Electric Shower Switch Advice

anotheruser

So just been a bit scared.

Our electric shower stopped working a week or so ago.
It's turned on by means of one of those pull cord switches that turns on some electric in the bathroom. As ours didn't have any light on it, I assumed I needed a new switch.

Bought one and fitted it. The old one was 40amp, this is 50amp but it's the only one that Wickes sold. 10 amp surely isn't that different? It also only has one earth slot, but the diagram shows both sides going to the same place. The old one had two separate ones.

Anyway, the switch was set to on. I turned on the main power switch to that part of the house (it's an extension which has it's own board). Turned on the wall sockets, turned on the lights - so good so far.
Then, when I turned on the shower, there was a small pop and everything went out. So much so, the main board in the house cut out.
I'm absolutely positive I fitted the live/neutral/earth correctly as per the diagram (although I will double check).

Can anyone e explain what may have happened, why it happened, and if it's now pointing to a dodgy shower rather than the switch?

When the fuse board cut out straight away, it quite shook me up as I hate doing anything like this!

Thanks


EDIT: Turns out Wickes does do 45 amp ones here: http://www.wickes.co.uk/Wickes-45A-Shower-Control-and-Pattress/p/710419
Perhaps it blew because it had an extra 10 amps. Will have to change this tomorrow and see what happens.

Mr.Generous

Its nothing to do with the amp rating of the switch, 50amp is higher rated and therefore a better margin of safety. Both of these switches will be double pole, so both the live and neutral feeds are broken by a switch. Its possible you have wired live / neutral reversed one way or another, or if you haven't used earth sleeving the earth wire is touching either the live or neutral bare wire somewhere.
If it is wired properly (and the connections should be good and tight too) then the shower has an internal fault and needs replacing.
Because you describe the mains board shutting off straight away I'm guessing the RCD tripped rather than the individual MCB which feeds the shower. If it was the RCD which controls either all or half the entire mains board it indicates a leak to earth rather than an overloaded circuit. IE check and re check the wiring !!

anotheruser

Thanks

The earth wires were a little bare when I fixed them in so they may have been touching when I pushed the switch back in. I'll need to find a better way of covering them

Ectophile

Green and yellow stripey sleeving is the correct way of covering them. It should be available from any store that sells cables.

tacpot12

The wires from the board should be connected to the terminals marked Supply. The shower should be connected to the terminals marked Load. Red/Brown cables are the 'live' cables and should be connected to the terminals marked "L", Black/Blue cables are the neutral cables and should connected to the terminals marked "N".

Assuming the switch has a light to indicate that it is On, I would suggest that you disconnect the shower from the switch - leave it so that just the Supply cable is connected. Put electrical tape over the ends of the cable from the shower, and fit the switch back into position. Now restore power. Check that the light comes on and off when you pull the cord. If the main board trips out when you restore power or when you turn the switch on, you need to call an electrician because you or the wiring is not safe, and we would like to know which. :-)

If the light comes on and the RCD doesn't trip, you can turn the power off and connect the shower. If the RCD trips with the shower connected, you have a faulty shower.

Please work safely. Turn the power off in as many places as you can, and always check it is OFF before going near the switch.

Finally, PLEASE call an electrician out once the job is done and you know whether the shower works. These large switches are notorious for not having the terminals done up tightly enough. This causes a low resistance, leading to the terminals getting very hot which results in damage to the cable insulation.

shaun_from_Africa

tacpot12 wrote: »

Finally, PLEASE call an electrician out once the job is done and you know whether the shower works. These large switches are notorious for not having the terminals done up tightly enough. This causes a [STRIKE]low[/STRIKE] high resistance, leading to the terminals getting very hot which results in damage to the cable insulation.

Corrected for you.
Loose terminals cause sparking and arcing which can damage both the wiring and the terminals.