***Cont../ Useful Information for Electricians & Apprentices***

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Re: ***Cont../ Useful Information for Electricians’ & Apprentices***

559.6.1.5. Fixing of the Luminaries.

Thevast majority of light fittings are installed above head height . so clearly itis Important that the fittings are secure BS-7671 requires that the fixing for somethingas Light as a Pendent Set has to be capable ofsupporting a Mass of 5kg .

 

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Re: ***Cont../ Useful Information for Electricians’ & Apprentices***

SorryI have to break this into two parts .

Firstlyyou should be aware there are 3 Methods / Consumer Units available . [ I will try & open the Examples for you]

Knowledgeis the greatest arsenal we have .

Thereare Single Load – RCD .
Split Load RCD & RCBO

► Just a Point to Note here . The RCD is not just a Manually OperatedInsolating Switch – Sensitive Safety Device which cuts OFFin fraction of a second if it Senses an Earth Fault.
► Question ? it is NotPractical to fit One RCD to protect the Whole House . !! Why Tripping .
Ido want to open a mine field here . “ Division of Installation “
314.Every Installation shall be divided into Circuits . as necessary to ? (i) Avoidhazards & minimize inconvenience in the event of a Fault . “ So “ One RCDat the Main incoming does not meet this criteria . ( iv)

Example)- 8 – Way 30mA DPRCD … ( 1 x RCD) IP2X .
BS-EN 60439-3……(British Standards )The country hasStandards for & reasonNOT made in China
100 Amp .
Example)- 6A ( SP) type B / MCB …. 40A ( SP ) type B / MCB → This could be used for a Shower& Power Circuit
( SP ) meaning -Single – Pole ( Line Only )
( DP ) meaning -Double – Pole ( Line& Neutral Only ) with ( L & N – Earth must be Added )

Asa Young Designer this must seem daunting . Don’t Worry
gointo the Forum& Ask Questions . We wereApprentices at one Time . Yeah .

Meaning!! BS-EN 60439-3
Regulation530.3.4. ( Consumer’s Controlgear ) Learning Curve .
Foran Installation with a 230V Single phase supplyrated up to 100A that is under the control of Ordinary Persons . Switchgear & Controlgearassemblies shall either comply with BS-EN 60439-3& Regulation 432.1. or be a Consumer Unit incorporating components &Protective devices specified by the Manufacturer complying with BS-EN 60439-3 . including the conditional Short-circuit testdescribed in Annex ZA of BS-EN 60439-3 .

Asa young Designer . if we look in O.S.G. p/17 – 2.2.5
Consumer’sControlgear
AConsumer Unit ( to BS-EN 60439-3- Annex ZA ) is for use on Single-phase Installation’s up to ( 100A ) itincludes . 530.3.4
•A Double pole isolator .
Fuses. circuit breakers or RCBOs for protection against Overload & Faultcurrents . &
•RCDs for Additional Protection against Electric Shock . ( Anything that moves . RCD it & Earth it )RCD / RCBO – remember that an RCBO is RCD/MCB .

Designer/ Electrician :
Whenspecifying Enclosures & their Accessories . it is Important to bear in mindExisting Standards to which the Products are Manufactured&/or Tested .
TheStandards are Written to Ensure CONFORMITY .Integration with other Products & Safety ofPersons & Equipment.

Thisto keep in Mind -
Overload.
ShortCircuit ↔ ( Fault Current )
EarthFault .
Wewill go there an other day { PS am not asking you to take this in all in One .am opening your eyes to things as a Young Designer }

IP4X . Rating’s on Consumer Units . “ Meaning “
RedCover - The Only Requirement of the Regulations ( BS-7671:2008) – 416.2.2. forthe Initiated ↔ ( is the TOP SURFACE of theEnclose ) IP4X/ IPXXD
(with Apertures Intended to exclude Particles of Greater than ( 1mm diameter ) To stop Dirt falling into the Enclosure

IP2X . Rating’s on Consumer Units . “ Meaning “
TheBottom & Sides ofthe Enclosures Only need to be IPXXB or IP2X ( The Testis made with a Metallic British Standard finger Test – 12.5mm diameter .
“Plain English “ FullPenetration into the Enclosure is NOT Allowed . Let ask you this ??

