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Fuse Boxes For Showers (Please could you advise me)

Postby Petrena » Sat Sep 13, 2008 4:25 am

Fuse Boxes For Showers

My flat was totally rewired about 25yrs ago and I have a separate MEM consumer unit which holds a 30amp HRC Cartridge Fuse for my shower leading into my main fuse box which and electrician did when I first got my first shower. All this was done by a qualified electrician

I have recently had to replace my old shower which was a Triton
T80 and that ran on a 30 amp fuse, which was attached to an older 1 way MEM Consumer Unit. Now as far as the shower was concerned that was easy to swap them in the bathroom. Now after asking Triton what shower to replace my old one with, they advised me that I had to get a 45 amp fuse for the Triton T80si to work.

Now all the wiring is in place from the last shower, nothing has been disturbed. However when I went to put the 45 amp fuse in, it wouldn't fit, because the holder wasn't big enough. However I have come across a problem, that when I got the new holder, the pins on the new holder face length ways, instead of straight across. Now I wondering if there is a holder that can hold my 45amp fuse, with pins going across between the fuse or do I have to get a new consumer unit.

Please can someone advise me, because I feel the electrician I saw today was talking way over my head and his list was endless in what he wanted to do which would of cost me in access of £2000 which I simply don't have and to be honest the main switch box in good condition so I don't really think it needs replacing, and I have been trying to look through the websites for advice as to what I really need, but I just don't seem to be able to find the component needed.

I'm sorry to be vague, however I have tried to look up what I am saying to you, so that you can understand. What I am trying to find out is what I do actually need so that I can ask a local electrician to fit the right component without it costing me a fortune, which I don't have.

Thank you for your patience and understanding.

Take care
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Postby ericmark » Sat Sep 13, 2008 1:52 pm

I am sorry but all registered electricians have to follow a rule book “BS7671:2008” this book allows a like for like swap but as soon as you up-grade one bit you have to up-grade all.
The fuse box is designed to stop one fitting a fuse that is too big. Yours has done its job as it is not just the fuse that would need changing but also the cable will need to be checked as to what route and in view of route what the maximum fuse size that can be used.
From what you have said I would expect you will need a new consumer unit although this may be a mini type just for the shower which will contain a trip that has earth leakage as well as overload within it.
Often these are fed by what is called a Henley block which splits the supply. There is some debate going on as to single switching and some electricians will not fit these units as they consider there should be a single switch but there are normally some methods of getting around this.
The rules are tying electricians hands in many ways, unless one is registered to an organisation to allow one to sign building control completion certificates much of the work would require massive fees to be paid to local council and the organisation dictates how they are to operate and there is a directive as to what they must group together as single job. And they are instructed to refuse work if the customer will not pay for a minimum amount of work to comply to regulations.
The rouge electrician has no such limitations of course and the Part P regulations have created a safe market for the rouge electricians as where the house holder accepts he/she is breaking the law by not declaring the work if he does sub-standard work he is unlikely to be reported as the house holder knows they will also be in trouble if they report them.
Having said that £2000 seems rather high.
If I assume a whole day I would consider £200 labour but lets double that and say £400 plus new consumer unit another £400 and new cable to shower £100 should cover that so £2000 seems double what I would have expected from what you have said.
There is of course different costs in different areas.
So what you really need either get an equivalent shower to old one i.e. same wattage that is then it would be considered like for like change.
Or/and an extra box to supply shower screwfix show them as costing £40 see 90026 plus connector block 2 x £3.80 11479 and cable at 2 x £12 29235 + 82604 so approx £70 for materials min plus labour.
If you fuse box is faulty then we are looking more money £137 80819 for a 8 way board and one does wonder if it is worth not having the extra protection with RCD on all circuits when only £67 more than botch with single RCD and MCB in it’s own board.
Can you explain more what he wanted to do?

Postby nitro23456 » Sat Sep 13, 2008 2:20 pm

......or look for the exact same shower etc on ebay.
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Postby TOPSPARK » Mon Sep 15, 2008 7:19 pm

First of all you have not said the rating of shower. If it is a 8.5kw or a 9.5kw output.If it is the latter then i am afraid you would need to upgrade the cable to 10mm squared twin and earth cable and by the sounds of what you are saying you will need to upgrade your fuse box to a new one that complys with the 17th edition wiring regulations.But another way would be to get a shower consumer unit and the 100 amp connectors to split the supply andget some 10mm squared cable then have an electrician come and do the work that is needed but with your description being not so clear can only give you these options
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