***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