sub main

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dan.

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if adding a sub main with say 3 new circuits. is it classed as just 1 new circuit and zs etc taken from say the ring circuit or should all 3 new circuits be on the cert plus the new cable to the sub main??

 
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Hi Dan,

yes mate, you need to record it down as 4 circuits on your EIC ( Electrical installtion Certificate. I would record submain as cct 1, then your other ccts to follow.

 
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Sorry should of said record your ccts on the " schedule of test results" sheet, which accompanies your EIC and schedule of inspections.

Guiness DrinkGuiness DrinkGuiness Drink Think I've had one too many tonight:)

 
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With a sub main you will be issuing an EIC with one schedule of inspections and 2 schedule of tests.

On the first schedule of tests you will have any new circuits that you have run from the main DB (thats your sub main) and on the second schedule of tests you will have all your circuits fed from your sub DB (Zs on the sub db schedule is Zdb - not the origin readings)

 

steptoe

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And dont forget, with the 17th edition the max disconnection times for the sub main is 5 sec but 0.4 for all the finals.
surely that depends on the installation among other things,

not being pedantic, just dont want people taking that as a free for all on a 5sec disconnection time.

 

steptoe

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well how is the cable being protected?

what is the circuit rating?

no mention of RCD anywhere, or cable type, SWA/T&E etc.

be a bit like burying unprotected tails in the wall, and Im sure we already had this topic.

 
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You are wrong. If a cable is feeding a secondary board, then it cant be a final circuit, can it ? The 17th edition states any final circuit now must have a max disconnection time of 0.4 sec (the 5 sec has been dropped), where as a sub-main can have a max of 5.0. Don't ask me which reg No this is today, someone else can look it up.

 
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Reg 411.3.2.3 Its correct term is a distribution circuit, not sub-main as i previously refered to. I also have penciled in that to be a distribution circuit, this must be 32A or over. Also reg 411.3.2.2 refers to Table 41.1 which lists disconnection times for final circuits.

On a TT system a distribution circuit must have a max 1 sec disconnection time

 

dan.

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ok ok calm down calm down:^O

im running 10mm xple swa protected by a 50amp mcb on the non rcd side of the main board.submain has rcd for sockets and heating and an rcbo for the lighting,think i got it all covered, all zs are well below max, insulation is 500+ all round. so if the distribution circuit(swa) has a 5 secs disconnection time how do i know its right if it has no rcd to check? assume that because the zs are well within max limits (0.48 max is 0.96)it will disconnect within 5 seconds??

 

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