electrical Equipment , the Electrical Installation shall be Arranged in such a way that No Mutual Detrimental Influence will Occur between Electrical Installation and Non- Electrical Installation Electrical Installation ( Condensation , Smoke , Heat , Thermal Installation , Electromagnetic Interference , / sec , 515 – 528 ,

Telecommunications Systems-BS 6701 ( Operates 50v d.c / Ringing Voltage in Excess off 80v a.c )

Mac I’ve got Problems with down Loading onto the Forum
My Sizing going to pot
An having to down load one at a time , and dropping it to size 8
PS can you see Dan ,

Sorry Caps I have to stop Down Loading stuff , Amberleaf

 

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Outgoing Circuits

An Rcd with a Residual Operating Current Not Exceeding 30mA is Recognised Device for Providing Additional
Protection in the Event of ,
1 , Electrical Fault ,
2 , Failure of Basic Protection ,
3 , Carelessness by the User or Operator ,
Such RCDs should Not be Used as Sole Means of Protection and do Not avoid the need to Apply one or more of the Protective Measures ,
Detail in the Regulations ,
Under the New Regulations , an Installation is Required to Incorporate One or More RCDs Depending on the Circumstances ,

The Regulations Affecting RCD Protection

411.3.3
Additional Protection by Means of a 30mA RCD is to be Provided for all Socket-Outlets with a Rated Current Not
Exceeding 20A for Use by Ordinary Persons ,
The Only Exceptions Allowed are for Socket-Outlets for Use Under the Supervision of “ Skilled “ or Instructed Persons e.g.
Some Commercial / Industrial , Locations or a Specifically Labelled Socket Provided for Connection of a Particular
Item of Equipment , Such as Freezer ,

701.411.3.3
In Specific Locations such as those Containing a Bath or Shower there is Now a Requirement to Provide RCD Protection
On all Circuits , Including Lighting and Shower Circuits ,

314.1 & 2 / 531.2.4
Every Installation should be Provided into Circuits as Necessary to Avoid and Minimise Inconvenience in the Event of a Fault ,
Designers are Required to Reduce the Possibility of Unwanted RCD Tripping due to Excessive Protective Conductor Currents
But Not due to an Earth Fault ,
Separate Circuits’ may be Required for parts of the Installation which need to be Separately Controlled in such a way
That they are Not Affected by the Failure of other Circuits ,
The Appropriate Subdivision should take Account of any Danger arising from the Failure of a Single Circuit ,
RCD Trip Causing the Disconnection of an Important Lighting Circuit ,

522.6.7
Much Greater Use of RCD is Required to Protect Wiring Concealed in Walls or Partitions , even where this is Installed
In Previously Defined Safe Zones ,
This Effectively means that all Concealed Wiring at a Depth of Less than 50mm from the Surface now Requires
Protection by 30mA RCD Unless Provided with Earthed Mechanical Protection ,

RCBO BS-EN 61009-1 is a Combination of an MCB & RCD This Enables Both Overcurrent Protection & Earth Fault Current protection and detection
Protection by a Single Unit

IP Rating , RCBO Front Plate IPX4 / Screw IPX2 ←

These may be Operated with our without Overcurrent Protection ( RCBOs )
With Single Pole RCBOs , even when they have Tripped , the Neural Wire is still Not Interrupted ←←
The RCBO will Trip and Cut off Power ,

RCCBs BS-EN 61008-1
Voltage Dependent RCCBs are Reliant on the Line Voltage to Trip the Switch through an Electronic Control Device ,
RCCBs
Provides Protection Against Earth Faults Occurring in Equipment and Reduces the Effects of Electrical Shock ,
RCCBs Measures the Current Flowing in the Line & Neutral Cables
And if there is an Imbalance , that is Current Flowing to Earth above the RCCB will Trip and cut off the Supply

Selection of conductors’ for Current Carrying Capacity & Voltage Drop
Are the Cables the Correct size for the Current which they have to Carry and is the Voltage Drop
In the Circuit below the Permitted Value ,
Regulations 523 / 524 / & 525 – part 4 ,

Erection Methods
Has the Installation been Erected to Comply with BS07671 Part 5

Regulations table 4A1 , appendix 4 & 522 ,
Correct Type of Installation to Suit Environment , Standard of Workmanship and Suitability of Fixings ,

Routing of Cables and in Prescribed Zones or within Mechanical Protection
Regulations 522.6 BS7671 & 7.3 OSG , Intended for use when Completing an Electrical Installation Certificate ,
Only Limited Inspection would be Possible during a Periodic Inspection Report ,

Connection of Conductors
Regulations 526 . Check for Tightness & Correct use of Terminations at a Random Selection of Accessories and all Distribution Boards ,

Presence of Fire Barriers , Suitable Seals & Protection against Thermal Effects
Reg , chapter 42 & section 527 ,
This is to Ensure that Structural Fire Barriers are not broken During Installation ,
Fire Barriers are Present in Trunking & Ducting where Required , and Intumescent hoods on Lighting where
Installed in Fire Rated Ceilings , Heat from Installed Equipment must Not be Likely to Cause a Fire ,
Particularly , Check that backless Accessories such as wall Lights and Electrical Enclosures are Installed
On Surfaces Suitable for Surface Temperatures & Radiated heat of Equipment

General ,
Presence and Correct Location of Appropriate Devices for Isolation and Switching ,
Reg , chapter 53 sec 7 Isolators Identified where not Obvious ,
Local and Under the Control of user or , if Remote , they must be Lockable and Identified Isolation of Fans with Timers Controls
In Bathrooms ( table 53.2 p-117
For Correct Selection of Devices ,

“ Periodic Inspection Report “

This Document is Used to Record the Condition of the Installation In Particular , is it Safe to Use ,
It is , however , Important that the Person Carrying Out the Inspection and Test is Competent ,

This Report must Also include a Schedule of Test Results and a Schedule of Inspection ,

A Periodic Inspection Report is Carried Out for Many Reasons ,
(i) The Due Date ,
(ii) Clients / Customers Request ,
(iii) Change of Ownership ,
(iiii) Change of use , Insurance Purposes
To Inspect the Condition of the Existing Installation , Prior to Carrying out any Alterations or Additions ,

The Frequency of the Periodic Inspection and Test is Dependent on the Type of Installation ,
The Environment and the Type of Use , BS 7671 Wiring Regulations refer to this as the ,
( Construction , Utilization and Environment )
Appendix 5 BS 7671 ,

