Change Cooker Supply to Electric Shower? Ask questions and find answers to many subjects relating to electrics and electrical work

[asifkhokhar]

Hi everyone!

I am really sorry-I have not read up about this at all, but we recently opted for a new loft conversion and thought we would get a new small bathroom upstairs too. However, we were kinda haggled into getting an electric shower by our builder, who has put a 10mm lead to the power supply from upstairs, but now he wants us to pay for the electrician's work.

However, there are only 4 switches (RCD? You can see I know nothing!!!) on the fuse box and they are as follows:

Cooker 32A
Plugs 32A
Downstairs lights 6A
Upstairs 6A

No spare!!!
BUT...we have a gas cooker, and don't need the cooker electrics!
So, is it possible for electricians to change the cooker supply and connect the shower? The builder-given electrician says it isn't and seems adamant on getting us a new board and billing us half a grand in the process!

Any suggestions!
Thanks-sorry again for my complete ignorance!!!

[kuzz]

A new fuse board sounds like good advice to me. And if that price includes the board, wiring the shower, upgrading the bonds and testing then it's very reasonable.

[ericmark]

Until July 1st you could add a sub board which may use the cooker supply to feed the shower through a RCD assuming you need no power to cooker. But most gas cookers still need power. He may be able to use a Service connector block to add a consumer unit for the shower which would then retain the original four ways and add an extra way. See for example Screwfix 11497 and 69659 under £50 for parts in theory. But we have not seen your set-up and if for example the earth bonding is not up to scratch then that would also need doing. The meter tails may also be under rated, so another little bit. It is unlikely a four way unit will have any earth leakage protection and we don’t know what type of supply you have if it is a TT supply he could hardly leave it without adding earth leakage and even with a TN-C-S supply it could be considered that since he was last person to work on the system is should have earth leakage on sockets too. Very quickly you reach a point where to change the consumer unit is cheaper than trying to up-grade what you have.
Once one decides to change a consumer unit then it would make sense to comply with the latest regulations. At the moment you can get away using the 2001 regulations but by July the 2008 regulations must be used. This means multi-RCD’s which bump up the price looking a screwfix which is reasonable we get:-
Dual RCD Split Load Unit at £111.95 and this does not include the feed cables £24.08 for 5 meters and earth cables £33.19 for 25 meters 16mm² I know it will not require a full roll but to allow £40 for cable is not unreasonable plus the registration fees with building control as the builder as installed the cable to the shower he can’t use the self cert system. This means he’s doing the job for £300 i.e. about 2 days work. I have fitted a consumer unit in a day which leaves him with good profit but also I have still been correcting faults 2 days later where the fitting of an RCD has highlighted problems we had never considered.
My father paid an extra £60 to have new consumer unit fitted with his shower, but once fitted the electrician ran off into the hills of North Wales never to be seen again. Leaving me to sort it all out. So getting it done on the cheap is not always a good idea.
So long as the £500 covers all work to bring the system up to the latest 17th Edition (BS 7671:2008) regulations complete with a completion certificate from building controls it’s not a bad deal. But no point going to old 16th Edition (BS 7671:2001) now as it will then all have to be done again just to add one socket after 1st July 2008.
To upgrade to 17th makes sense as after the 1st July unless you have up graded it could cost £500 just to add one socket.
The new regulations do make electrical systems much safer and less likely to trip out than with the old regulations so not all bad.