40 Amp Double Pole Switch - A Question for Those Versed in Such Things

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whitenemesis

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I have a 40 amp double pole pull switch providing switched power to our electric shower and timed extractor fan. Said pull switch has a mechanical flag (red) and red neon lamp to indicate it's on condition.
Just recently when pulling the switch cord to energise the shower and extractor the red flag appears and the extractor runs but the neon remains off as does the shower. Pulling the cord a second time retracts the red flag, the neon and shower remain off and the extractor remains on as it should. Pulling the cord a third time the flag reappears, the neon illuminates and the shower energises. The extractor continues running.
Pull the cord a fourth time the flag retracts, the neon extinguishes and the shower goes off. The extractor runs on the desired time.

What is causing this malfunction? It is completely repeatable and one now has to pull the cord three times to get a shower!
 
Just a guess.
The contacts are rotary and connect/disconnect twice for a full rotation i.e. on/off/on/off

The first time you switch the contacts just connect enough for the extractor to trigger - it will have its own permanent supply (and timer) as well as the trigger/supply from the switch.

Next phase is off

Next phase the contacts fully connect

Next phase is off.

As I say - just a guess.
 
Mmm sounds very logical..
Guess a new switch before Mrs WN rips the cord off ...
 
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Mmm sounds very logical..
Guess a new switch before Mrs WN rips the cord off ...
Yep, replace the switch.
I was away from home for a week when similar problem occurred on a bathroom light pull cord switch. Bathroom also had separate lights round a mirror which were still operational.
Needed a new £2 switch when I returned.
But no, SWMBO called in an emergency electrician :doh: :wallbash:
 
I'm just about to fit a 40 amp double pole isolation switch to an electric shower and I've opted for a wall switch just outside the bathroom door for simplicity. I'm not as up to date with the regs as I once was but if I'm not mistaken it should not supply any other device such as an extract fan which I will be feeding via the light switch in the normal way.
 
It’s failing.
Screwfix do a 50A one for about £10.

Turn the power of at your CU before you touch anything.

When you start opening it, photo the wiring/ make a list of which colours etc go to which terminal, so you can replicate it on the new switch.

If you are unsure, get an electrician.
It can be lethal.
It can be a fire risk.
 
I'm just about to fit a 40 amp double pole isolation switch to an electric shower and I've opted for a wall switch just outside the bathroom door for simplicity. I'm not as up to date with the regs as I once was but if I'm not mistaken it should not supply any other device such as an extract fan which I will be feeding via the light switch in the normal way.
What is the power of your shower? 40A only good up to 9kw.
 
I fitted it myself about 5yrs ago, not much room for those thick cables. Wasn't aware one shouldn't also feed the extractor. It's only the trigger for the timer not the motor loading
 
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What is the power of your shower? 40A only good up to 9kw.

It's 8.5 kw and at the end of 25M of 6mm2 cable it won't even draw that. This shower is in a spare bathroom and won't be used much at all so I wasn't fussed about how powerful it was. I particularly didn't want to struggle with 10mm2 cable either. The 6mm2 is surface clipped in free air all the way expect for the drop to the shower and isolation switch where it is behind plasterboard and in an air space. It'll be fine, I've done the voltage drop calcs.
 
When you start opening it, photo the wiring/ make a list of which colours etc go to which terminal, so you can replicate it on the new switch.

If you are unsure, get an electrician.
It can be lethal.
It can be a fire risk.
Unlike the plasterer who did the ceiling at a friends....rewired the light fitting to the permanent lives in the loop rather than the switch wire.. fail
 
this sparky also rates the crabtree switch highly and in this video he explains why he (and I ) like them for the ease of wiring. the bit describing the switch is at 11.42 in
if you can arrange for the cables to come down either side of a joist it also means that you get a good fixing into the centre of the joist

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The Crabtree switch arrived today and what a joy to fit! :banana:
My word it's big! Plenty of wriggle room for those big cables, very secure terminals and nicely thought out cap/indicator/neon.
Easily covered the old fixing marks, screwed directly into the joist. Job done!
@flying haggis Thanks for the heads-up :thumb:
 

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