Guidance Note 3
For the Inspecting & Testing of Electrical Installations has a Table of Recommended Frequencies for Carrying Out
Periodic Inspection & Tests / The Period Depends on the Type of Installation ,
The Recommended Frequencies , it is the Responsibility of the Person Carrying Out the Periodic Inspection & Tests
To Decide on the Period between Tests ,
This Decision should be Based on the Inspectors Experience ,
What the Installation is Used for ,
How Often it is Used , The Type of Environment that Surrounds the Installation ,
Many Others should be Taken into Account when Setting the Next Test Date ,

It is Important to Remember that the Date of the First Inspection & Test is set by the Person Responsible for the Installation Design , ( Change of Use or Ownership )

Careful Consideration must be Given to the Installation before the Date of the Next Periodic Inspection & Test is Set , ←←←←
It is Very Important that the Extent and Limitations of the Inspection and Test is Agreed with the Person Ordering the Work
Before Commencing Work ,

Before the Extent and Limitations can be Agreed , Discussion between all Parties involved must take Place , ←←←←
The Client will know why they want the Inspection Carried Out and the Person who is Carrying Out the Inspection and Test should have the Technical Knowledge and Experience to give the Correct Guidance ,

Test Results , Electrical Installation , / Periodic Inspection Reports
Fuse , Charts etc must be Made Available to the Person Carrying out the Inspection & Test , ←←←

If these are Not Available , then a Survey of the Installation must be Carried Out to Ensure that the Installation is Safe
To Test and to Prepare the Required Paperwork , such as Fuse Charts ,

Whist Carrying Out a Periodic Inspection & Test it is Not a Requirement to take the Installation Apart ,
This Should be Carried Out with the Minimum of Intrusion ,
Disconnection should Only be Carried Out when it is Impossible to Carry Out the Required Test
In any Other way , if an Insulation Résistance Test is Required on a Lighting Circuit with Fluorescent Lighting Connected to it ,

Would be to Open the Switch Supplying the Fluorescent Fitting before Testing between the Live Conductors ,
And Close the Switch when Conducting the Test between Live Conductors and Earth ,
It is Not a Requirement to Disconnect the Fitting
( Insulation Résistance Testing , Chapter 4 )

 

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Supply , Characteristics , Earthing & Bonding Arrangement
Supply , Characteristics , Nominal Voltage of the Supply
System Type TT . TN-S or TN-C-S ,

Nominal Frequency , Normally 50Hz , 110.1 ( xv )

● Prospective Fault Current ,
The Highest Current that could Flow within the Installation between Live Conductors , or Live Conductors & Earth ,
This should be Measured or Obtained by Enquiry , if Measured , Remember that on a ( 3 ) Phase System
The Value between Phase & Neutral must be Doubled ←←←

● External Earth Loop Impedance , ( Ze ) this is the External Earth Fault Loop Impedance Measured between the
Phase & Earthing Conductor for the Installation ,

Characteristics of the Supply Protective Device ,
● BS- Type , can Normally be Found Printed on the Service Head ,
● Nominal Current Rating , can Normally be found Printed on the Service Head ,
● Short-Circuit-Capacity , this will Depend on the Type , If in Doubt Reference / T- 7.4 OSG ,
● Main Switch or Circuit-Breaker , Type is Normally printed on it , ( Appendix 2 – BS-7671 if Required )
● Number of Poles , Does the Switch Break all Live Conductors when Opened ( or is it Single-Pole Only )
● Supply Conductor Material & Size , ( Refers to Meter Tails )
● Voltage Rating , ( this will Usually be Printed on Device )
● Current Rating , ( this will Usually be Printed on Device )
● RCD Operating Current , ( I∆n ) this is the Trip Rating of the RCD & should Only be Recorded if
The RCD is Used as a Main Switch )
● RCD Operating Time at ( I∆n ) Only to be Recorded if the RCD is Used as Main Switch ,
Means of Earthing ,
Distributors , Facility or Earth / Electrode ,
Type , if Earth / Electrode ,
Electrode Résistance , Usually Measured as ( Ze )
Location , where is the Earth / Electrode ,

Method of Measured ,
Has an Earth Fault Loop Tester or an Earth / Electrode Tester been Used to Carry Out the Test ,
To do this Test Correctly , the Earthing Conductor shall be Disconnected to Avoid the Introduction of Parallel Paths ,
This will of Course Require Isolation of the Installation ,
In some Instance this May Not be Practical or Possible , ( for Reasons )

If Isolation is Not Possible , the Measurement should still be Carried Out to Prove that the Installation has an Earth ,
The Measurement Value of ( Ze ) should be Equal to or Less than any Value for ( Ze ) Documented on Previous
Test Certificates ,
If the Measurement is Higher than those Recorded before , then Further Investigation will be Recorded ,

The Higher Measurement could be Caused by Corrosion ,
Loose Connection / or Damage ,

If the Means of Earthing is by an Earth Electrode ,
The Soil Conditions may have Changed , this would be Considered Normal Providing that the Measured Value
Is Less than ( 200Ω ) 411.5.3 Note 2 ,
And the systems is Protected by a Residual Current Device ,

Main Protective Conductors

Earthing Conductor
Conductor Material , What is it Made of ,
Unless Special Precautions are Taken in Accordance / BS-7671 ( this should be Cooper )

Conductor Cross-Sectional Area
This must Comply with Regulation Sec / 543 ,
If the System is PEM then Regulations 544.1
In most Domestic Installation’s this will Require ( 16mm2 ) further Information / 4.1 OSG ,

Continuity Check
This Requires a tick Only and is Usually a Visual Check ( Provided that the Conductor is Sound )

Main Equipotential Bonding Conductors ↔ ( Main Protective Bonding Conductor ) Regs p-32
Conductor Material
What is made of ,
Unless Special Precautions are Taken in Accordance / BS-7671 ( this should be Cooper )

Conductor Cross-Sectional Area
Must Comply with Regulations 544.
In Most Domestic Installations the Required Size is ( 10mm2 )
Information Available ( T – 10A / OSG )

Bonding of Extraneous Conductive Parts ,
All Services , Structural Steel , Lighting Conductors’ & Central Heating Systems should be Equipotential Bonded ↔ ( Main Protective Bonding Conductor ) Regs p-32
Regulations 411.3.1.2 ( Chap 4 - OSG
Normally a Tick Required ,

