electrical question

helpimcrap

helpimcrap

helpimcrap

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Leicestershire
i am not happy i've had to resort to the internet for this question but i'll explain:-
Basically I have 6mm twin earth cable coming from fuse box and it's going to an isolation ceiling switch in the ceiling. then it's going back into the ceiling and coming down a plastered and tiled wall to power an 8.5kw power shower.

So we have:-

Guse box-> 6mm twin earth-> en suite ceiling with an isolation switch -> 6mm twin earth behind plaster and tiles -> 8.5kw shower.

Basically the only isolation switches i can find are 45amps and i've had a look at shower instructions for an 8.5kw shower and that says 30amp if the wire is in plaster. according to that then i need a 30amp isolation switch otherwise wire will burn out.

Is that true?

i am NOT going to take this advice as given so feel free to help and offer comments but i am stuck and need to explore all routes as i am looking to fit the shower tomorrow but need to buy an isolation switch and no one can offer help! :mad::rolleyes:
 
any raise on nothing? lol

says 30ma RCD (what is one!?) and a 45amp isolating switch double pole. so i guesss thats the osolating switch question answered?

fuse box fuse (if thats the one) is 40amp. i say i think coz my dad did it all before he died and i've had to pick up where he left off.
 
Does not matter how large the rating is on the isolator (as long as its not under sized). It could be a 1000 amp its there to isolate the supply not protect it.
You do not need to put the circuit on a RCD it would just be a departure code 4 does not comply with the 17th edition regs. If it was a new install (a part P certified person installing a new circuit from your fuse board to the shower) then yes RCD protection has to be implemented (bathroom is a special location). Also all pipework has to be a the same earth potential as all the electric circuits in that room.
Another thing if this is a new circuit being installed it should be tested and building control must be informed.
Any more questions please ask.
I should say 'you should be using a electrician really'.

RCD: residual current device a device that trips out under earth fault condition
 
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they way i see it is

fuse box >6mm/10mm T+E>45amp isolation switch>shower!

depending on the load of the shower ofc, 8.5kw = 36amps
8500/230 =36
 
as far as I am aware, the RCD is the bit on the fuse board, its the thing that cuts the power if there is a fault to stop you getting electrocuted.

I think it's different to a standard fuse board fuse, so may need to check that it is an RCD type.

The isolating switch is the switch in the bathroom (often pull cord type) like you thought.
 
yea just re read that and its normal to have a 45amp iso switch for a shower! its prob a pull switch and will take a maximum load of 45amps, you shower wont exceed 36 so you fine!
 
ah cool, thanks for the insights chaps. just need to get my head around this RCd thingy now. the fuse box should have one you say? what exactly does one look like?!? :confused::o it's a fuse board that's been installed in the last 15 years.
 
I would imagine something like this

r2ryow.jpg


should be labelled up for which one is the shower, the rating should be printed on it too.

Wouldn't go playing around with it though, best to get someone who knows what they are doing to check it over for you.

Better safe than sorry.
 
Your shower might not necessarily have a RCD dedicated to it. You may well find that your consumer unit (fuse box) is protected by a RCD, which in turn protects anything connected to it (normally via a busbar, which is a copper connector normally encased in plastic). So the RCD will protect not just the shower but possibly the power circuits etc etc. RCD's will have a "Test" button on them as the photo above shows.

i.e. RCD>MCB>6mm/10mm T+E>45amp isolation switch>shower

Do you have a RCD in your fuse box? Do you have a MCB just for the shower?
 
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