Elec Shower trips when OFF

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Hi, My electric shower keeps tripping off when its NOT being used.

It works perfectly fine, but over the last week it trips off at some stage during the day when its not in use?

It was doing this about a year ago....and then no issues again until a week ago

Thought it maybe a faulty unit (pic attached) or the fuse itself....can these individual fuses (switch on right) be changed?
 
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Burnt out connection at your pull switch or a water leak in the shower. It won't be a faulty circuit breaker.
 
Thanks for quick reply.

Was wondering if it was that again.Pull switch has been replaced 3 times in 6 years professionally by two different electricians who checked all wiring and said there were no problems....but surely if the pull switch keeps going there must be???
 
Isolate the circuit, take cover off shower case, check there for damp (which can be fixed via some sealant), also check wiring for signs of arcing / that terminals are tight.

Wires should be clean, not oxidised or arced.

If nothing obvious at shower, check shower pull switch wres and terminals.



Since the shower works and then trips after use I'd suggest water / damp ingress at shower body after shower used.
 
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Which one is tripping? I expect RCCB more well known as a RCD?

As said likely condensation some where, inspection (Power off) is first step.

Although it says shower not unknown for things like extractor fan being fed from same supply with a humidity control they can cut in at odd times.
 
Which one is tripping? I expect RCCB more well known as a RCD?
Clearly an important question. As you say, one would suspect that it's the RCD which is tripping (since MCB trips when the shower was not in use would be very unlikely) - but the situation is a bit confused by the fact that the OP has asked whether the "switch on the right" (the MCB) could be replaced.

Kind Regards, John
 
The switch that trips is the one stickered "Shower Supply"

Switch stickered "RCCB" stays ON
 
Isolate the circuit, take cover off shower case, check there for damp (which can be fixed via some sealant), also check wiring for signs of arcing / that terminals are tight.

Wires should be clean, not oxidised or arced.

If nothing obvious at shower, check shower pull switch wres and terminals.



Since the shower works and then trips after use I'd suggest water / damp ingress at shower body after shower used.

Hi Have now checked inside shower unit all very clean, wiring clean not oxidised and no sign off water leakage.

Also the checked the three times changed switch, again clean/no heat damage.

I really am baffled as two electricians have checked and said no issues but problem remains?

Time for a mixer shower I think this electric shower has been nothing but trouble!
 
The switch that trips is the one stickered "Shower Supply" ... Switch stickered "RCCB" stays ON
That's what I suspected from what you said. Given that it would take a very large current to cause that MCB to trip (if it were functioning correctly), and that it's tripping when the shower is not on (so the 'large current' would have to be going somewhere other than the shower - which would almost certainly result in 'burning'), I would think that the most likely explanation would be a faulty MCB - which is cheap and easily changed by an electrician.

Kind Regards, John
 
The switch that trips is the one stickered "Shower Supply" ... Switch stickered "RCCB" stays ON
That's what I suspected from what you said. Given that it would take a very large current to cause that MCB to trip (if it were functioning correctly), and that it's tripping when the shower is not on (so the 'large current' would have to be going somewhere other than the shower - which would almost certainly result in 'burning'), I would think that the most likely explanation would be a faulty MCB - which is cheap and easily changed by an electrician.

Kind Regards, John

Is replacing the MCB a job for an electrician not recommended for Joe Public?
 
... I would think that the most likely explanation would be a faulty MCB - which is cheap and easily changed by an electrician.
Is replacing the MCB a job for an electrician not recommended for Joe Public?
Probably not what you want to hear, but I suppose the simplest answer is that it is probably not a job for a Joe Public who needs to ask that question.

Kind Regards, John
 
Just one last thought on this......

seeing as it seems to be tripping between the isolator switch (regardless of it being on or off) and the MCB could there be a problem with condensation with the MCB box being outside in a meter cupboard?

It may just be coincidence but tripping events always seem to happen during cold spells
 
Just one last thought on this...... seeing as it seems to be tripping between the isolator switch (regardless of it being on or off) and the MCB could there be a problem with condensation with the MCB box being outside in a meter cupboard? ... It may just be coincidence but tripping events always seem to happen during cold spells
I would think that's very unlikely. As has been implied, moisture/water can easily cause an RCD to trip but not a 40A MCB - it take only a 'leakage current' of 0.03A to trip an RCD, but at least 45A to trip a correctly functioning 40A MCB.

Kind Regards, John
 
That's what I suspected from what you said. Given that it would take a very large current to cause that MCB to trip (if it were functioning correctly), and that it's tripping when the shower is not on (so the 'large current' would have to be going somewhere other than the shower - which would almost certainly result in 'burning'), I would think that the most likely explanation would be a faulty MCB - which is cheap and easily changed by an electrician.
Sorry but I can't agree with your analysis.

It would seem pretty odd to me for a MCB to trip seemingly randomly when there is no load and yet hold in when subject to pretty much full load. I guess it's not beyond the realms of possibility that there is a mechanical problem with the latch mechanism in the MCB or something which causes it to drop out randomly regardless of load but it seems unlikely to me.

I personally think the most likely explanation is that there is a wiring fault somewhere. E.g. wires that have lost their insulation or a metal object has penatrated them leading to metal which is nearly but not quite touching most of the time. In those circumstances a bit of movement of moisture (dry air has a MUCH higher breakdown voltage than damp air) could easilly be the difference between an effective open circuit and a near dead short. If you are lucky the resistance when the fault is "open" may be low enough to show up on an insulation resistance tester but if you are unlucky it may well be the only way to find the fault is an inspection of the entire length of the cicuit.

I would suggest starting with insulation resistance tests and a through inspection of all accessible parts of the circuit.
 
It is very un-likely that moisture is causing the device to trip. It would need a very large area of contact between the water and the Live conductor to allow 40+ amps to flow. A small area might allow a few amps to flow through the water but that would almost certainly create noticeable steam or other effects long before the current reached 40 amps ( image the steam from a 1 kW kettle ( 4 amps ) as it boils.

Looking at the picture there seems to be three grey cables going in the top of the unit. Could there be something else that is fed from this MCB ?
 

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