Sorry Chaps am going to Spec Savers ( PME , Protective Multiple Earthing

Correct Selection of Protective Devices

When Carrying Out an Inspection & Test on any Electrical Installation it is Important to Ensure that the Correct Size
And Type of Device has be Selective and Installed
Selection of Protective Devices and the Type of Circuits that they are Protecting ,

Protective Devices are Installed to Protect the Cable of the Circuit from Damage
This could be Caused by Overload / Overcurrent & Fault Current ,
( Overcurrent Occurring in a Circuit which is Electrically Sound ,
( Overcurrent is a Current Flow in a Cable which is Greater than the Rated Current-Carrying-Capacity of the Cables )
( Fault Current is a Current which is Flowing in a Circuit due to a Fault )

Will the Device be able to Safely Interrupt the Prospective Fault Current which could flow in the Event of a Fault
OSG. 7.4 or the Manufacturers Literature will Provide Information on the Rated Short-Circuit-Capacity of Protective Devices ,

Selection of Electrical Equipment ( Domestic Electricians 2392-10 )
133.1.1
Every item of Equipment shall Comply with the Appropriate British Standard ,
In its Absence of an Appropriate British Standard , Reference shall be Made to the Appropriate IEC Standard
Or the Appropriate National Standard of Another Country ,
133.1.2
Where there are No Applicable Standards , the Item of Equipment Concerned shall be Selected by Special Agreement between the Person Specifying the Installation and the Installer ,
133.1.3
Where Equipment to be Used is Not in Accordance with Regulation 133.1.1 or is Used Outside the Scope of its Standard ,
The Designer or Other Person Responsible for Specifying the Installation shall Confirm that the
Equipment Provides at Least the Same Degree of Safety as that Afforded by Compliance with the Regulations ,

Appendix 2 of BS-7671 Covers Statutory Regulations

Testing

To Ensure No Danger to Persons & Livestock and that No Danger Occurs to Property ,
To Compare the Results with the Design Criteria
Take a View on the Condition of the Installation and Advise on Any Remedial Works Required ,
In the Event of a Dangerous Situation ,
To Make an Immediate Recommendation to the Client to Isolate the Defective Parts ,

To Ensure the Fault is Repaired and Retest Any Parts of The Installation which Test Results May have been Affected by the Fault ,

A Circuit Breaker is Really two Devices in One Unit ,
The Overload part of the Device is a Thermal Bi-Metal Strip ,
Which heats up when a Current of a Higher Value than the Nominal Current Rating ( In ) of the Device Passes through it ,

Also Incorporated within the Device is a Magnetic Trip ,
Which Operates and Causes the Device to Trip when a Fault Current Flows through it
For the Device to Operate Correctly it must Operate within 0.1 seconds
The Current which has to flow to Operate the Device in the Required time has the Symbol ( Ia )

B Type MCBs
Should be Used on Circuits having Only Resistive Loads ,
C Type MCBs
Used for Inductive Loads such as Fluorescent Lighting , Small Electric Motors & other Circuits Where Surges could Occur ,
D Type MCBs
Used on Circuits Supplying Large Transformers or any Circuits where High Inrush Currents could Occur

Adequacy of Access to Switchgear and Other Equipment
Regulations 412.2.2.3 / 513.1 / 526. 3 / 537 / 543 / 559.10.3.1 (iii) OSG, 8.4
Doors of Enclosures must be Removable or able to be fully Opened ,
Access to Equipment should not be Obstructed ,
Cooker control switches within 2 meters of cooker & hob , app 8 , 8.4 OSG

Connection of Single Pole Devices for Protection and Switching in Line Only ,
Regulations 530.3.3 / 612.6
Switches in Phase and not Neutral Conductors, Generally Carried out when Continuity of CPC Tested along with a Visual Check ,

Correct Connection of Accessories & Equipment
Regulations 52 , section 6 Correct and Neat Connection ,
Look for Excessive Exposed Conductors , Cores of Cables not cut out where Terminal full ,
For Connection of fine wire Cables 526.8

Selection of Equipment & Protective Measures Appropriate to External Influences
Appendix 5 Regulations 512.2 chapter 52 sec 2
Check for the Suitability of a Wiring Systems for the Environment and Type of use to which it is being put
For Outdoor Lighting Regulations 559.10.4. / 559.10.5.1

Selection of Appropriate Functional Switching Devices
Regulations 537.5.2 table 53.2 Correct Operation of Switches / Isolators , throughout Installation

4 Earths / in Domestic’s , 16mm2 , 10mm2 , Presence of Supplementary bonding , CPC in Cables ,

“ At the Consumer Unit “
Before you Start this must be Isolated ,
The Electricity at Work Regulations 1989 States that it is an Offence to Work Live
Once you Remove a Cover you will be Working Live if you do Not Isolate it First ,
Having Carried Out Safe Isolation Procedure , Remove the Cover of the Consumer Unit

Part P Domestic Electrical Installation Certificate
An Electrical Installation Certificate is Required for ,
● A New Installation ,
● When New Circuits are Installed ,
● When a Single Circuit is Installed ,
● The Changing of a Consumers’ Unit ,
● When a Circuit is Altered and the Alteration Requires the Changing of the Protective Device ,

 

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Domestic Electricians’
510.2 Every Item of Equipment shall be Selected and Erected so as to Allow Compliance with the Regulations Stated
In this Chapter and Relevant Regulations in Other Parts of BS-7671 and shall take Account of Manufacturers Instructions ,
511 Compliance with Standards
511.1 Every Item of Equipment Shall Comply with the Relevant Requirements of the Applicable British Standard
Or Harmonized Standard , Appropriate to the Intended Use of the Equipment ,
The Edition of the Standard shall be the Current Edition , with those Amendments Pertaining at a Date to be Agreed by
The Parties to the Contract Concerned ( App 1 )

511.1 Alternatively , if Equipment Complying with a Foreign National Standard based on an IEC Standard is to be Used
The Designer or Other Person Responsible for Specifying the Installation shall Verify that any Differences between that
Standard and the Corresponding British Standard or Harmonized Standard , will Not Result in a Lesser Degree of Safety than that Afforded by Compliance with the British Standard

511.2 Where Equipment to be Used is Not Covered by a British Standard Or Harmonized Standard , or is Used Outside the Scope
Of its Standard , the Designer or Other Person Responsible for Specifying the Installation shall Confirm that the Equipment
Provide the Same Degree of Safety as that Afforded by Compliance with the Regulations ( British Standard )
( Selection of Electrical Equipment ( 133.1.1 / 133.1.2 / 133.1.3 )

