by ericmark »
Mon Feb 28, 2011 2:58 am
As you say no different to fitting a shower as far as cable and load goes so no real problem fitting one as long as the incoming supply is big enough.
The incoming supply is nearly always through a 100A fuse holder but as the user you have no idea normally what size fuse is inside the fuse holder. Anywhere between 60A and 100A.
This may put some electricians off as all too easy you can end up with more than the supply fuse can handle and be blamed for the loss of power.
Other factors are the type and size of consumer unit. Today any cable buried has to be either one of the specials allowed or protected by a RCD. If the consumer unit will not take a RCD the cost to do the job could raise.
When installing units using high power the first step is to test the existing supply. The earth loop impedance, the existing demand, the size of supply will all be taken into consideration. It may be electricians in your area know the houses in that area don't have the supply you will need.
But it is not really any good asking on a forum. It is your local electricians you need to ask.
Part P has become a problem. Only electricians who pay a large annual fee can work on domestic premises and do all the work. Before 2004 electricians who were mainly commercial would do the odd domestic job but the government rules mean to do the odd job will cost over £100 to register that single job with the LABC. Unless the job is large for example complete re-wire then it is not worth doing the job if one is a commercial electrician. The only exception is where it is part of a bigger job for example an extension where the same building control fee can cover both building and electric work.
With those doing domestic electrics their scheme providers do place some heavy restrictions on them. Although the LABC can allow you to do work which does not comply with BS7671 if it is still safe. The domestic electrician has to follow it by the letter. Also he can only sign for work he has done and if some of the work has been done by some one else this can also cause problems.