[Both Joints of the finger may be Bent through 90° degrees with respect to theAxis of the Finger but in ONE & the SAME direction ]
AmUsing the Wording - Finger is PushedWithout UNDUEFORCE . So there you have it . in One
Young Apprentices this is Only Guidance

 

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Re: ***Cont../ Useful Information for Electricians’ & Apprentices***

ConsumerUnit(s)
MCBs/ RCBOs are sitting on the bottom off Buzz Bar “ Copper Bar “ Feeds Mainspower to MCBs / RCBOs
MCBs/ RCBOs are Clipped onto a DIN rail

Justa point to Note :
Wecan get – MCBs Colour coded dolly’s allow quick Visual Identification of Ratings .now – BS-EN 60898

Whatis a Split Load .
100A Main Isolator → outgoingways ?? MCB / RCBOs ( 4) Non-RCD side
RCD30mA – 80A → MCBs ( 4 ) RCD side - ( Additional Protection ) 30mA RCD Basic Protection / Touching Live Parts . ARCD is a Fixed Equipment
RCD30mA – 80A → MCBs ( 4 ) RCD side

TestingRCD buttons – Do Not Hold the button more than 2 seconds [ You are crating aFault in the RCD for Testing Purposes]

RCDs- 0° & 180° deg ( ½ - 1x – 5x )times ( This sign is for Alternating Current ≈ A.C. ) Marked on the RCD - 230V . SinglePhase

Donot Overlook – as a Tester that ( When all the Tests are Complete the Testbutton to Ensure this Functions Correctly )

Pointto Note . The 17[SUP]th[/SUP] Edition tells usto test the Button on an RCD “ But Not “Before or After Testing RCD .

Megger1552 )- an RCD Tester is an ElectronicDevice which draws current from the Supply for it’s Operation .
Thiscurrent is usually of the Order of a few mA s which is taken from Line & Neutral of the Supply under Test(s) Single-phase

For-&-s Purposes Exams’ ?? TestingResidual Current Devices ( RCD )

-&-s– i) BS-200mS ……………….. Older
-&-s– ii) BS-EN 300mS

RCDto Achieve Automatic Disconnection in the case of a Fault . ( If )

411.3.2.1.
Requires. “ in most cases “ that a Protective Device ( MCB ) shall Interrupt the Supply to a Line Conductor of a Circuit or Equipment in the eventof a Fault of Negligible Impedance between / Line Conductor& part or a Protective Conductor for the Circuit or Equipment within theAppropriate Required Disconnection Time .

“Plain English “
2392-10- TN- 0.4 seconds 41.1 – 411.3.2.2. tells us The maximum Disconnection – 41.1. shallb e applied to final circuits NOT EXCEEDING 32A [Domestic Installation(s) ]

 

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Re: ***Cont../ Useful Information for Electricians’ & Apprentices***

Working my way Around the 17[SUP]th[/SUP] Edition :

555)- Transformers .

Thereare Only three Regulation(s) . 555.1.1. to 555.1.3. relating to Transformers asItems of Equipment .
Throughtheir Installation . subject to the generality of BS-7671:2008

Thefirst > Autotransformers & Step-up-Transformers
Autotransformers& requires where such transformer is employed & is connected to acircuit with a Neutral conductor that conductormust be connected to the common terminal of the Winding

Regulation555.1.2. Precludes .
Theconnection of Step-up Autotransformers to an ( IT ) system . in all cases wherea Step-up Transformer is used - Regulation555.1.3.calls for a Linked Switch to disconnectall Live Conductor(s) Line & Neutral – Simultaneously fromthe Supply ( DP )

 

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Working my way around the 17[SUP]th[/SUP] Edition .

Principal Requirements for Devices for General Emergency Switching

Regulation537.4.2.3.
( Requirement )- Where practical . non-automatic device
Regulation537.4.1.2.
( Requirement )- Switching of all the live conductors( Except the Neutral where excused by Regulation 537.1.2. ) is required if there is a Risk of Electric Shock
Regulation537.4.2.1.
( Requirement )- Capableof Switching Load Current .
Regulation537.4.2.1.
( Requirement )- In the case of Motor(s) . Must be capable of switching stalled-rotor current .
Regulation537.4.1.3.
( Requirement )- To be Single-ActionDevice .
Regulation537.4.2.7.
( Requirement )- Identified as to purpose ( Appropriately Labelled )
Regulation537.4.1.3.
( Requirement )- Device to act as directly as Possible onCircuit concerned
Regulation537.4.2.5.
( Requirement )- Suitably Located
Regulation537.4.2.3.
( Requirement )- If device is used to operatecontactor controlling the circuit . Switching is requiredto de-energize coil . or another technique of suitable reliability mustbe used
Regulation537.4.2.6.
( Requirement )- If Push Button. must be the Latching OFF TYPE
Regulation537.4.2.8.
( Requirement )- Plug &Socket-outletNOTACCEPTABLE
Regulation537.4.2.4.
( Requirement )- Operating Knob . Lever or Button . PERFERABLY Colour RED .