133.2 Characteristics ,
Every Item Electrical Equipment Selected shall have Suitable Characteristics Appreciate to Values and Conditions on
Which the Design of the Electrical Installation , @

Domestic Electrical
( Zs ) is the Earth Fault Loop Impedance ( Zs = Ze + R1 + R2 ) ( Zs ) is the Measurement of the Whole Fault Path R1 + R2 ) Measurement of the Circuit of Installation then ( Zs ) then has to be Low Enough to Allow Current to Flow in Order for the Protective Device to Operate New Installation , ( Values off 80% OSG T-2D ( Electrical Installation Certificate Regs – p-334 ) 1st ← ← Maximum ( Zs ) ( Values off 100% Regs – p-41.3 ( Ze ) PFC ↔ Test ( 230 ÷ 0.04 = 5750Ω , Calculation ( 6kA ) PSCC Test Across Live / Neutral , 434.5.1 PFC is Between Live / Earth ( you have Measured PFC ) PFC is the Highest of the Two Readings ( Noted on Test Cert , PSCC Prospective Short-Circuit Current ( L / N PFC Prospective Fault Current ( L / E ( Zs )

 

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Sorry Chaps Jason going to have My Cuts for Carters , ( Jason will be on Prozac )
“ Documents “ ● Electricity at Work Regulations 1989 - Statutory ● IEE Guidance Note 3 – Inspection & Testing – Non- Statutory ● BS-7671 Requirements for Electrical Installations – Non- Statutory ● IEE Onsite Guide - Non-Statutory ● HSE Guidance Note GS38 - Statutory
● Next Inspection on Domestic Premises = Maximum - Ten Years , ● The age of the Installation , Change of use, Request of Insurers, Change of Ownership, Following Damage, etc,
“ New Cooker Circuit “ ● Certification / Documentation , ● Electrical Installation Certificate ● Schedule of Inspections ● Schedule of Test Results A New Circuit has been Installed back to the Origin ( Cooker ). This Requires an Electrical Installation Certificate. On replacing the Consumer Unit, you are changing the Protective devices and need to Confirm that Existing Circuits are Adequately Protected and Conform to BS-7671 ,
“ Test schedule “ ● Schedule of Inspections , ● Test Instrument Details ● Make and Model ● Serial Number ● Type of Supply / Earthing Arrangements , Regs , p-32 ● External Earth Loop Impedance – ( Zs ) ● Prospective Fault Current ( PFC ) 612.11
● Routing of cables in prescribed zones ● Selection of conductors for current carrying capacity ● Erection methods ● Presence and Correct Location of Appropriate Device for Isolation and Switching… Etc , ● Practical problems , ( Circuit Tails not Long Enough )
“ Test sequence “ Cooker Circuit “ Tests “ GN-3 ● (1) Continuity of Protective Conductors 612.2.1 (1) Full sequence is given in Regulation 612.2.1.
● Insulation Resistance ● Polarity (usually in conjunction with (1) 612.6 ( Dead Test )
GN-3 ● Earth Fault Loop Impedance , ( Live Test ) 612.9 ● Operation of Switch / Isolator , ( Functional Testing ) 612.13.2
“ Instruments “ ● Low-reading ohmmeter – Ohms , ● Insulation Resistance Tester – M W , ● Loop Impedance Tester – Ohms ,
“ Inspection & Test of Industrial Unit “ ● Periodic Inspection Report ● ( Referring to question ) Extent and Limitations of the Inspection ● The ‘Person Ordering the Work’ ( the Client ) ↔ Originals Retained by Client (‘Person Ordering the Work’ )
“ Minor Works Cert “ ● System Earthing Arrangements ●Type and Rating of Protective Device for Modified Circuit
“ Units “ ● mA (and ms) milli-A mps ( and milli-seconds ) “ Sequence of tests “ GN-3 ● Continuity of protective conductors ● Continuity of ring final circuit conductors ● Insulation Resistance ● Polarity

 

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“ Earthing / Bonding Terminology “ Regs , p-32 ● Main Earthing Conductor ● Circuit Protective Conductor ● Supplementary Protective Bonding Conductors ( where required )

“ IP Codes “ ● IP4X top Distribution Board , 416.2.2 ● IP2X or IPXXB side Distribution Board ● Domestic-Switchgear , by use of tool or key , ( 416.2.4 )

“ CPC Continuity Test “ ● Low Reading Ohmmeter / W - Ohms , ● Either Zero the meter with leads connected to each other, or record the resistance of the leads and deduct it from measurements. ● Last point (or highest reading) is the value of (R1 + R2) for the circuit

“ Ring Circuit Continuity “ ● Verify continuity of CPC. Confirm a Ring exists without ↔ Interconnections ↔ obtain values of R1 and R2 with which to compare Directly measure ( R1 + R2 )

“ Insulation Resistance “ MW - Mega-Ohms , “ Isolate Installation from Supply “ ≈ ● Remove all lamps ←← ● Disconnect all Sensitive Equipment – Dimmers , Neon’s , Fluorescents etc , ( a must ) ● Close all Switches ↔ ● Check test leads ↔ ● Set Meter tester to 500V d.c. ● Test between Live / Neutral - Live / CPC and Neutral / CPC , ≈ ● Lowest Reading Must be Greater than 2 MW. If a Lower Reading is Obtained then Circuits must be Tested Individually ,
“ Insulation Resistance of SELV and PELV Circuit “ 612.3.2 ● 250V d.c. ● ≥ 0.5 MW ● 500V d.c. ● ≥ 0.1 MW “ Insulation Resistance Values “ ● 0.00 MW = Dead Short , ● 0.08 MW = Low Insulation Resistance Fault , ● ≥ 200 MW = Healthy Circuit ,
“ Loop Impedance “
● To Determine that an Earth Fault path Exists and is low enough to allow Sufficient Current to Flow in the Event of a Fault to Operate the Protective Device within the Prescribed Times , ● Increase the size of CPC to bring it up to 17th Edition if needed ( The method is to use an RCD 30mA ) ● The Highest Zs Value is Recorded. ● The Earth Fault Loop Impedance must be low enough to comply with the Requirements of the Protective Devices in the New CCU. Also it is essential to Verify that an Earth Fault Path Exists before a Circuit is Connected to the New CCU ,

