Consumer unit preference

17 Mar 2005
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United Kingdom
I was quoting a job not related to this question (im not a sparks)
And was asked about a consumer unit (replacing)
What consumer unit would be the best option not the make but
Standard unit with main switch
Standard unit with rcd
Slit load with main switch lights etc and rcd sockets/cooker etc
Split load with time delay rcd as main switch and rcd for sockets/cooker
I prefer the split load with main switch and rcd as at least if it trips in the night all the lights don’t go out
Is it now a regulation to have everything rcd protected ?
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Its a regulation to have buried non-armour cables <50mm deep RCD protected.

Its a regulation to have all electrical equipment in a bathroom RCD protected.

Its a regulation to have all socket outlets RCD protected.

So yes, in a standard domestic premises, unless special care has been taken to negate the factors above (mainly earthed metal conduit or SWA for buried cables), then all circuits must be RCD protected.

There are a number of ways to afford this.
The best and most expensive is an RCBO for every circuit.
Next is a split load dual RCD+mainswitch.
Then you have main RCD units - but these arent recommended due to an RCD's characteristics - they like to nuisance trip, and its a PITA when your freezer defrosts before the electrician arrives. Its also not in the spirit of the regs to wang everything on one RCD.

Of course, every installation is different. So every job would be specc'd differently.

Your post doesnt inspire me with confidence in your ability to do such work as this. Please dont.
Thanks Steve for your reply I did say that the job I was quoting was not related to this question as im not a sparks so I will not be doing this work I was just asked the question myself and I said I prefer the split load unit with main switch and rcd to protect the sockets etc so I was then curious if my thinking was correct.
Also with a split load unit what would/should be on the main switch side and what on the rcd side ? (Just another thought I had as I have had some nuisance tripping myself
Many thanks
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it's horses for courses.. each sparky will have his or her own idea of what goes on what and what board they prefer..

the 3 way split boards are popular so I've heard, giving you a main switch and a few non-rcd ( rcbo capable ) ways for things like smoke detectors and fridge maybe, and then 2 rcd sides with 4-8 ways on each for splitting up the rest of the house..

for example one RCD side would have the downstairs lights, upstairs sockets, kitchen sockets on it, the other would have the upstairs lights, downstairs sockets, cooker etc.
that way if the rcd for the upstairs lights went, your bedside table lamp would still work and so on..

there's the more costly option of the older split board where half are on one RCD, the other half isn't.
on these you use rcbo's on the non-RCD side to provide rcd protection where needed whilst still maintaining some kind of defence against nuisance tripping.

then there's the even more expensive option of not having a split load one at all and fitting RCBO's where needed ( which as listed above is most circuits now.. )..
this gives the greatest defence against nuisance tripping.
I didnt know the old style Crabtree MCBs fitted the new boards?

I've got loads that I though were good as useless now :rolleyes:
Aye, they are as good as identical, crabtree didn't want to change them, siemens, who make them, had other ideas.

Its since been swapped out for a new style one.

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