More than 1 circuit on mcb

[Wardy83]

Hi, recently carried out an eicr at a rented property. There were 5x 1mm in a 6amp mcb for lighting.. my question is what code should I be looking at for this??
I am sure I have heard someone mention or read somewhere about overpopulating an mcb should be a code 2... but then i have also heard it’s all counted as 1x circuit so all the lights to the property are on 1x circuit.. which would be a code 3 recommendation they should be split.. advice would be welcomed.

cheers

 

[DPG]

I suppose it depends if the manufacturer states the physical capacity of the MCB terminal in terms of number of conductors.

 

[brianmoooore]

I suppose it depends if the manufacturer states the physical capacity of the MCB terminal in terms of number of conductors.

They'll state the max. capacity in mm2, not the number of cables. It's unlikely that five lighting cables will reach that limit, even if the ends are doubled over.

 

[westward10]

They'll state the max. capacity in mm2, not the number of cables. It's unlikely that five lighting cables will reach that limit, even if the ends are doubled over.

Conductors not cables.

 

[Pete999]

Hi, recently carried out an eicr at a rented property. There were 5x 1mm in a 6amp mcb for lighting.. my question is what code should I be looking at for this??
I am sure I have heard someone mention or read somewhere about overpopulating an mcb should be a code 2... but then i have also heard it’s all counted as 1x circuit so all the lights to the property are on 1x circuit.. which would be a code 3 recommendation they should be split.. advice would be welcomed.

cheers

An MCB supplies a circuit, so anything connected to it is deemed a circuit regardless of how many wires there are, not an ideal situation, but seen it loads of times.

 

[littlespark]

5 conductors physically into an mcb I can see... the corresponding neutrals into one hole of the neutral bar? Don’t think so.
So the neutrals won’t match the circuit number.

So if this one circuit was one cable from the CU to a nearby joint box, which then split 5 ways.... is it 1 or 5 circuits?

 

[Pete999]

5 conductors physically into an mcb I can see... the corresponding neutrals into one hole of the neutral bar? Don’t think so.
So the neutrals won’t match the circuit number.

So if this one circuit was one cable from the CU to a nearby joint box, which then split 5 ways.... is it 1 or 5 circuits?

1 one only

 

[suffolkspark]

C3 for me if they're all in there snug, nothing really electrically wrong imo, just a bit rough, and theres often 1 conductor that isnt grasped as well as the rest, I've never come accross more than 3 myself

 

[telectrix]

"Final circuit".

is that you final answer? do you want a 50/50?

 

[telectrix]

Conductors not cables.

youse bin taking them pedantic pills again?

 

[telectrix]

it's a C3 in my book. division of circuits to minimise danger and inconvenience. improvemrnt recommended. and that's my final answer

 

[telectrix]

Conductors not cables.

but if he'd said "lighting conductors" that could be mis-read as "lightning conductors" which is a whole new barrel of fish, till the pikeys see the £££££s value in scrap of 50 yards of 1" x 1/8"copper, then it's gone in 60 seconds. weighed in before Plod even squeezes his 18 stones from inside his climate controlled warm BMW 5..to plant his flat feet on terra firma.

 

[Pretty Mouth]

It is one final circuit. All line conductors are connected downstream of the final protective device, the operation of which isolates them all.

 

[littlespark]

1 one only

Of course it is.

 

[telectrix]

agree. 1 final circuit with 5 branches ( as in radials, RFCs would be spurs). might be compliant but bad practice as in division of circuits blah, blah. and just to add insult to injury, those cables (conductors, westie) are probably red and black, so that's got to be a C2 as nobody these days recognises red as a danger colour, all cables are grey in the dark. like cats.

edit: just bin pokin about in the garden. ladybirds are morphing into brown and grey . they must have been reading up on the regs from 2006.

 

[7029 dave]

It is one final circuit. All line conductors are connected downstream of the final protective device, the operation of which isolates them all.

Not in a scam, just created a new circuit lets jam another in the existing one. lol