“ 30mA RCD “ mA (and ms) milli-A mps ( and milli-seconds ) ● For Operation of Portable Equipment Outside the Main Protective Bonding Conductor Zone , ● To meet Disconnection Times if Zs is too high , ● For fixed Equipment in Bathrooms , ● For all Sockets on a TT system ,

“ 500mA RCD Tests “ ● Apply 50% current (250mA) – RCD should not trip on either half-cycle , ● Apply 500mA (rated current) – RCD should operate within 300ms , ● Test ‘T’ button to verify Electro-Mechanical Operation. ( Functional Test ) 612.13

↔↔ Insulation Resistance Tester – M/Ohms ↔↔ the Ω Sign didn’t get through Sorry ( M W ) should be Ohms ←

“ Prospective Fault Current at origin “ ● Maximum Zs values given in Schedule of Test Results , ● In this case the Zs values must Be Calculated and this fact Noted on the Test Schedule ● The Type and Rating of the Distributors’ fusible cut-out or protective device , ● Basic Information Required , Nature of Supplies 313.1 / O.S.G p-13 , ● You’ll Need to Write this in your Schedule of Test Results , when your Finished the Testing on the Board(s)

 

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Electrical Installation Certificate

The Electrical Installation Certificate is to be Used Only for the Initial Certificate of a New Installation or for Alteration or Addition
To an Existing Installation where New Circuits have be Introduced ,

It is Not to be Used for Periodic Inspection for Which a Periodic Inspection Report Form should be Used ,
For Alteration or Addition which Does Not Extend to the Introduction of New Circuits ,
( a Minor Electrical Installation Works Certificate may be Used )

The Original Certificate is to be Given to the Person Ordering the Work ( 632.3 ) p-163
A Duplicate should be Retained by the Contractor ,

Electrical Installation Certificate
(i) the Electrical Installation Certificate Required by Part 7 shall be Made Out and Signed or Otherwise Authenticated by a
Competent Person or Persons in Respect of the Design ,

(ii) the Minor Works Certificate Required by Part 7 shall be Made Out and Signed or Otherwise Authenticated by a
Competent Person or Person in Respect of the Inspection & Testing of an Installation

(iii) the Periodic Inspection Report Required by Part 7 Out and Signed or Otherwise Authenticated by a Competent Person
In Respect of the Inspection & Testing of an Installation ,

(iv) Competent Persons will , as Appropriate to their Function Under (i) – (ii) – (iii) Above ,
Have Sound Knowledge and Experience Relevant to the Nature of the Work Undertaken and to the Technical Standards
Set Down in this British Standards ,
Be Fully Versed in the Inspection and Testing Procedures Contained in this Standard and Employ Adequate Equipment ,

(v) Electrical Installation Certificate will Indicate the Responsibility for Design ,
Construction , Inspection & Testing , whether in Relation to New Work or Further Work on an Existing Installation ,


Where Design , Construction and Inspection & Testing , is the Responsible of One Person a Certificate with s Single Signature
Declaration in the Form Shown below may Replace the Multiple Signatures Section of Mode Form

“ FOR DESIGN , CONSTRUCTION , INSPECTION & TESTING “

(iv) a Minor Works Certificate will Indicate the Responsibility for Design , Construction , Inspection & Testing
Of the Work Described in Part 4 of the Certificate

(vii) a Periodic Inspection Report will Indicate the Responsibility for the Inspection & Testing of an
Installation within the Extent & Limitations Specified on the Report

(vii) a Schedule of Inspections and a Schedule of Test Results as Required by Part 7 shall be Issued with the Associated
Electrical Installation Certificate or Periodic Inspection Report

(ix) when Making Out and Signing a Form on Behalf of a Company or Other Business Entity ,
Individuals shall State for Whom they are Acting ,

(x) Additional Forms may be Required as Clarification , if needed by No-Technical Person , or in Expansion , for Larger
Or More Complex Installation ,

(xi) the IEE Guidance Note 3 Provides Further Information on Inspection & Testing on Completion and for Periodic Inspections ,

2392-10
Options for Showing Electrical Installation Competence

The Following is Provided as a Guide to Different ways in which in any Electrical Work Undertaking can be Certified ,

(i) if an Approved Certifier of Construction has Carried Out Electrical Work then that Contractor will Provide the Appropriate
Certificate , Duly Completed , for the Council to Verify OR

(ii) if the Electrical Contractor or Electrician is Not an Approved Certifier of Construction then the Appropriate Certificate
Taken from BS-7671 2008 should be Submitted , Duly completed , Together with Evidence of Competency ( i.e. Valid ↔
JIB Card or having Current Membership of an Accredited Registration Scheme Operated by a Recognised Professional
Body e.g. NICEIC or Select or Equivalent Body OR

(iii) if the Electrical Work was Carried Out by a Qualified Electrician , it may be the Case that you will Need to have the
Installation Checked by a Qualified Electrician and the Appropriate Certificate in Accordance Submitted ,
With Evidence of Competency ( i.e. Valid JIB Card / or having Current Membership of an Accredited Registration
Scheme Operated by a Recognised Professional Body e.g. NICEIC or Select OR Equivalent Body ,

Testing Class II Equipment

The test includes:
• physical examination
• insulation test
• flash test (optional)
The first test conducted must be the detailed physical examination. Any faults found should be corrected and defective items replaced.
The first electrical test performed will be the insulation resistance test. If the appliance is double-insulated then the insulation test is carried out between the combined live and neutral pins on the plug and a probe that is applied to the outside of the appliance case. Make sure that the appliance under test is turned on. The resistance reading should be at least 2 M Ohms. If the resistance reading is less than the value you must investigate why. Do not use the appliance until the fault has been cleared.
Testing Class III Equipment
Class III equipment is designed to be supplied by a reduced voltage which is normally 110V. Portable Appliance Testers are usually rated to operate at 240V and manufacturers usually provide each model in two versions to be able to test class III apparatus separately.
APPENDIX 1
BS1363 - 13A plugs, switched and unswitched socket outlets and boxes.
BS2754 - Construction of electrical equipment for protection against electric shock.
BS2769 - Hand-held electric motor-operated tools.
BS3456 - Safety of household and similar electrical appliances.
BS3535 - Specification for safety isolating transformers for industrial and domestic purposes.
BS4343 - Industrial plugs, socket outlets and couplers for AC and DC supplies.
BS4533 - Luminaries’.
BS4743 - Safety requirements for electronic measuring apparatus. (IEC348).
BS5458 - Safety requirements for indicating and recording electrical measuring and their accessories.
BS5850 - Safety of electrically energised office machines. (IEC380).
BS6204 - Safety of data processing equipment. (IEC435). BS6500 - Insulated flexible cords.
BS7002 - Safety of I.T. equipment including business machines. (IEC950).
Note: The IEC reference is the International Electrotechnical Commission "parent" standard. For Appendix 2 & 3 please consult the "Electrical Safety Testing" booklet.