I have shorted some stuff in wording .

 

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Young Apprentices .

Wording– Two Words in different contents ( EmergencyStopping ) as opposed to ( Emergency Switching )

 

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LearningCurve Here .

Emergency Switching )- devices must “ Regulation 537.4.2.1. “ must be capable of Interrupting the Supply ON LOAD
Plain English – The Full Load Current )

Emergency Switching )- requirements apply to ALL EQUIPMENT where a HAZARD may be EXPECTED in NORMAL USE.
Plain English – Located in a ReadilyAccessible Position & Operator is not put in DANGR - that could be you one day

 

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Difference in Wording

Regulation 537.4.1.3. – Demands that an Emergency Switch Arrangement is such that onesingle action will Interrupt the appropriate supply .
Regulation 537.4.1.3. – Means for Emergency Switching shall act as directly as possible onthe appropriate supply conductors .

 

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Regulation(s)Table 53.2 ( Restriction on Use as Isolator ) Note 3 bottom of page – read

Fused ConnectionUnit : ( FCU ) Yes / Note 3
Whatthe Regs are saying – Suitable for OFF LOAD operation Only You will be . Isolationof current using equipment . ( Fuse in Pocket ????? )

2392-10)- keep in mind you may have a TT System Except where Neutral requiresIsolation .
PS – I have been known to use lock off Spurs Unit / padlock

 

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Testing

IsolationRequirements relating to System Types

TN-C ( Number of Phases – Single – Phase ↔ ( Isolation required for ) Line Only
TN-C ( Number ofPhases – Three – Phase ↔ ( Isolationrequired for ) Three Line(s) Only

TN-C–S ( Number of Phases – Single – Phase ↔ ( Isolation required for ) Line Only
TN-C–S ( Number of Phases – Three – Phase ↔ ( Isolation required for ) Three Line(s) Only

TN-S ( Number of Phases – Single – Phase ↔ ( Isolation required for ) Line Only
TN-S ( Number of Phases – Three – Phase ↔ ( Isolation required for ) Three Line(s) Only

TT( Number of Phases – Single – Phase ↔ (Isolation required for ) Line & Neutral
TT( Number of Phases – Three – Phase ↔ (Isolation required for ) Three Line(s) & Neutral

IT( Number of Phases – Single – Phase ↔ (Isolation required for ) Line& Neutral
IT( Number of Phases – Three – Phase ↔ (Isolation required for ) Three Line(s) & Neutral

 

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UsefulJunk :

IP56Protection .
Eachdigit in an ( IP ) Ingress Protection rating denotes résistance to Dust &Water . IP56 rating breakdown as follows .

IP- Ingress Protection
(5 ) Dustproof to sawdust . Dust & other Small Partials .
(6 ) Waterproof to Strong Jets of water .from any Direction .
Gardens. Workplaces / Shops . Industry . Farm buildings . Swimming pools . Squash courts . Gyms . ETC

IP- Ingress Protection
IP66. Offers total Dust Ingress Protection . & is protected againstHigh-Pressure Jets from any Direction .

 

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UsefulJunk bulbs

whydoes light bulbs blow ?
Whydoes the Circuit Breaker trip ?

TheCircuit Breaker does not trip because a broken filament has dropped onto a leadout wire as some people would have you believe but is due to the gas orfilament in the lamp becoming Ionised . The hightemperature & large electric field can cause the gas to go into a CONDUTIVE STATE & the plasma will spread until it SHORTS OUT the lead wires

 

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Useful Junk “ Wording “ The Humble light switch .

“ Gang“
Means there are more than One Switch on a singlefitting .
“ Way“
Means that the switches will operate from two or morelocations . i.e.

