Shower circuit tripping Intermittently when NOT in use

[Rhibhi85]

Weird one and was wondering if anyone can help? I originally booked for an electrician to come and have a look but had to cancel due to being in isolation for 12 weeks (fun). Can anyone give me any ideas on what this might be? Electrician said it could just need a new pull cord switch in the bathroom but hadn’t come to look at it yet.

I have a disability wet room with electric shower that has a pull cord switch. The shower works fine, you can turn it off and on and shower without any problems. I always turn it off on the shower and then the pull switch after use.

However, every few days I go to turn it on and the pull switch doesn’t light up, I then have to go into the garage and turn it back on at the main board as the trip switch has flicked off. It then works again fine until (usually a few days later) it does it again.

The shower is on its own circuit and has its own switch in the garage on the main board.

I’ve tried narrowing it down to whether there is something I’m using during the day or morning that might be tripping it (toaster, kettle, tooth brush charging in the shaver socket in the bathroom) but nothing seems to force it to trip that I have tried. And that would seem odd if it’s on its own circuit right?

Anyone had this happen? Or have any idea what could be causing it? I’m going to get the pull cord switch replaced when I can have some in just incase but it seems odd if it’s that as it works ok once you switch it back on in the garage and then just trips again after a few days. And that’ll also be something an electrician can’t SEE happen when testing.

It Only ever trips when NOT in use and switched off at the pull switch,

Weird right??

️

Thanks in advance!

 

[Rhibhi85]

Sorry about the spelling error In the title, won’t let me change it now! Should say ‘when NOT in use’

 

[terryplumb]

What trips , RCD , MCB ,RCBO ?

 

[winston1]

Try not turning off the pull switch after using the shower. They are not meant to be turned off every time. They are isolators to be turned off when working on the shower. Of course they are also not necessary or required as one can isolate at the CU (in the garage in your case).

 

[SUNRAY]

Try not turning off the pull switch after using the shower. They are not meant to be turned off every time. They are isolators to be turned off when working on the shower. Of course they are also not necessary or required as one can isolate at the CU (in the garage in your case).

AFAIA they are necessary as the MI for every shower unit I've ever installed lists it as a requirement, therefore not fitting an isolator switch is contrary to MI and incorrectly installed.

We always isolate our electric shower, I've replaced/repaired far too many of them...

 

[Taylortwocities]

@Rhibhi85
This is the key question. Answer this and we can help more.

What trips , RCD , MCB ,RCBO ?

If you don’t know the answer, post a photo of the device that “trips”.
Or, this might help

Untitled

• Taylortwocities
• 27 Mar 2010
• 43

 

[bernardgreen]

as one can isolate at the CU

Not if the device in the CU is a single pole device ( the Neutral remains connected hence the circuit is NOT isolated )

 

[winston1]

.

 

[Taylortwocities]

Good! Thank you.

 

[Harry Bloomfield]

What happens if you leave the isolator alone - don't isolate it after use? They should be no need to isolate the shower between usage, the isolator is only there to enable the shower to be serviced, but it doesn't explain why it trips.

My shower(s on third now) have been left on for more than 40 years, only isolated for servicing.

 

[SUNRAY]

What happens if you leave the isolator alone - don't isolate it after use? They should be no need to isolate the shower between usage, the isolator is only there to enable the shower to be serviced, but it doesn't explain why it trips.

My shower(s on third now) have been left on for more than 40 years, only isolated for servicing.

Let's wait until we find out what is tripping before offering further advice.
Then for the purposes of fault finding, it's worth leaving it on for long enough to see if it helps.

In the meantime I'll add that I've known several units whose microswitchs have spontaneously made, usually the water valve. That meant either the water or the heater or both started working. But now I'm finding damp in the electronics is the problem. The resulting damage, especially water, is well worth remembering to switch off in my opinion.

 

[securespark]

It could be that the device tripping is an RCD and there is another circuit on that RCD that is the culprit?

 

[Rhibhi85]

Sorry it took a while to reply, I waited for it to trip again before going out to the garage to make sure whatever I took a picture of was accurate! Pic of what the board looks like when the shower won’t turn on.
I will try leaving it on at the cord if that might help to diagnose... but it has a big red light on it and a blue light on the shower when it’s left on so I always switch it off (probably an OCD thing from being told not to leave things on standby in order to save power!). I’m one of those freaks that turns their microwave off at the wall after every use too (mainly so I don’t ever have to get a degree to learn how to set the clock!)
Thank you for all your replies so far, a right bunch of detectives aren’t you

 

[terryplumb]

From what you have told us ,I suspect what is happening is when you switch off the ceiling pull cord switch ,that is when the MCB trips. When you next go to use the ceiling switch nothing works ,as the MCB is already off.
You could check the MCB , after switching off the ceiling switch ,each time shower is used. If it is tripping the MCB as described ,that points to a suspect ceiling switch ,possibly the MCB.
You will at some point need to engage an electrician to test and rectify.

 

[Taylortwocities]

Nice to see some cowboy crowbarring a “foreign” MCB into a different donor consumer unit.
always points towards someone with a make do attitude. the quality of the installation may prove to be the root cause of this problem.