 

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Testing Class I Equipment

The tests include:
• physical examination
• earth bond test - essential
• insulation test - essential
• flash test - optional
• operation test - optional
• power consumption test - optional
A detailed visual inspection should be performed first and any faults corrected. Over 75% of all equipment defects can be found at this first stage. Hazards such as loose cable grips, plugs incorrectly fitted, unsafe cable joints, damaged cable, wrong value fuses or illicit fuses should all be discovered and corrected at this physical inspection stage before electrical tests are commenced.
Before performing the electrical tests, it is important to establish whether the appliance is a light current type. Assume the appliance to be light current if it has a 3 or 5A fuse fitted, if it has a power rating less than 1kW or if the appliance cable is thinner than the normal mains lead. If these criteria apply then the appliance tester will be operated in a different manner. The manufacturers instruction booklet should be referred to.
The first essential test for class 1 appliances is the earth bond test. This test is intended to ensure that the exposed metalwork on the appliance is securely connected to the safe earth potential. During the test a high current (up to 25A) is passed through a circuit comprising the appliance earth conductor of the supply lead, the exposed metal on the appliance and the temporary test lead from the appliance tester. If the exposed metal work is securely connected electrically to the conductor, the resistance of the above circuit will be low. To be acceptable it must be between 0 and 0.1 Ohms (0.5 Ohms for low current appliances). This test must be carried out on all exposed metal work. If the resistance is too high, the protection afforded by earthing will be limited.
If the reading on the appliance tester indicates a high resistance or the fail indicator lights, then this must be investigated. First check the logged value for the equipment. It may be a low current appliance. If the reading is the same as the previous recorded value then this may be accepted (the resistance of thin mains leads may be appreciable e.g. 2.5 metres of 0.5 sq mm cable is itself around 0.1 Ohms). A particularly long lead or extension cable may also have an appreciable resistance. If this is the case get advice as to whether a circuit breaker should be fitted.
Check the security of the connections in the mains plug although this should already have been done during the physical inspection. Do not progress with further tests until this fault has been cleared.
The second essential test for class 1 appliances is the insulation test. This is used to ensure that a breakdown of the insulation cannot occur between any live parts within the appliance and parts of the casing that the user may touch. The appliance tester must be able to deliver a 500V DC test voltage for all loads of 2 Mohms upwards. The test may be performed as many times as you like without causing undue stress to the appliance under test. Note that the test procedure is slightly different for class 1 and class 2 appliances.
The appliance under test is switched on. If the appliance is earthed then the insulation test is carried out between the earth pin and the combined live and neutral pins on the plug. This relies on a satisfactory result for the earth bond test. If the earthing is faulty this test should not be performed as the results would be totally invalid.
Although the essential tests must be carried out in the order described the optional tests may be carried out in any sequence, but the flash test should only be carried by fully trained personnel preferably under workshop conditions. If an appliance has been recently repaired the essential earth bond and insulation test must be repeated first then the optional test can be carried out. The optional tests, although straightforward, can be difficult to interpret and should therefore only be authorised, carried out and interpreted by highly skilled and preferably electrically qualified personnel.

What type of Equipment Should be Tested

The equipment to be tested will normally be constructed in one of 3 basic classes designated Class I, II or III under British Standard 2745. (Class O equipment which has no provision for the earthing of metalwork is of foreign origin and safe only in earth-free zones.
Class I Apparatus is provided with basic insulation. In addition the metalwork is earthed so that it cannot become live in the event of an insulation failure.
Class I Apparatus is the most common type; its safety depends on the integrity of its one layer of insulation and the earth bonding of its metalwork. If there is an insulation fault, the metalwork is entirely dependent on the integrity of the earth bonding if it is not to attain a hazardous voltage. Inspection of the earthing conductors and connections is very important where this type of apparatus is used.
Class IIA (All-insulated) Apparatus has two layers (or equivalent) of insulation, one of which covers or comprises the outer casing so that metalwork cannot be touched. Class IIB (Double-insulated) Apparatus has all exposed metalwork separated from the conductors by two layers of insulation so that the metalwork cannot become live. There is no earth connection and the operator's safety depends on the integrity of the two layers of insulation. The first layer is basic or functional insulation and the second layer is supplementary or protective insulation. In some cases a single insulation layer is allowed if it is mechanically and electrically equivalent to double insulation.
Class II equipment is marked with the symbol (please consult "Electrical Safety Testing" booklet for symbol).
Class III Apparatus operates on safety extra low voltage (SELV) i.e. at a voltage not exceeding 50V AC between conductors or to earth. The apparatus has basic insulation only and unearthed metalwork.
Class III motor operated tools are not widely used in the UK as they are difficult to obtain. They are larger than comparable mains voltage tools and larger cables have to be used to avoid volt drop problems. 50V or 25V handlamps, soldering irons and special purpose heaters are commonly used.
While the isolating transformer provides the essential electrical separation from the mains supply, some users also choose to earth the centre tap of the low voltage winding of the transformer and also earth the exposed metalwork of the apparatus. This is strictly speaking a Class I extra low voltage installation with a line-earth voltage of half the system voltage.
Class III equipment should not be fitted with plugs or connectors of a type standardised for operation at mains voltage.

