RCD/MCB ubit

[stephen123]

I have just had a conservatory built and the electrical sub-contractor to the conservatory company has said that we need a new consumer unit fitted as the new legislation says that new ground floor sockets have to be connected to a rcd/mcb unit. The company concerned have given us the following quotation, "Replace the exsiting consumer unit with a new RCD/MCB unit and meter tails to provide RCD protection to 13 amp socket outlets.



Carry out all necessary supplementary bonding to comply with regulations.



Test all existing circuits and connect to new consumer unit.



Provide completion certificate for the above works.



Cost �403.56 plus VAT."



Two questions; is this a reasonable price?



Can a RCD/MCB unit be fitted to the circuit serving the new sockets only?

[BillyNoMates]

Doesn't sound too bad - depends on what part of the country.

Yes, the new sockets could very easily be put on a new, separate circuit protected by an MCB/RCD.

Really comes down to how old and in what condition the existing wiring/fusebox is in.

[buildersmate]

About one very long days work. Materials would be about �70. Sounds reasonable.

[stanleyman]

I'm intrigued about this new legislation requiring new ground floor sockets to be connected through an an rcd/mcb unit, I seriously doubt it. Anyone have info?

An MCB is more convenient and sensitive but a fuse can be better with surge currents. An RCD is only required if the powerpoint can be used outside and this may apply in a conservatory. Some outlets such as a fridge/freezer, computer etc. and lighting are better off without an RCD.

You could either fit an outside or inside RCD socket to comply or an RCD in the supply tails. Having said that, it is advisable to fit an RCD on all circuits supplying portable appliances for better protection and fitting MCB's where it is convenient or necessary to reduce a short circuit voltage but this should be for the right reasons not made up ones to gain business.

If the quote is for additional powerpoints as well as a new consumer unit and supplimentary bonding then it would be reasonable but not otherwise. You would do well to get two other quotes and opinions.

[stephen123]

Thanks for your replies.

Stanleyman,

I was told that the rules apply because there is the likelyhood of ground floor sockets being used for outside electrical equipment. The price does not include the new sockets.

[BillyNoMates]

That's the explanation I would have given too - potential of any ground floor power socket being used for a lawn mover etc etc.

[stanleyman]

I was just being pedantic because I don't agree with this broad interpretation, not all sockets are likely to be used outside. If you were to fit some outside independant RCD sockets or fit them on outlets near windows and doors likely to be used outside then you would be fully compliant with no further work required as per your question. MCB's have nothing to do with this and you don't have to change a perfectly good fused consumer unit unless you really want to upgrade the whole thing.

[BillyNoMates]

I totally agree with you stanleyman - nanny state strikes again !

[Toureman]

On this subject...

Why can anyone buy waterproof sockets from B&Qs etc. and fit them anywhere they want outside with no mention about also using an RCD?