new consumer unit

hey all, just after a bit of advice really, i have bought a new consumer unit and would like to know which circuits my rcd should protect, i have 8 circuits - upstairs ring, downstairs ring, kitchen ring, upstairs lights, downstairs lights, cooker, garage, and immersion/shower pump. i know garage and cooker is a must, but was just after your ideas on the 3 rings and immersion/shower pump.
Also my volex unit has 3 6amp mcb's, 2 16's, 4 32's and a 40, i know i'll use 2 6's for both lighting circuits and the 40 for my cooker but any advice on what the other circuits should be protected by.
Any advice at all would be greatly appreciated apart from anyone pointing out part p - as soon as its done it will all be tested and certificated
Cheers guys in advance

I'm sorry to pee on your matches but by the nature of your question are you sure you should be tackling this job yourself.

I'll ask you a question are you aware of BS7671?

davedasave said:

hey all, just after a bit of advice really, i have bought a new consumer unit and would like to know which circuits my rcd should protect, i have 8 circuits - upstairs ring, downstairs ring, kitchen ring, upstairs lights, downstairs lights, cooker, garage, and immersion/shower pump.

I know garage and cooker is a must, but was just after your ideas on the 3 rings and immersion/shower pump.

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Do you know what your earthing arrangement is? If it is TT then everything is RCD protected but those labeled below as RCD are protected by the 30mA RCD and those labelled non-RCD are protected by the 100mA TD RCD.

upstairs ring - RCD - 32A - 2.5mm² twin & earth
downstairs ring - RCD - 32A - 2.5mm² twin & earth
kitchen ring - RCD - 32A - 2.5mm² twin & earth
upstairs lights - non-RCD - 6A - 1.5mm² twin & earth
downstairs lights - non-RCD - 6A - 1.5mm² twin & earth
immersion/shower pump. - non-RCD - 16A - 2.5mm² twin & earth

Is the garage attached? If so assuming it is a ring circuit also: RCD protected - 32A - 2.5mm² twin & earth. If not how far is it from the CU?
What is the rating of the cooker?

Cookers have high amounts of earth leakage under normal conditions which could cause nuisance tripping so fit a cooker switch without a socket and put it on the non-RCD side.

davedasave said:

Also my volex unit has 3 6amp mcb's, 2 16's, 4 32's and a 40, i know i'll use 2 6's for both lighting circuits and the 40 for my cooker but any advice on what the other circuits should be protected by.

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Are you rewiring or just replacing the CU? If you are rewiring consider running a 16A 2.5mm² t&e radial to the kitchen for the fridge/freezer and do not RCD protect this. See above for MCB ratings and cable sizes that should be use.

davedasave said:

Any advice at all would be greatly appreciated apart from anyone pointing out part p - as soon as its done it will all be tested and certificated

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I'm going to point out part P anyway. Have you informed them? If not you must do so BEFORE starting the work and get it inspected during first fix and then inspected and tested after completion.

I also feel it necessary to point out that by you asking these basic questions you have given me serious doubts as to whether you are competant enough to carry this out safely. Are you aware of the safe zones regarding cable routing? Are you aware of ALL current regulations (BS7671)? Main/supplementary bonding? How do you intend on isolating the tails before you can change the CU?

Davy

The name says it all...


davedasave


You may get annoyed reading the replies posted here, but it is imperative to understand that there is a certain level of knowledge & compentence that must be achieved BEFORE you pick up a tool in anger, if you are contemplating something as major as this.

I don't mean major as in difficult. It isn't difficult, but you must understand what you are doing and WHY.

There are some test procedures which ideally should be carried out before you swap the board out, and these need equipment not readily available.

To be a legal job, you need to contact your BCO before you commence work.

We don't mind putting folk on the right track with electrical jobs, but, equally, i we feel they're biting off more than they can chew, we let them know.

How much knowledge have you got in this area?

davedasave said:

... as soon as its done it will all be tested and certificated...

Click to expand...

Yet another poster with an imaginary electrician on tap.

dingbat said:

davedasave said:

... as soon as its done it will all be tested and certificated...

Click to expand...

Yet another poster with an imaginary electrician on tap.

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I just wonder how the certificate issued can be valid if the "electrician" does not see the installation of the cables to ensure no damage occured to them.

The electrician could just sign for inspect and test and the poster could sign for both design and construction. Of course the electrician could not put such a job through his scheme mebership and the local BC would have to be involved