Does this setup contravene any regs or is it ok?

[elsparko]

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 -

View attachment 43990

not allowed pics mate, westward will have a wobbly

 

[elsparko]

tell the assessor to come back round and rub his nose on the mcb till he understands hes wrong

 

[Nigel]

This is one of those rare times that BS7671 contradicts it’s self.
On the one hand we have a Regulation telling us each circuit must be connected to a separate way at a DB.
Then on the other hand we have a definition telling us that however many circuits we connect to a separate way, they all become one circuit by virtue of being fed from the same origin and being protected by the same OCPD.

I think the intent of 314.4 is to not link two circuits together downstream so that say the ground floor lighting is not linked to the upstairs lighting when protected by seperate OCPDs. This could cause an issue when isolating safely. It would also cover borrowed neutrals.

I think the interpretation that it means each final circuit must have an independant OCPD is a red herring.

 

[Deleted member 26818]

The Reg states final circuit which also has a definition.

Don’t think the definition of a final circuit would have any bearing on the matter?

 

[Nigel]

This is one of those rare times that BS7671 contradicts it’s self.
On the one hand we have a Regulation telling us each circuit must be connected to a separate way at a DB.
Then on the other hand we have a definition telling us that however many circuits we connect to a separate way, they all become one circuit by virtue of being fed from the same origin and being protected by the same OCPD.

I think the intent of 314.4 is to not link two circuits together downstream so that say the ground floor lighting is not linked to the upstairs lighting when protected by seperate OCPDs. This could cause an issue when isolating safely. It would also cover borrowed neutrals.

I think the interpretation that it means each final circuit must have an independant OCPD is a red herring.

 

[Deleted member 26818]

I think the intent of 314.4 is to not link two circuits together downstream so that say the ground floor lighting is not linked to the upstairs lighting when protected by seperate OCPDs. This could cause an issue when isolating safely. It would also cover borrowed neutrals.

I think the interpretation that it means each final circuit must have an independant OCPD is a red herring.

Interpretation?
The definition of a circuit states: “protected against overcurrent by the same device(s)”.

 

[Nigel]

Interpretation?
The definition of a circuit states: “protected against overcurrent by the same device(s)”.

I am unsure of the relevance of this post to mine.

 

[Deleted member 26818]

I’m not sure what it is you mean when you state this:
“I think the interpretation that it means each final circuit must have an independant OCPD is a red herring.”

 

[Nigel]

I’m not sure what it is you mean when you state this:
“I think the interpretation that it means each final circuit must have an independant OCPD is a red herring.”

Some people’s arguement is that to connect two final circuits to the same MCB is a contravention to Reg 314.4.

I think that is not the intention of that reg.

 

[The Ghost]

I imagine he would have conniptions if he (assessor) saw some of the multi light circuits and RFC with comms sockets connected at MCB that I regularly see then. I can't see why the loft light was not put up on the upstairs lighting in the first place. Someone wasn't thinking, one light on a 6a MCB could be argued to be not taking account of the sections referred to in 314.x.x i.e. OCPD. I can't see any of the stipulations from i-iv have been breached though. But it is very on the "raggedy edge" arguing the point. So the assessor could be asked what he makes of OCPD for one LED light (4-7w) 7/230 =0.03 A, does that make sense?

 

[westward10]

One light or ten lights, makes no difference. From what the OP has later stated though I don't believe the assessor was actually referencing the Reg in question.

 

[Deleted member 26818]

Some people’s arguement is that to connect two final circuits to the same MCB is a contravention to Reg 314.4.

I think that is not the intention of that reg.

Well to connect two final circuits to a single OCPD would contravene Reg 314.4.
However it becomes a contradiction in terms, because by doing so the two circuits become one circuit as per the definition of a circuit.

 

[Wilko]

I remember (and adhere) to your wise advice of a year or two ago Westy, say as little as possible to Mr A.
Less said, less to repair .

 

[Nigel]

Well to connect two final circuits to a single OCPD would contravene Reg 314.4.
However it becomes a contradiction in terms, because by doing so the two circuits become one circuit as per the definition of a circuit.

I don’t think you understand my point.

 

[westward10]

But the Reg quotes final circuit and not circuit so there must be difference as both are listed in the Definitions.