Does this setup contravene any regs or is it ok?

Wes1000 · Aug 30, 2018

I’ve just done a large job where I fitted a double stack board (23 ways) and by the time I’d finished we only had two spare ways left in the board. So I thought that I’d free up one more by moving the lighting circuit for the loft on to the lobby lighting circuit at the CCU so both circuits are now on the one 6A MCB. Other than that they are totally separate. They also only contain one light for the loft and two lights for the lobby (all LED’s)

To me this is no different from taking the supply from the last lobby light to the loft and actually might make it easier to find a fault if you could separate it at the board rather than mess about behind down lights.

All was good until I decided to use this job for my Stroma visit.....
I was told that in no way can I do this and I need to correct it or it will go down as a non conformity. After arguing the point for 10 minuets I gave in and put the other MCB in and moved the loft light on to its own circuit and all was peaceful again.

Who’s right here?

123 · Aug 30, 2018

Given it's a Stroma visit, I assume it's domestic?
I'd have left it as it was with 2 spare ways. But I don't see an issue with what you did?

Did they give you a reason as to why?

Wes1000 · Aug 30, 2018

Yes it’s a domestic, new installation in a building conversion.

He just said the regs state every circuit has to be contested to a separate breaker. Now that is true re; reg no. 314.4 but my argument was that as soon as I connected the two together this becomes a single circuit. This is how I read the definition of circuit on page 28 in the definition section of the regs.

I don’t have a problem with moving it back, apart from I was told I was wrong to combine it.

I hate it when I’m wrong and the less it happens the better!

Deleted member 26818 · Aug 30, 2018

Yes every circuit must be connected to a separate way in a DB.
TEs the definition of a circuit is an assemble of electrical equipment supplied from the same origin and protected against overcurrent by the same device or devices.
If I were going to knock the design back, I would choose dividing the installation into circuits to avoid danger and minimise inconvenience in the event of a fault, and facilitating safe inspection, testing and maintenance.

Ian1981 · Aug 30, 2018

He’s being a jobsworth in my opinion

Nigel · Aug 30, 2018

He is correct and has backed it up with a Reg number.

How would you record Zs etc on the cert with two finals coming from one MCB?

SparkyChick · Aug 30, 2018

So how is this any different from say connecting a spur to a ring final from the MCB? Or installing say some hardwired smokes and taking a supply cable from a lighting MCB?

You're not wrong, the assessor is just being a super picky d1ck!

One, two, three, four cables leaving an MCB... it's not the cables that define what a particular circuit is, it's the MCB labelling. If it says Lobby and Attic Lighting, and it has one cable going up to the attic and one to the lobby, then whats the problem?

How would you record the Zs... you'd do what you do for any other circuit... test at each point and record the highest value.

LankyWill · Aug 30, 2018

essex said:
He is correct and has backed it up with a Reg number.

How would you record Zs etc on the cert with two finals coming from one MCB?

Record the highest and make sure the other falls within values, it’s just common sense.

Octopus · Aug 30, 2018

It sounds like westward10 was your assessor,,,,, he’s wrong.

Ian1981 · Aug 30, 2018

Murdoch said:
It sounds like westward10 was your assessor,,,,, he’s wrong.

Now you started something

Nigel · Aug 30, 2018

LankyWill said:
Record the highest and make sure the other falls within values, it’s just common sense.

Poor practice. There are two circuits and the results should be recorded seperatly.

SparkyChick · Aug 30, 2018

essex said:
Poor practice. There are two circuits and the results should be recorded seperatly.

As @spinlondon pointed out, the definition of circuit is:-

"An assembly of electrical equipment supplied from the same origin and protected against overcurrent by the same protective device(s)"

To list this as a non-conformity in a scheme assessment is wrong because it does not breach any regulations, which is the question the OP was asking.

Fundamentally I agree, it's not good practice to be doing it, but that doesn't alter the fact that it's not a breach of the regs.

Octopus · Aug 30, 2018

BYB Definitions

Circuit. An assembly of electrical equipment supplied from the same origin and protected against over current by the same protective device(s)

314.4 Where an installation comprises of more than 1 final circuit, each final circuit shall be connected to a separate way in the distribution board ....

Neither of these state that a final circuit only has 1 cable

so............ I would say that the OP's original circuit complied 100%

Or the OP could have whipped out a short length of T&E, plus some Wago's and joined the 2 cables just before the MCB and then what

Nigel · Aug 30, 2018

I am starting to come round to this to be honest.