 

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Priority Equipment and Equipment with Special needs

When instituting a test programme, priority should be given to certain types of equipment whose usage and operational environment mean that they are more likely to give rise to electrical danger. Examples of these include the following:
• Handheld tools such as drills.
• Equipment with long cables which might be easily damaged and those with easily damaged electrical components e.g. floor polishers, vacuum cleaners, desk lamps.
• Equipment with which water is intimately involved e.g. kettles, steam irons, thermostat baths, water stills, electrophoresis apparatus.
• Equipment normally used in a wet or humid place e.g. in kitchens, hot rooms, cold rooms, aquaria, hydraulics laboratories.
• Equipment used in areas where there is a high chance of damage by corrosive chemicals, oils, solvents or sunlight. These are especially liable to damage the insulation.
• Equipment used outdoors.
Extension leads should be treated in a similar fashion to removable mains leads. They should have unique serial numbers and be tested at regular intervals. The following tests are recommended:
1. Resistance of the earth conductor.
2. Insulation resistance testing.
3. Continuity of each conductor.
4. Polarity of phase, neutral and earth connections.
As the length of the extension cable will have an effect on earth resistance, compare the test value with the resistance expected for the particular conductor size. Extension leads are likely to be exposed to a high level of abuse. Visual inspection of the insulation is therefore extremely important as is examination of the terminations to the plug and socket.
Modern low voltage transformers are manufactured to British Standard 3535 which allows either Class I or Class II construction. The transformer should be treated as any other piece or portable equipment. An additional test may be required to ensure that the primary voltage does not appear on the secondary winding. A flash test conducted on a Class I transformer will have additionally proved the insulation between the primary winding and the earthed screen thus ensuring primary/secondary isolation. The flash test conducted on a Class II transformer will not have tested the integrity of the insulating barrier between primary and secondary winding. A high voltage insulation test will therefore be required between the input and the output connections.
Portable Appliance Testers are in themselves items of portable equipment and will therefore require safety testing in accordance with the criteria described elsewhere in this booklet. In addition, the equipment should be subjected to a full certified calibration procedure on an annual basis.
There are some common types of equipment which are not connected to the electrical system by a 13A plug but which are nevertheless the responsibility of the Department. Examples are centrifuges, electron microscopes, X-ray equipment and workshop equipment such as milling machines and lathes. Special arrangements, in some cases with the supplier, will be necessary to deal with these items. The fact that they are not portable (nor indeed readily transportable) may mean that testing can be carried out less frequently but the location and usage does need to be considered.

Frequency of Testing

There are no absolute rules regarding how often an item of electrical equipment should be tested. The Health and Safety Executive Guidance Notes on the safety of electrical apparatus advise "regular testing" and this is generally interpreted as a requirement for annual testing. However, circumstances and conditions of use will vary and it is therefore up to Departments to assess the conditions of use of each piece of apparatus to determine, using the following guidelines, the test regime which is most appropriate.
The criteria which should be used to assess the need for testing the equipment includes the following:
1. Whether the equipment is portable i.e. Is it always used held in the hand (as opposed to being transportable) so that there is a greater likelihood of the apparatus being dropped while is use as opposed to being permanently installed on a desk.
2. Whether its usage is continuous or infrequent and whether the nature of its task is inherently rough.
3. The age of the equipment.
4. If the equipment is regularly moved or transported and by what means.
5. The overall competence of personnel using the equipment.
6. The environment of usage i.e. indoors v outdoors, hazardous atmospheres, likelihood of exposure to water, solvents, oils etc.
7. The results of previous tests.
Based on these criteria some suggested test periods are as follows:
Handheld portable tools should be tested every 6 months.
Equipment identified as being a priority should be tested not less than once every 12 months.At least 25% of double insulated (class II) equipment should be tested each year with the aim of testing each piece of this type of apparatus every four years.
Within this general framework, most equipment in laboratories or workshops should be tested at intervals of between 12 and 24 months, depending on the 7 criteria listed above. Most equipment in offices, libraries and similar accommodation should be tested every 24-36 months.

Test Precautions

The safety test programme consists of each item of apparatus receiving a visual inspection, essential tests (earth bond and insulation) and in some cases, additional tests such as flash, operational and earth leakage tests. Of the essential tests, the insulation test is always carried out but the earth bond test in only performed on class 1 appliances. The optional tests should be performed at the discretion of the competent person in charge, perhaps because there is some reason to think the appliance may become unsafe. Some optional tests should not be carried out more than is necessary as they may weaken the insulation of the appliance.
The following precautions are necessary during the testing of the apparatus:
1. Precautions for Essential Tests
• Check the test results sheet and identify the class of the appliance, its operating voltage and any special precautions which should be observed.
• Check that the environment in which the tests are to be performed is free from hazards, e.g. the earth bond test or insulation test may produce a spark which would ignite flammable vapours or fine dust.
• Disconnect all other equipment from the appliance under test. This not only guards against potential hazards but also against spurious results.
• Ensure that no one including yourself touches the appliance during testing. If the appliance is faulty they may receive an electric shock.
• Ensure that any test equipment is plugged into a proper earthed mains supply.
• Some tests require that the appliance under test is switched on. You may need to clamp the on/off button on some appliances. Ensure that no damage is possible due to the operation of the appliance e.g. an electric drill would need to be suitable secured during the test.
• Stop testing immediately an appliance fails one particular test. Do not go on to the next test because the appliance may be in a dangerous state.
• Always do the tests in order of, first, visual inspection then the earth bond test for class 1 appliances followed by the insulation tests.
2. Precautions for Optional Tests
All the precautions above apply to the optional tests plus those give below:
• Check the initial test results and ensure that any given test may be applied to the appliance. Electronic equipment may use semi-conductor devices and interference suppressors which will not withstand certain tests. The equipment manufacturer should be asked to define which tests may not be undertaken. Motors such as inductively stalled types will not pass the low voltage load test.
• Take particular care when performing a flash test as the very high voltages can be dangerous. It is best to have a second person on hand so that if you receive a shock, they can remove the power and resuscitate you.

4. After an initial physical evaluation, electrical tests are carried out to ensure the continued safety of each appliance. The test results are logged. Equipment which fails a safety test is withdrawn from use, the cause investigated and it is either repaired or replaced.

'Wattage' of Equipment = Fuse Rating
'Wattage' of Equipment Fuse Rating
Up to 600 Watts 3 Amps
Between 600 Watts and 1000 Watts (1KW) 5 Amps
Between 1KW and 3KW (3000 Watts) 13 Amps

Equipment that is rarely moved and is not at risk of damage (e.g. computers) is likely to be low risk and requires less frequent inspection than equipment that is frequently moved, might be used in a damp environment (e.g. kettles, water baths) or may be subject to damage.
Equipment used in an office environment is rarely of the type that would be considered high risk. High risk equipment includes equipment such as portable electrical hand tools.
As the title visual inspection implies, all you really need to do is look closely at the equipment. More than 90% of equipment faults can be found by visual inspection.