•What isthe current rating of a Switch ? The maximum Currenta Switch is designed to Carry !
•What isthe Voltage rating of a switch ? The maximumVoltage allowable in the circuit in which the switch is installed . 230V

 

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Testing - ►► A common trick question in any ExamPaper(s) 2391-10 / 2392-10 -&-s

►►►►► ( Making you aware - The x5 test is ( N/A )for Anything BIGGER than ( 30mA ) RCD / ADS ☜
Testcurrent at )- 5 I∆n . The maximum testtime not be longer than )- 40mS “ Answer“ Device shouldoperate in less than 40mS

( 500 is x5 ) I will give it its full title )- x5 I∆n ≤ 30mA Deviceshould operate in less than 40mS -&-sOut of this . there three Questions in here

 

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The point of all this is ( ThisForum will help you as much as possible 99.9% ) We all Love -&-s . Yeah

2392-10Question ?? -&-s

Asa Competent Person ) Tester to be .-&-s are judging you on this matter .

Amusing the Wording ( Testing – full stop )

ARCD must be Tested . ( No excuses )The Regulations are telling us . Therequirement(s) are stated in thefollowing Regulation ??? Where !!

TheEffectiveness of the RCD must be Verified by a TEST SIMULATING an APPROPRATEFAULT CONDITION ) – Full stop “ Push the Button “ ◄◄

Regulation 612.13 )- Functional Testing ◄◄


► Do not Mix up the two Regulation(s) 612.13 )- 612.10 ) ← ← ← ← ← ← ← ← ← ← ← ← ← ← ←


(Megger 1552 – out at this stage ) Regulation 612.10– Wording on this matter is.

( Visual Inspection is the First line of Defence ) Eyes

AdditionalProtection ( ADS ) The Verification of the Effectiveness of the measuresapplied for Additional Protection is Fulfilled by VISUALINSPECTION & TEST

RCDs shall be VERIFIED using SUITABLE TESTEQUIPMENT According to BS-EN 61557-6 …… ( Megger 1552 – out at this stage )
Thiswill take you to Regulation 612.1 . p/157
MeasuringInstruments & Monitoring Equipment & Methods shall be chosen inAccordance with the relevant parts of BS-EN 61557.

Youwill be Complying with Chapter 41 ( will be met )
Chapter41 – Protection against Electric Shock (Plain English is the RCD working to BritishStandard ? is it Safe . The Manufacture say there have tested it – all you doing covering you But . the other way of looking at this is “ The public will be Safe “

I don’twant to Harp on .

Remember“ RCDs – BS – 200mS -&-s ………………….. Still in Use
Remember“ RCDs – BS - EN 300mS -&-s

 

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TestInstrument :

Whatthe Regulation(s) are saying – The Test instrument used to Test RCDs should becapable of applying the FULL RANGE of TEST CURRENT ( BS-EN 61557 )

-&-s Question ?? The Test Current should be APPLIED for NO longerthan ( 2 seconds ) Your Answer

Must dash of to the Wholesalers now . Amber

 

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Justa point to Note here : RCDs Range of Tests

Whilethe following Tests are NOT a Specific requirement of BS-7671:2008 . it is recommended that they are carried out

Regulation(s)Table 61. p/158

( IR ) Insulation Résistance

≥ 0.5MΩ for SELV & PELV with D.C. you Test voltage of 250V -&-s 100%
≥ 1.0MΩ for systems up to & including 500V with a D.C. testvoltage of 500V &-s 100%

Workingmy why around the Regulations .

i)– RCD Table . performance criteria for RCDs to BS-EN 61008-1 & BS-EN 61009-1

Regulations:
Table3A . p/243

RCDswhich are identified in Two Main groups or Types of Delay .

Without time delay ( Classedas General Use )
With time delay ( Classed asType S for selectivity )

A 300mA RCD – is Only intended for Equipment & Fireprotection . -&-s ( Fireprotection )

Table( 12A ) P/358
ForDesign purposes )- “ Informative “ wecan class this as . Voltage Drop Table (Maximum 3% Lighting / Maximum 5% forother uses when the circuit is supplied from a public Low Voltage DistributionSystem

Calculations)- 3% of 230V = 6.9V ….. 3x 230V ÷ 100 = 6.9V
Calculations)- 5% of 230V = 11.5V ….. 5 x 230V ÷ 100 = 11.5V

If-&-s was to ask you a Question )- What is the Maximum Volt drop on aLighting Circuit ?? 5%

Apprentices. Designer(s) in the Making

Table41.1 - what the Regulations are sayingis )- Maximum Disconnection Time . 2392-10
TN- ( 120V < Uo ≤ 230V ) 0.4 seconds
TT-( 120V < Uo ≤ 230V ) 0.2 seconds ( PS now the catch .411.3.2.2. – Final Circuits’ NOTEXCEEDING 32A ◄◄◄ -&-s . this willgo around
( Final Circuit . is different from Ring Final Circuit (s) still NOTEXCEEDING 32A ◄◄◄ Watch their Wording .

