Regulation clarification

[Guitarist]

A single or double socket taken off an RFC MCB at the CU is perfectly acceptable in 2.5mm, as it is no different than a spur from any other point in the Ring. Only 1 allowed, mind.

 

[telectrix]

agree with murdoch. code C3 at worst.

 

[brman]

I haven't got the reports in front of me but from memory they are 3x2.5's in a 16 breaker so no danger

you still don't really say what the 3 "circuits" are but if all 3 are radials then I can't see any problem at all. No one would complain if they were joined at a junction box 2 inches from the CU so why not in the CU itself?
Even if it is a ring and a radial then I don't see the problem with a 16A breaker, everything is still protected properly.

As everyone else had said, by definition they are a single circuit as they are on the same breaker. I'd be asking the nic to explain what exactly is dangerous about it!

 

[brman]

A single or double socket taken off an RFC MCB at the CU is perfectly acceptable in 2.5mm, as it is no different than a spur from any other point in the Ring. Only 1 allowed, mind.

Your post might have overlapped Steve's where he says it is on a 16A breaker. On that bases I'd be happy with a spur being a radial with multiple outlets.

 

[Jimmy Boy]

I will need to have a chat with them I like the analogy of the circuit being cut in two inches from the board good that is, I don't think nikky said it was dangerous just a C2, in 314.4 it states..

Where an installation comprises more than one final circuit, each final circuit shall be connected to a separate way in the distribution board.The wiring of each final circuit shall be electrically separate from that of every other final circuit, so as to prevent indirect energizing of a final circuit intended to be isolated.

So if you decide to run another final circuit, ie a run of Radial sockets or lights how does dipping into a used way comply with this reg ? I'm not saying your necessarily wrong but it seems clear cut ?

 

[ackbarthestar]

I am struggling with this thread........
Why am I struggling?

Well, if you are a member of an authorizing body, such as the NICEIC then you are bound by their regulations to follow their rules.
So there is not much you can do. If your assessor tells you that you cannot use SWA as an earthing conductor, or you have to use a taped up crimped ring connection on MPBC, or having 3 * 2.5mm2 conductors in a 32A MCB where two of them form a RFC is potentially dangerous, then you are obliged to follow their rules. A departure from their rules will initiate disciplinary procedures.

I'm not a member of this 'bend down and kiss my ring, on my finger' club so their rules don't apply to me or to anyone else who is not a member.

Just a note to think about:

What do you think might happen to a socket outlet supplied via 2.5mm2 cable protected by a B32A MCB ?

 

[spark 68]

So if you decide to run another final circuit, ie a run of Radial sockets or lights how does dipping into a used way comply with this reg ? I'm not saying your necessarily wrong but it seems clear cut ?

I think you are missing a point here, it is not another final circuit, it becomes a part of the same final circuit, see Johnboys post about definitions in part 2.

 

[brman]

I will need to have a chat with them I like the analogy of the circuit being cut in two inches from the board good that is, I don't think nikky said it was dangerous just a C2, in 314.4 it states..

Where an installation comprises more than one final circuit, each final circuit shall be connected to a separate way in the distribution board.The wiring of each final circuit shall be electrically separate from that of every other final circuit, so as to prevent indirect energizing of a final circuit intended to be isolated.

So if you decide to run another final circuit, ie a run of Radial sockets or lights how does dipping into a used way comply with this reg ? I'm not saying your necessarily wrong but it seems clear cut ?

The question there is is it designed as a single circuit? If you add another radial and only look at the design currents etc for that radial then sure, it should be on a seperate breaker as that is what you have designed for. If on the other hand you calculate that adding the new sockets as an addition to the old circuit is acceptable (ie you take into account the old circuit in your design) then I see no problem having them on the same breaker.
That is the way I see it anyway.....

 

[Octopus]

I think you are missing a point here, it is not another final circuit, it becomes a part of the same final circuit, see Johnboys post about definitions in part 2.

Yes, BUT, I think the OP is referring to an old CU where there are more circuits than fuses. In such cases, IMHO, as long as the fuses and cables and circuits are all within design specs then its OK.

Suggesting a C2 and quoting for a 2nd or new CU in such cases, I think, is not in the best interests of the industry and as such is a great example of where people have good cause to think that "we" find unnecessary work. If its 3 x 2.5 radials in a BS3036 board, and its been like that for some time is it really a problem? I think not, and if the Nikki think it is well, I still think they are wrong and more to the point THEY DOI NOT make the rules.

However if the customer has fuses regularly blowing due to excessive load across 3 circuits it still only a C3 IMHO

 

[brman]

I am struggling with this thread........
Why am I struggling?

Well, if you are a member of an authorizing body, such as the NICEIC then you are bound by their regulations to follow their rules.
So there is not much you can do. If your assessor tells you that you cannot use SWA as an earthing conductor, or you have to use a taped up crimped ring connection on MPBC, or having 3 * 2.5mm2 conductors in a 32A MCB where two of them form a RFC is potentially dangerous, then you are obliged to follow their rules. A departure from their rules will initiate disciplinary procedures.

I'm not a member of this 'bend down and kiss my ring, on my finger' club so their rules don't apply to me or to anyone else who is not a member.

Just a note to think about:

What do you think might happen to a socket outlet supplied via 2.5mm2 cable protected by a B32A MCB ?

I've always found this a bit odd - the BGB says this is perfectly acceptable as long as it is coming from a ring and there is only one 2 gang socket on it. But put a single socket on 2.5mm2 on its own 32A MCB and you will get strung up for it

 

[spark 68]

Yes, BUT, I think the OP is referring to an old CU where there are more circuits than fuses

I could understand your point if say everything was on one fuse, ie. for example, mixed use sockets and lights on an unsuitable OCPD, but as you can use the fuse/MCB as a JB, say for example on an older install both U/S and D/S lights (or sockets for that matter) on one suitable OCPD, this is one Final circuit by the definitions given in Part 2 (Johnboys post) no matter how many conductors are terminated at the OCPD.

Iam not saying that this is best practice, or that you would design a new install this way, but as long as it is correct in all other aspects then Iam not sure how it becomes a code two

 

[Jimmy Boy]

Q & A of the Day - Can I wire two radial circuits from the same breaker? - Voltimum UK - Electrical Installation Products and Contracting

:6:

 

[spark 68]

If I can put it another way.

Say we did something really daft (for arguments sake), say we had 4 downstairs lighting points, and each had it's own supply cable, and we terminated all 4 conductors on a 6A fuse, is this any different than using the loop in loop out or 'Spider JB' method electrically speaking ?, and would it warrant a C2 ?

 

[Mr.Ian]

If I can put it another way.

Say we did something really daft (for arguments sake), say we had 4 downstairs lighting points, and each had it's own supply cable, and we terminated all 4 conductors on a 6A fuse, is this any different than using the loop in loop out or 'Spider JB' method electrically speaking ?, and would it warrant a C2 ?

Far safer in reality as there then isn't a single 1.5mm carrying the full load of everything after it !!!!

 

[Jimmy Boy]

I think you are all correct it's a 'does not comply with 7671'
I have emailed the nikky spark (who I get on with really well) and see what he says