DIY Doctor

Installing an electric shower

Postby manod1780 » Wed Sep 16, 2009 10:31 am


i would like to replace the Heatrae Stradia shower that i have with a new Mira shower as the old one is pretty pathetic.

i was looking to install an 8.5kw shower, the old shower runs on a 30 amp fuse, can i install a 8.5kw using the same 30amp or will i have to replace the amp. looking at the maths 8500/230 = 39.9amp can a 30amp cope with that? Not sure what KW the old shower runs at can find it.

Thanks in advance
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Simply Build It

Postby kbrownie » Thu Sep 17, 2009 12:03 pm

Looks Llke you may need higher protective device(fuse) this could also mean your cable size is not a safe size to carry new higher current and if so needs to be updated.
So then new circuit will require RCD/RCBO protection and becomes notifiabe work. Under part p of building regulations which is law.(projects page part p)
So I suggest you call a registered domestic installer who can self cert his own work. It will save you money in the long run as a fee of 130GPB would be charge by Building Controls and you would still need to install it and buy materials.
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Postby sparx » Thu Sep 17, 2009 4:49 pm

hi, you have answered your own question, no a 30A fuse/mcb won't run at 40A for more than a very short time, it needs a 40A rating but it can't just be changed as wiring may not be safe at 40A, isolator switch may be only 30A rated cable size, route/length all need to be assessed by qualified leckie,
regards SPARX
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Postby manod1780 » Fri Sep 18, 2009 7:56 am

Thanks for the advise,

They guy i have doing the work for me said it would be ok, however i think i am going to call someone else after the advise given.

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