However all cables in any installation go back to the same origin.

Octopus · Aug 30, 2018

Wonder what the assessor would have made of a RFC, with a spur from the CU then ??

Wilko · Aug 30, 2018

essex said:
How would you record Zs etc on the cert with two finals coming from one MCB?

Wouldn't you find the largest value and use that. Same as if the circuit was made by a MF junction box a few metres away from the board (?).
Edit - apologies to others whose idea I appear to have nicked - should've read the replies before sprouting off. I will do better, I promise.

Wilko · Aug 30, 2018

I had a polite rebuttal for the Assessor's argument too, but for some reason the webby has deleted it. Perhaps it's the start of a reversal of all the double posts? So I'll stick with a pic -

[ElectriciansForums.net] Does this setup contravene any regs or is it ok?

Wilko · Aug 30, 2018

Wes1000 said:
I’ve just done a large job where I fitted a double stack board (23 ways) and by the time I’d finished we only had two spare ways left in the board. So I thought that I’d free up one more by moving the lighting circuit for the loft on to the lobby lighting circuit at the CCU so both circuits are now on the one 6A MCB. Other than that they are totally separate. They also only contain one light for the loft and two lights for the lobby (all LED’s)

To me this is no different from taking the supply from the last lobby light to the loft and actually might make it easier to find a fault if you could separate it at the board rather than mess about behind down lights.

All was good until I decided to use this job for my Stroma visit.....
I was told that in no way can I do this and I need to correct it or it will go down as a non conformity. After arguing the point for 10 minuets I gave in and put the other MCB in and moved the loft light on to its own circuit and all was peaceful again.

Who’s right here?

Well he's not right in my humble opinion

. Maybe he couldn't find anything to talk about, and some folks are not happy to be happy (won't say who ...).

westward10 · Aug 30, 2018

I like an assessor who knows his stuff.

SparkyChick · Aug 30, 2018

westward10 said:
I like an assessor who knows his stuff.

Good practice aside (although it could be argued as @Wes1000 pointed out that by having two cables at the CU allows for easier fault diagnosis - providing they are properly labelled they can be split, separating the lobby and attic), how does it contravene the regulations?

I'm not trying to be a smart a$$, if it breaches the regs, I'd like to know which ones and understand why.

Midwest · Aug 30, 2018

westward10 said:
I like an assessor who knows his stuff.

Yeah, but this one doesn't perhaps

I'm just reading the bit about (what Murdoch said) an unfused spur in App 15 (informative) RFC & Radials. It says 'An unfused spur may be connected to the original of the circuit in the distribution board'?

Pete999 · Aug 30, 2018

Midwest said:
Yeah, but this one doesn't perhaps

I'm just reading the bit about (what Murdoch said) an unfused spur in App 15 (informative) RFC & Radials. It says 'An unfused spur may be connected to the original of the circuit in the distribution board'?

SparkyChick said:
Good practice aside (although it could be argued as @Wes1000 pointed out that by having two cables at the CU allows for easier fault diagnosis - providing they are properly labelled they can be split, separating the lobby and attic), how does it contravene the regulations?

I'm not trying to be a smart a$$, if it breaches the regs, I'd like to know which ones and understand why.

Ask the STROMA guy to put his comments in writing, to enable you to send them to the IET, CERTSURE etc for confirmation and the reg number, and watch his bottom go sixpence, shilling half a crown, "note possibly not understood by the younger members of the forum"

Wes1000 · Aug 30, 2018

essex said:
He is correct and has backed it up with a Reg number.

How would you record Zs etc on the cert with two finals coming from one MCB?

He didn’t provide a reg number, that was just the only one I could really find that remotely resembles what he was blithering on about.

Like others have said, I record the highest Zs and R1+R2 but now have to alter the results with another circuit.

Thanks for all the reassurance guys and gals. It’s good to know I wasn’t wrong.

westward10 · Aug 30, 2018

SparkyChick said:
Good practice aside (although it could be argued as @Wes1000 pointed out that by having two cables at the CU allows for easier fault diagnosis - providing they are properly labelled they can be split, separating the lobby and attic), how does it contravene the regulations?

I'm not trying to be a smart a$$, if it breaches the regs, I'd like to know which ones and understand why.

The assessor may have been considering Reg 314.4.

telectrix · Aug 30, 2018

Murdoch said:
Wonder what the assessor would have made of a RFC, with a spur from the CU then ??

he'd probably have choked on the brown envelope, trying to eat the evidence.

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