RCD tripping when shower switch is switched on

YoTaro

Have an extension on to an old house. The extension (2 rooms and an en suite) has its own electrical board.
The shower in the en suite of the extension, which has the water coming from the hot water cylinder trips the RCD sometimes. Maybe 1 in every 10 times it is switched on.
The RCD has the shower and 2 socket mcb's on it. 
The tripping happens when the shower switch is switched on outside the bathroom door while the shower remains switched off! Which i cant understand why.
Any idea why this is happening?
Thanks for any reply

meercat

It appears to be a neutral to earth fault. The appliance does not have to be running to cause the rcd to trip. Perhaps moisture is getting in and around the connections inside the pump causing it to trip intermittently.

Sleeper12

YoTaro wrote:

Have an extension on to an old house. The extension (2 rooms and an en suite) has its own electrical board. The shower in the en suite of the extension, which has the water coming from the hot water cylinder trips the RCD sometimes. Maybe 1 in every 10 times it is switched on. The RCD has the shower and 2 socket mcb's on it. The tripping happens when the shower switch is switched on outside the bathroom door while the shower remains switched off! Which i cant understand why. Any idea why this is happening? Thanks for any reply

First off all your shower doesn't seem to tired correctly.
This should be looked at by a RECI electrician.

Second thing is that a power shower rarely trips the fuse intermittently. It's true that water could be leaking inside the shower itself but I'd bet that there is a problem with the electrical set up rather than the shower itself.

2011

Sleeper12 wrote: »

First off all your shower doesn't seem to tired correctly.

Sleeper is correct, the shower should not share an RCD with sockets. You should get a qualified electrician to look at this as there may be other issues.

The tripping issue may be due to issues with the socket circuits(s).

meercat

The op says the shower is heated from hot water cylinder so perhaps it’s only a pump he has and this is spurred off the socket rcd.
Either way a rec is recommended

2011

meercat wrote: »

The op says the shower is heated from hot water cylinder so perhaps it’s only a pump he has and this is spurred off the socket rcd.
Either way a rec is recommended

Ooops! You are correct.

Sleeper12

Have an extension on to an old house. The extension (2 rooms and an en suite) has its own electrical board.
The shower in the en suite of the extension, which has the water coming from the hot water cylinder trips the RCD sometimes. Maybe 1 in every 10 times it is switched on.
The RCD has the shower and 2 socket mcb's on it.
The tripping happens when the shower switch is switched on outside the bathroom door while the shower remains switched off! Which i cant understand why.
Any idea why this is happening?
Thanks for any reply

meercat wrote: »

The op says the shower is heated from hot water cylinder so perhaps it’s only a pump he has and this is spurred off the socket rcd.
Either way a rec is recommended

Of course you could be right. I might have jumped the gun. It's the part in bold that had me thinking an all in one power shower rather than dedicated pump. I'm thinking it unusual to have a switch just for the pump on the outside the bathroom wall

kramer1

Could be something inside the switch but most likely the shower , is it a Triton /Mira booster type deal?

YoTaro

Thanks for the replies.
It is a Triton T shower, and yes the switch is a fused switch outside the bathroom door. I have opened the shower and tried to seal it as best i can. I have also opened the switch and found nothing visibly wrong. Continuity tested the cables and no short found.
I have BASIC electrical knowledge so I was trying to figure it out just before calling the experts. 
Would it be an idea to take take the shower circuit off the RCD and put it on its own RCBO? With the view that it might be the socket circuits and shower combined causing nuisance tripping. There is enough room in the board to expand

Sleeper12

YoTaro wrote:

Thanks for the replies. It is a Triton T shower, and yes the switch is a fused switch outside the bathroom door. I have opened the shower and tried to seal it as best i can. I have also opened the switch and found nothing visibly wrong. Continuity tested the cables and no short found. I have BASIC electrical knowledge so I was trying to figure it out just before calling the experts. Would it be an idea to take take the shower circuit off the RCD and put it on its own RCBO? With the view that it might be the socket circuits and shower combined causing nuisance tripping. There is enough room in the board to expand

Unless there is evidence that water is getting into the shower then because the tripping is random I'd rule out the shower.

Is illegal for anyone but a REC to go near the fuseboad so I suggest a good electrician. If such a dangerous mistake has been made with the wiring of the shower I would want an electrician to check everything in the extention if it were my house.

The problem with dangerous wiring jobs is that they will look & work perfectly till they cau a fire or kill someone

Ginger83

Sleeper12 wrote: »

Unless there is evidence that water is getting into the shower then because the tripping is random I'd rule out the shower.

Is illegal for anyone but a REC to go near the fuseboad so I suggest a good electrician. If such a dangerous mistake has been made with the wiring of the shower I would want an electrician to check everything in the extention if it were my house.

The problem with dangerous wiring jobs is that they will look & work perfectly till they cau a fire or kill someone

I seem to have the same problem, an extension with an en-suite that has a Triton AS2000XT shower heated from the hot water cylinder. The extension has it's own fuse board and the shower has a pull cord. It trips once every three to four showers, never happens during a shower only in between showers.

Sleeper12

Ginger83 wrote:

I seem to have the same problem, an extension with an en-suite that has a Triton AS2000XT shower heated from the hot water cylinder. The extension has it's own fuse board and the shower has a pull cord. It trips once every three to four showers, never happens during a shower only in between showers.

Highly unlikely for the shower to be at fault.
I suggest that you get an electrician to check out the trip switch and the wiring.

Ginger83

Sleeper12 wrote: »

Highly unlikely for the shower to be at fault.
I suggest that you get an electrician to check out the trip switch and the wiring.

Would it be unsafe?

Sleeper12

Ginger83 wrote:

Would it be unsafe?

