Elec Shower trips when OFF

[deadshort]

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?

Untitled

• Aquaman
• 5 Jan 2015
• 1

I have had a similar situation on a shower rcd in a small block of flats, it transpired that the immersion heater in the flat above had burnt out and caused a earth leakage on the rising water main between the two flats which was tripping the shower circuit even when it was switched off.

 

[canduit]

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?

Untitled

• Aquaman
• 5 Jan 2015
• 1

I have had a similar situation on a shower rcd in a small block of flats, it transpired that the immersion heater in the flat above had burnt out and caused a earth leakage on the rising water main between the two flats which was tripping the shower circuit even when it was switched off.

But the MCB is tripping here, not the RCD

 

[deadshort]

And i thought i had problems ! Very odd

Regards,

DS

 

[JohnW2]

If he knows it's tripped because the power light goes out , doesn't that mean he's not turning off at the ceiling pull switch and it's live as far as the shower until the breaker trips?

That is my understanding of the situation.

II was thinking it was tripping with the ceiling switch off but maybe I'm being dense

Not dense ... until recent posts from OP, we were not sure about this.

Kind Regards, John

 

[Aquaman]

If he knows it's tripped because the power light goes out , doesn't that mean he's not turning off at the ceiling pull switch and it's live as far as the shower until the breaker trips? I was thinking it was tripping with the ceiling switch off but maybe I'm being dense

Hi Dave, Just to clarify:

1: Shower turned off at unit - then pull switch turned off = tripped by next time pull switch is turned on

2: Shower turned off at unit - pull switch left on = trips (sometimes 1 hour plus later, sometimes doesn't trip)

 

[ban-all-sheds]

What do you see on the meter for rate of consumption when the shower is on and when it is off?

 

[Craig_r]

Hi Dave, Just to clarify:

1: Shower turned off at unit - then pull switch turned off = tripped by next time pull switch is turned on

2: Shower turned off at unit - pull switch left on = trips (sometimes 1 hour plus later, sometimes doesn't trip)

In scenario 1, at what point do you realist that it has tripped?

Have you checked the MCB before turning on the ceiling pull switch, or only after you have turned on the ceiling pull switch and the neon light doesn't come on?

 

[JohnW2]

1: Shower turned off at unit - then pull switch turned off = tripped by next time pull switch is turned on
2: Shower turned off at unit - pull switch left on = trips (sometimes 1 hour plus later, sometimes doesn't trip)

In scenario 1, at what point do you realist that it has tripped? ... Have you checked the MCB before turning on the ceiling pull switch, or only after you have turned on the ceiling pull switch and the neon light doesn't come on?

Indeed - that's essentially a variant of questions I've previously asked the OP. It would obviously be potentially pertinent if it were possible that the MCB is tripping when the pull switch is operated. However, no matter what his answer to that question, we will still be left with mysterious scenario (2) - which,if I understand correctly, is that the neons on both pull switch and shower go out (indicating that the MCB has tripped) when absolutely nothing has been done since the shower was last working.

Kind Regards, John

 

[EFLImpudence]

Faulty cable - being squashed under the floor, touching heating and expanding pipes, being moved by rodents.

The only difference switching off the isolator makes is indicating which cable is faulting.

Or, as said, faulty MCB.

 

[JohnW2]

Faulty cable - being squashed under the floor, touching heating and expanding pipes, being moved by rodents. ...

Nothing's impossible - but I still think that it's pretty unlikely that sort of fault would result in repeated (but seemingly fairly random) trips of a B40 (with nothing else 'happening'), particularly given that the associated RCD never operates.

The only difference switching off the isolator makes is indicating which cable is faulting.

...unless the fault were in the isolator itself.

Or, as said, faulty MCB.

Even though it's pretty unusual behaviour for even a faulty MCB, I have to say that my money is still on that - as the 'least unlikely' of the possibilities!

As I've said, if the circuit IRs OK (which clearly wouldn't mean much, given the intermittent nature of the problem), I would be very much inclined to just change the MCB. That would cost little money or time, and it seems that the trips are sufficiently frequent that it would quickly become apparent whether or not this had cured the problem. If it did solve the problem, one could then perhaps avoid exposing all of the cable (which could be very disruptive) in the search for a hypothesised fault which may well not exist.

Kind Regards, John

 

[EFLImpudence]

Faulty RCD as well.

(Has it been said? Can't remember)

 

[JohnW2]

Faulty RCD as well. (Has it been said? Can't remember)

No, I don't think that possibility has been raised - but I suppose it's not impossibile. I therefore probably should have said that if the circuit IRs OK and the RCD tests OK, I would then be inclined to undertake a diagnostic (and, perhaps, curative) replacement of the MCB!

Aquaman: Can you confirm that the RCD trips when you press its 'Test' button? Although that is not a substitute for proper testing, such as your electrician would do, it's certainly a start!

Kind Regards, John

 

[Aquaman]

Yep....rcd trips when test button pressed

 

[JohnW2]

Yep....rcd trips when test button pressed

Thanks. Although, as I said, that doesn't prove that the RCD is functioning totally correctly, I think it goes a long way to help. I have to say that, if the RCD is at least working to the extent that it is responding correctly to the test button, it would take a pretty 'extraordinary' (albeit not impossible!) fault due to cable damage (as has been suggested) to result in repeated MCB trips without the RCD ever tripping.

Although it's sufficiently unusual behaviour that I'm far from comfortable with my suggestion, you know what I believe to be the "least unlikely" of the possible causes of what you are experiencing!

Kind Regards, John

 

[Aquaman]

I have visually checked the length of wiring as well now and can find no issues.

Decided to change the isolator switch (again!) this time for a 50amp MK.

If issue persists after this will call in an electrician (again!) to check and maybe change the MCB.