Electrician advice

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LTD

LTD

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Bit of a weird one so I’d like to hear any input.

Daughter and future son-in-law have asked for my advice but I’m not sure so I thought best to ask here !!

The 45A double pole switch for their shower is showing signs of overloading (burnt internal connections and blistered internal)

It’s certainly wired correctly.

Wiuld I be right in surmising that the issue could be within the shower ?

Just want to get an idea before suggesting an electrician or plumber being the best choice
 
Poor connection closest to where the burn damage is.
Plaster dust, just dust, carbonised connection due to wear and tear....
 
LTD said:
Bit of a weird one so I’d like to hear any input.

Daughter and future son-in-law have asked for my advice but I’m not sure so I thought best to ask here !!

The 45A double pole switch for their shower is showing signs of overloading (burnt internal connections and blistered internal)

It’s certainly wired correctly.

Wiuld I be right in surmising that the issue could be within the shower ?

Just want to get an idea before suggesting an electrician or plumber being the best choice
Click to expand...
I’m not an electrician, but what rating is the shower?
Are the terminals tight?
 
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Could be loose / poor connections or sometimes the switches wear mechanically so the contacts don't strongly touch. Does the switch get turned on and off each time the shower is used? It's not being turned off under load is it?

I[ve seen electrians say that if possible they like to tighten the connections, then leave them for a bit and give them a final tighten just as the switch and its awkward cables are put in place - as the initial tightness can relax a little.

Unlikely to be an issue with the shower itself.
 
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What they all say.
poor/loose connection
Faulty/underrated switch.
I would definitely be changing the switch and see what happens.
If the shower was taking too much current for whatever reason that would show up as the rcd/rccd tripping.
 
What is the power rating of the shower ?
Is it wired in 10mm twin and earth or 6mm twin and earth ?
If its a fairly new shower could be a 10.8 kw version, if it is the 45a switch its near its limit and should need 10mm cable.
You may find you will need to upgrade to a newer 50a double pole switch.
Most problems are caused by loose connections in my experience, also check the consumer unit to see if the cable is tight and not starting to overheat there as well.
 
I’ve had this happen on a shower recently that I fitted myself, so it’s not had too much use but the switch was burnt out - a decent branded switch too.

If you search online it appears to be quite a common problem. Lots of electricians suggest not switching it on and off all the time - we leave ours on anyway - it’s only there for isolation when needed.

Ours is one of the most powerful showers and its 10mm cable. I got a new switch and i soldered the strands of the cable before refitting to try and get a better connection.

good luck with it.
 
10 mm cable is the key. 👍 check it out. And it must be the showers own separate supply from consumer unit to shower unit.
 
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Dickster said:
I got a new switch and i soldered the strands of the cable before refitting to try and get a better connection.
Click to expand...

I understand why you would think that is a good idea and I've done it myself on low current flexible cables but soldering tails for a screw connection is explicitly outlawed by the regs. The reason is thermal creep. As the connection goes through heat cool cycles the solder can creep resulting in a loose connection. I would check the connections are still tight. There is a reason why the regs require that every screwed connection must be accessible for inspection so that you can check the tightness.

On the OP's original problem I don't see how it can be anything but loose connections as the switch is never operated under load and therefore has no arc to quench.
 
replace the switch as others have said. the crabtree one is one of the better ones
www.toolstation.com

Crabtree 50A Pull Switch

www.toolstation.com www.toolstation.com
this thread discussed a similiar problem a few days ago

40 Amp Double Pole Switch - A Question for Those Versed in Such Things | OT (OFF Topic) Forums

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...
forums.mbclub.co.uk forums.mbclub.co.uk
 
Dickster said:
I’ve had this happen on a shower recently that I fitted myself, so it’s not had too much use but the switch was burnt out - a decent branded switch too.

If you search online it appears to be quite a common problem. Lots of electricians suggest not switching it on and off all the time - we leave ours on anyway - it’s only there for isolation when needed.

Ours is one of the most powerful showers and its 10mm cable. I got a new switch and i soldered the strands of the cable before refitting to try and get a better connection.

good luck with it.
Click to expand...
as 190 says soldering cable as you did is not a good idea
 
Peter103 said:
And it must be the showers own separate supply.
Click to expand...

I guess this is a standard recommendation and got raised in the survey when we bought our current house, even though the shower uses hot water from the tank and only has an 18V supply (solely for the pump) running to it from a little transformer in the loft. Requiring a dedicated supply circuit for that seemed like total overkill?
 
BTB 500 said:
I guess this is a standard recommendation and got raised in the survey when we bought our current house, even though the shower uses hot water from the tank and only has an 18V supply (solely for the pump) running to it from a little transformer in the loft. Requiring a dedicated supply circuit for that seemed like total overkill?
Click to expand...

What you have described sounds like a mixer shower rather than the electric type of shower being discussed in this thread. It's only electric showers that require an exclusive supply.
 
I changed the shower unit at daughter house a couple of years ago and it was quite tricky to get a good connection on the 6mm stranded cable without it spreading and splitting (ideally I should have used ferrules).

They use the shower a lot and it got removed the other day when they had the bathroom fitted as it was replaced by shower fed from their combi. The connections on the shower looked absolutely fine - no sense of them getting hot at all.

So from this exhaustive test I'm going to deduce that in cases where the switch overheats, it's the switch mechanism itself introducing some resistance (unless something pretty daft has been done with the connections).
 
190 said:
What you have described sounds like a mixer shower rather than the electric type of shower being discussed in this thread. It's only electric showers that require an exclusive supply.
Click to expand...

Yes I agree, but because it's powered (pumped) it was still treated as an 'electric shower' by the surveyor!
 
Rory said:
So from this exhaustive test I'm going to deduce that in cases where the switch overheats, it's the switch mechanism itself introducing some resistance (unless something pretty daft has been done with the connections).
Click to expand...
Working 6 & 10mm wires is awkward, even in a deep back box.
When trying to reassemble the plate to the back box it's easy to strain terminals and / or distort the switch mechanism.
The result of reducing the clamping on the connection or the switch not being as effective is easy.

Better to manipulate the wires, assemble and then disassemble to check again nothing is less secure.

To digress a little, when assembling similar with a socket it's easy for the 4mm screw to damage a wire. If it's the live pop, if it's neutral you wouldn't know unless there is RCB protection, which would then trip.

BTB, as your supply to the pump in the bathroom is 'Safe Extra Low Voltage' (SELV) the surveyor had no need to be concerned anyway, as the 240 volt supply to that was outside the bathroom.
 
190 said:
I understand why you would think that is a good idea and I've done it myself on low current flexible cables but soldering tails for a screw connection is explicitly outlawed by the regs. The reason is thermal creep. As the connection goes through heat cool cycles the solder can creep resulting in a loose connection. I would check the connections are still tight. There is a reason why the regs require that every screwed connection must be accessible for inspection so that you can check the tightness.

On the OP's original problem I don't see how it can be anything but loose connections as the switch is never operated under load and therefore has no arc to quench.
Click to expand...
Interesting. Thanks, I’ll keep an eye on it. 10mm cable is a nightmare to work with!
 
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