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DIY Forum >> Electrical Questions >> Wiring up a distribution box
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Message started by londonman on Jun 2nd, 2017, 8:36am

Title: Wiring up a distribution box
Post by londonman on Jun 2nd, 2017, 8:36am

Lighting circuits ...

can you have multiple circuits going into one MCB ?  Retrofitting wiring as part of a renovation project and my electrician is telling me that only one circuit is allowed per MCB. Currently the house is wired with maybe 6 separate lighting feeds coming from three fuses.

I can understand (and will organise) separate circuits for downstairs and upstairs lights but if there were, say, three existing circuits for downstairs lights then surely they can all be put in the same MCB?

TIA

Title: Re: Wiring up a distribution box
Post by Lectrician on Jun 2nd, 2017, 8:46pm

Nothing wrong with two or more cables in an MCB - It is no different from jointing from a joint box or other point.  Neutrals must be in the same corresponding terminal.

Some electricians get set in the old school ways, but there is nothing at all wrong with what you are suggesting.

Title: Re: Wiring up a distribution box
Post by CWatters on Jun 3rd, 2017, 10:34am

+1

It can be more convenient to have separate MCB, one per circuit, but not essential.


Title: Re: Wiring up a distribution box
Post by londonman on Jun 6th, 2017, 7:13pm

Mmm..my electrician is saying one circuit per MCB.  Think it might be one of his 'foibles'.

Title: Re: Wiring up a distribution box
Post by Lectrician on Jun 7th, 2017, 6:51am

It is one circuit per MCB, but that doesn't mean a circuit cannot have two or three cables at the MCB.  An MCB can be the joint just as much as a joint box a foot away.  Indeed, the OSG even mentions a spur from a ring can be from the origin.

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