Example)- Maximum Disconnection Times . Permittedby the 17[SUP]th[/SUP] Edition – for A.C. circuits’ of ( Nominal Voltage (Uo) 230V to Earth .
( 0.2s ) ( 0.4s ) ( 1s ) & ( 5s ) → ( 0.4 s being the most common inTN- systems – 0.2s in TT )

Apprentices – Regulations p/35 Symbols used in the Regulations ( Uo – Nominal a.c. rms Voltage to Earth . ( V ) … 41.1 . MaximumDisconnection times .

Designing.
41.2 to 41.5 )- Values for Maximum Earth Fault Loop Impedance ( Zs )
Designing.
41.5)- Providing Maximum Earth Fault Loop Impedance ( Zs ) values for RCD
Designing.
p/103- 52.1 )- Providing maximum operating temperaturesfor type of cable Insulation .
Thermoplastic / 70°C ) Temperature limit ↔ Thermosetting / 90°C ) Temperature limit
90°C) Temperature limit ( b)
Wherea conductor operates at a temperature exceeding 70°C it shall be ascertainedthat the equipment connected to the conductor is suitable for the resulting temperatureat the connection .
Designing.
p/104– 52.2 )- Cable surrounded by Thermal Insulation . O.S.G. P/125 Table 6B
Testing purposes . p/117 – 53.2
Guidanceon the selection of protective ( Isolation & Switching Devices )

BS-EN 61009-1 .. General RCD
BS-EN 61008-1 .. General RCD

BS-EN 61008-1 ( RCCBs ) General
BS-EN 61009-1 ( RCBOs ) General

BS-4293 ( RCCBs ) General
BS-7288 ( SRCDs ) General

BS-EN 61008-1 ( RCCBs ) Delay ( S )
BS-EN 61009-1 ( RCBOs ) Delay ( S )
BS-4293 ( RCCBs ) Delay ( S )

RCD)- 0.5I∆n Test should also be carried out ( Tocheck for Unwanted Tripping )

 

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Apprentices. “ Reasons “

AdditionalProtection . the 17[SUP]th[/SUP] Edition make a good point here ?? ( ADS ) using there Words Additional Protection Ring Final Circuit 30mA = 40mS

Inthe UK they Sell Electrical Equipment ( ghd – HairTongs £ 100 pounds plus ) Theseconversion plugs enable ( 2 – pin ) Europlugs to be connected to a standard UK 13A Socket outlet . inthe UKthey do not have a Fuse in the conversion plugs ( so there relaying on ( ADS )

Made in China – 50 / 60 Hz - 150W
Your Mans an Electrician (this is the second pair of ghd – my good ladyhas came home with the cable insulation has melted away in the middle of thecable ) Yes I can fix them ! right in the bin

 

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2392-10/ Leaning Curve .

Regulation536.2. Selectivity between Overcurrent Protective Devices . MCBs

Discrimination:

Whereselectivity between Overcurrent Protective Devices isnecessary to prevent Danger & where required for proper functioning of theInstallation .
( ManufacturersInstructions shall be taken into Account )

Regulation536.2. – “ Plain English “ Regulations is Demandingt hat .

Discrimination)- relates to all Faults . Short circuits . Faults between Line conductors & or Line to Earth Faults .

Regulation536.3. Selectivity between RCDs

Where selectivity between RCD is necessary to prevent Danger & where required forproper functioning of the Installation .
( ManufacturersInstructions shall be taken into Account )“Plain English “Regulations is Demanding that .

 

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O.S.G.– Table 1A .
Currentdemand to be assumed for points of Utilisation & Current using Equipment .

Allother Stationary Equipment . British Standard rated current . or normal current .
( Consultthe Manufactures & / or the Standard & / or ratingplate )