It all depends on why it's tripping. Sometimes you can get random tripping for no apparent reason. Sometimes changing the trip switch fixes it. But I'd imagine that it could also be faulty wiring and that should be checked out. I'm in shower repair so that is where my knowledge is. You will get better advice on the fuse & wiring from an electrician. If like the other poster your shower is on a circuit with sockets or lights then it's most likely wired incorrectly.

2011

Ginger83 wrote: »

Would it be unsafe?

Impossible to know without seeing it, but what we do know is that an important safety device keeps operating (the RCD) and mains voltage can be lethal.

YoTaro

Ginger83 wrote: »

Sleeper12 wrote: »

Unless there is evidence that water is getting into the shower then because the tripping is random I'd rule out the shower.

Is illegal for anyone but a REC to go near the fuseboad so I suggest a good electrician. If such a dangerous mistake has been made with the wiring of the shower I would want an electrician to check everything in the extention if it were my house.

The problem with dangerous wiring jobs is that they will look & work perfectly till they cau a fire or kill someone

I seem to have the same problem, an extension with an en-suite that has a Triton AS2000XT shower heated from the hot water cylinder. The extension has it's own fuse board and the shower has a pull cord. It trips once every three to four showers, never happens during a shower only in between showers.

I checked my shower for the exact model and its the same type, Triton AS2000XT. A google search seems to suggest that it is a common fault with this type of shower.
Better to get it sorted and call in the professionals

Sleeper12

YoTaro wrote:

I checked my shower for the exact model and its the same type, Triton AS2000XT. A google search seems to suggest that it is a common fault with this type of shower. Better to get it sorted and call in the professionals

I don't know of any known issue with this model shower.

Statistically random tripping is the fault of the trips switch about 99.99 percent of the time

Sleeper12

Sleeper12 wrote: »

Statistically random tripping is the fault of the trips switch about 99.99 percent of the time

Serious that's a statistic?

Nuisance tripping is not random it's cumulative earth leakage from appliances.
If it was fit for purpose it wouldn't nuisance trip.
I've never seen an RCD randomly trip. It's electro-mechanical. It either fails {(~7%) more often it fails to operate than trips below threshold} or it's an installation issue.





PS.

Sleeper12 wrote: »

Is illegal for anyone but a REC to go near the fuseboad so I suggest a good electrician.

I would not assume these are the same thing.

Sleeper12

My profession is shower repair. The AS2000XT is a power shower rather than an electric shower. Showers trip instantly and not randomly for the most part. It is possible that water is getting in to the shower, hitting an electric component & causing it to trip though this rarely happens & it's definitely not happening to all of the posters above. When I say random what I mean is not instant. If there is a short in the shower it will trips as you turn it on & should happen every time you turn it on.

Several posters have what I call random tripping. Although none have come back with an answer to their faults I'm betting it wasn't the shower. If they were electric showers I could be more certain that it's the RCBO. Many RCBOs develop this problem and become too sensitive or just start to fall. If we get a call about random tripping then with an electric shower we send an electrician to replace the RCBO. We don't send out anyone to repair the shower.

I have had three showers that I can recall in 30 years that had random tripping and it turned out to be the shower yet we have sev per week where the RCBO has become faulty and trips randomly.

EDIT:
Quote:
Originally Posted by Sleeper12 View Post

Is illegal for anyone but a REC to go near the fuseboad so I suggest a good electrician.

I would not assume these are the same thing.

I'm autistic so things don't always come out the way others would understand. "Is illegal for anyone but a REC to go near the fuseboad" I'm telling that only an REC rather than a non registered electrician can work on a fuseboard. "so I suggest a good electrician". By a good electrician I mean a good REC electrician as I have already established that only a REC can work at the fuseboard. Welcome to my world. Last week over a 12 hour period I couldn't put into words a very simple thing on valuing a business on another thread. I must have had a dozen stabs at it. A few days later someone came alone & explained it perfectly in about two sentences. Nobody got what I was saying but understood him perfectly.

It makes life interesting.

I'm a bit the same myself, hence my cascade edit phenomenon.

The two points I was making were A: there's no such thing as random tripping. It's a scientific device with a scientific explanation.

and B: there's bad RECs and good RECs. Being a REC does not mean one is talented or diligent only that they've served their time and paid their dues. I spend a lot of time fixing the work of RECs.

Sleeper12

Sir Liamalot wrote: »

I'm a bit the same myself, hence my cascade edit phenomenon.

The two points I was making were A: there's no such thing as random tripping. It's a scientific device with a scientific explanation.

and B: there's bad RECs and good RECs. Being a REC does not mean one is talented or diligent only that they've served their time and paid their dues. I spend a lot of time fixing the work of RECs.

I call it random to distinguish it from instant tripping. Instant in my own mind is when it trips as the shower turns on. Random I use when it might trip during a shower or after 4 showers. There's no need to tell you that I'm not an electrician. Instant & the issue is most likely the shower. Random & it's better to look elswhere rather than the shower unit itself. Usually the trip switch is the problem.


I'm concerned with some of the shower setups in posts above. They seem to have taken a spur off sockets or lights so I'm guessing not a good electrician. If it were my house I'd want all of the wiring checked out in the extension, all the wiring that the builders "electrician" did. Where there is one lazy mistake there is more.

I believe the word you are looking for is intermittent.

I check all my residences wiring myself. I've never been satisfied with the standard.

Agree. The shower in question ought not to be sharing an RCD and definitely not spurred from anything.

tweek84

Highly unlikely that it is a faulty RCD,
I would be looking at the wiring and the connections, i have seen it numerous times where there were poor connections on the switch for the shower causing the cable to heat up and melt cause the RCD to trip.

A 7% fail rate is very likely to me.

Conducted heat may cause an MCB or RCBO to trip. It ought have no effect on an RCD outside of heat staining.