Current Fire Extinguisher Colour Codes ( New EEC Colures / BS- )

(1) Just ↔ Red ( Water Only ) ↔ Water
● Paper , Wood , Textiles & Solid Materials Fires

(2) Red ( With Blue Mark on Red Body ) ↔ Powder
● Liquid , Electrical , Wood , Paper & Textile Fires

(3) Red ( With Cream Mark on Red Body ) ↔ AFFF Foam
● Liquid , Paper , Wood , Textile Fires

(4) Red ( With Black Mark on Red Body ) PS. Do Not Hold Horn When Operating ↔ Carbon Dioxide ( CO2 )
● Liquid , Electrical Fires ,

N.B (a) Both Colour Codes are Still in Use ,
(b) a New Class F Extinguisher is now Available for Cooking Oil & Fat Fires ,

 

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That’s how to Keep the Reaper at Bay !!!!!

Isolation

(1) Remove the Load from the Circuit to be Isolated
(2) Open the Isolator and Lock Off
(3) Prove the “ Approved Voltage Tester “ on a Know Source ( Proving Unit )
(4) Test the Circuit to Confirm as “ Dead “
(5) Re-Prove the “ Approved Voltage Tester “ on the Proving Unit
(6) Fit Warning Notices at the Point of Isolation
(7) Keep the Key in your Pocket Ensuring Only you can Re-Energise the Circuit

The Source of Supply may Not have Means of Locking Off Afforded to it ,
If that is the Case , Look for Alternatives , Lock the Whole Switch Room Off if Necessary ,
Physically Disconnect the Supply , if you Have to Leave a Lookout at the Point of Isolation ,

Inform People of What you are Doing ,

→ → Your Safety is Your Own Responsibility ← ←

The Above May or Not be Factual ,
The Point is Every Time an Electrician is Electrocuted it is Because the Correct “ Isolation Procedure “ has Not been Followed ,

Continuity of Protective Conductors
612.2.1
Instrument ( Continuity Tester ) Low Ohms
No Load Voltage between 4 & 24V d.c. or a.c.
Short-Circuit Current of Not Less than 200mA Ia / Ief ( Exposed Conductive Parts )

On New Installations’ or where the Supply may be Isolated then the Protective & Bonding Conductors’ May be Disconnected for the Duration of the Test
Where this is Not Possible Earth Loop Impedance Tests may be Made to Verify Continuity ,
Instrument , Main Protective Bonding Conductor , Cables Résistance should Not Exceed 0.05Ω
The Résistance of a Typical Supplementary Protective Bonding Conductor Should Not Exceed ( R = 50 V ÷ Ia )

411.8.3
“ Requirements for Fault Protection “

Where Fault Protection is Provided by an RCD , the Product of the Rated Residual Operating Current ( I∆n )
In Amperes and the Earth Fault Loop Impedance in Ohms shall Not Exceed 50 V

“ Circuit Protective Conductor “
Does Not Rise Above Earth Potential More than 50V ,

Overcurrent Protective Device is Used , Zs / Uo ÷ Ia ( 230 ÷ Amp = Zs )

Damage Under Earth Fault Conditions “ Ohms “ Ia / Uo ÷ Zs ( 230 ÷ Zs = Amp )

Requirements Relating to Items Required for Typical Distribution Board Schedule 514.9

Domestic Electrician Installation of Cables , 521.10.1 , Meter Tails ( IP4X )
434.3 / (iv) Csa 514.3 530.3.4 - Consumers Controlgear ,

527.2.1 / FireFoam ( fire-resistance

120.3
Any Intended Departure from these Parts Requires Special Consideration by the Designer of the Installation and Shall be
Noted on the Electrical Installation Certificate Specified in Part 6 ( Inspection & Testing )
The Resulting Degree of Safety of the Installation shall be Not Less than Obtained by Compliance with the Regulations ,

132.13
Documentation for the Electrical Installation
Every Electrical Installation shall be Provided with Appropriate Documentation , Including that Required by
Regulation 514.9 , Requirements Relating to Items Required for Typical Distribution Board Schedule , Part 6 & where Applicable Part 7

134.1.7
Where Necessary for Safety Purposes , Suitable Warning Signs and / or Notices shall be Provided

610.1 Initial Verification ( Testing for New Electrical Installation Work )
Every Installation shall , During Erection and on Completion before being put into Service , be Inspected & Tested to Verify ,
So far as is Reasonably Practicable , that the Requirements of the Regulations have be Met

134.2.1
Initial Verification ( Initial Inspection & Testing )
During Erection and on Completion of an Installation or an Addition or Alteration to an Installation ,
And before it is put into Service , Appropriate Inspection & Testing shall be Carried Out by Competent Persons to Verify
That the Requirements of this Standard has been Met ,

( Appropriate Certification shall be Issued in Accordance with Sec 631

631.1
Upon Completion of Verification of a New Installation or Changes to an Existing Installation , an Electrical Installation Certificate
( based on model given in App 6 p-331 , shall be Provided , Such Documentation shall Include Details of the Extent of the
Installation Covered by the Certificate , Together with a Record of the Installation and the Results of Testing
( Schedule of Inspection and Electrical Installation Certificate )

Paperwork that should be Issued on Completion of New Installations ,
Schedule of Test Results , Schedule of Inspection & Electrical Installation Certificate

632 Initial Verification
632.1
Following the Initial Verification Required by Chapter 61 p-155 an Electrical Installation Certificate together with a
Schedule of Inspection , Schedule of Test Results , shall be given to the Person Ordering the work

632.2
The Schedule of Test Results shall Identify Every Circuit , Including its Related Protective Device(s) and shall
Record the Results of the Appropriate Tests and Measurements ,
632.4
Defects or Omissions Revealed During Inspection & Testing of the Installation Work Covered by the Certificate shall be Made
Good before the Certificate is Issued , ← ←

611 Inspection
611.1 Inspection shall Precede Testing and shall Normally be Done with that Part of the Installation Under Inspection Disconnected
From the Supply , ( That Appropriate form of Disconnection is Isolation )

Regulation 12 Electricity at Work Regulations 1989

( Maximum Demand & Diversity should be Determined before an Installation is to begin ) ←←

311 Maximum Demand & Diversity
311.1 For Economic & Reliable Design , the Maximum Demand of an Installation shall be Assessed
In Determining the Maximum Demand of an Installation or Part thereof , Diversity may be taken into Account ,

314.4
Where an Installation Comprises more than One Final Circuit , each Final Circuit shall be Connected to a Separate Way
In a Distribution Board , the Wiring of each Final Circuit shall be Electrically Separate from that of Every Other Final Circuit ,
So as to Prevent the Indirect Energizing of a Final Circuit Intended to be Isolated ,
( This is a requirement in Domestic ) ←← Part P ,