Washing machine intermittently trips RCD. Manufacturer declares machine fault-free and suggests faulty home electrics. What should I do?

[GreenGoblin]

Hi

I don’t know how resolve this so any helpful advice would be greatly appreciated. I have no electrical knowledge. I will try to be as clear and detailed as I can.

I’ve got a Bosch washing machine that’s two-and-a-half years old. Until early June, the machine has been flawless. But in June, my machine began intermittently tripping the electrics. At first it was one trip during the two hour cycle every couple of weeks, but this gradually grew to one trip almost every time I used it.

Naturally I presumed it was a fault with the machine because I don’t get any electrical trips when the machine is not in use. So I called Bosch and arranged an engineer visit. The engineer came and began by checking the mains power socket by plugging in a device with a bunch of LEDs on it. It didn’t show any faults. He then did some tests to rule out faults with the machine's major components (namely the motor and heating element).

He then unplugged the machine, pulled it out, took the back panel off and looked inside. After doing this, he said he couldn’t find any faults with the machine and suggested that the dedicated mains socket (for the machine) was faulty. Now this Bosch engineer had previously visited me two years ago when I had the same problem with my previous Bosch washer. Back then he also declared the machine fault free and said it was my mains socket at fault. He explained that the wires are likely worn out and this is causing the trip.

So I reminded him that he gave me the same excuse two years ago and asked him how my current washer was able to run for over two years without any problems. He said the wires inside the socket can get worn out, but sometimes it can keep working. I didn’t accept this explanation and asked him to remove the top panel of the machine to inspect the wires properly. He said he didn’t to do this and this started an argument. Anyway he ended up storming out.

I contacted Bosch and explained that I disagreed with the engineer’s conclusion and explained that I felt he didn’t inspect the machine properly. Bosch referred my case to their technical department and they came back and said that in their view the machine was inspected properly and is fault free. They said if the problem was with the machine the trips would be more frequent. Bosch said the likely cause of my problem is something called “nuisance tripping” as a result of earth leakage. They said I should contact an electrician and ensure that an RCD is fitted with a unit that has a symbol that I can best describe as two curly lines (my RCD doesn’t have this symbol).

Bosch told me I could get a second opinion from a second engineer, but that they stand by their technical department’s and the visiting engineer’s evaluation. I said I would be in touch when I had video evidence of the machine tripping.

From the day of the engineer’s visit (14 June), I filmed every last 30 minutes of the wash cycle as the tripping usually happens during this phase (where it goes through two rinse cycles, followed by a final spin) hoping to catch the fault on video and nothing happened. I filmed for two months and stopped a couple of weeks ago, having come to the conclusion that the fault had miraculously resolved itself.

Then today I run the machine and it trips the mains just as it was about start up its final spin. I reset the RCD and it completed the cycle from where it was interrupted. I just don’t know what to do now. I’m convinced the fault lies with the machine itself because my mains only trips when it is in operation. Nothing has changed in the last two months in terms of my electrical setup. A fault with the machine seems like the most obvious explanation. What I don’t get is why I had no problems since the engineer’s visit. If it really were the mains socket or my RCD, then how could I go 8 weeks using the machine without any trips?

I don’t know whether I should go back to Bosch or get an electrician to look at the RCD. Both will cost me (my machine is out of warranty). My questions are:

1. Where do you think the fault likely lies based on what I have described? Do you think it’s the machine or the RCD /electrics in my home?

2. Why do you think I have been able to get two months of fault free washing since the engineer’s visit? The engineer unplugged the machine during his visit. Could this have “disrupted” any earth leakage issues and given me some temporary relief from the intermittent tripping? (Usually the machine is permanently plugged into its dedicated mains socket.)

3. Do you think I should get in touch with an electrician or go back to Bosch and insist that there is a fault. I plan to start filming the machine again from tomorrow to get video evidence of it tripping during operation.


If you need any further information, feel free to ask.

I’d be grateful for any suggestions.

 

[GreenGoblin]

Try this now: Leave breaker A on, switch off B, do you have power to the w/machine?

Just done this and I can confirm I still have power to the washing machine.

 

[pc1966]

The machine and all the kitchen appliances apart from the boiler are covered the 32A circuit breaker on the far left (labelled A). The actual breaker (also 32A) that trips when the machine is on is the one next to it (second from left, labelled B). It is responsible for

If it is the 32A MCB tripping and not the one that the washing machine is on that is worrying. That sounds like a loose connection somewhere that is being shaken by the start of the cycle and shorting something out

 

[Pretty Mouth]

Now this: Switch off A, switch on B, do you have power to the W/M?

 

[GreenGoblin]

If it is the 32A MCB tripping and not the one that the washing machine is on that is worrying. That sounds like a loose connection somewhere that is being shaken by the start of the cycle and shorting something out

Do you mean a loose connection inside the washing machine? Or on my electrical system?

Now this: Switch off A, switch on B, do you have power to the W/M?

I tried that yesterday when I was working out which circuit breaker is responsible for each set of sockets and lights. I can confirm that when I switch off A and leave B on, I have no power to the washing machine.

 

[Dartlec]

Here is picture of my unit. Sorry about the quality - the lighting is not very good at the moment. I will try to get a better picture tomorrow during the day. The machine and all the kitchen appliances apart from the boiler are covered the 32A circuit breaker on the far left (labelled A). The actual breaker (also 32A) that trips when the machine is on is the one next to it (second from left, labelled B). It is responsible for all the devices I listed in my earlier post:

Thanks - the picture definitely helps.

There may have been some confusion with definitions.

If the breaker B trips, even though Breaker A appears to supply the power to the washing machine then (assuming it's not just coincidental which seems unlikely) there is either a mis wiring between the circuits which needs to be fixed, or the vibration of the washing machine is disturbing a fault in the cable for the other circuit. (Or both)

Both would need diagnosing on site by an electrician with the right test equipment.

It is possible that the neutrals are not correctly split between breakers A and B. If that is the case, then circuit B could still be 'live' when breaker B is off, or vice versa with A.

Therefore until you can get it inspected, don't assume that either circuit is electrically isolated unless the RCD is off, even if the appliances plugged into it aren't working..

 

[Pretty Mouth]

Ok. As the breaker that is tripping is not the one that is powering the w/machine, there is some problem with your electrical installation. Call an electrician in to fix it. Explain when the trip occurs, which breaker trips, that the rcd trips also, and which breaker apparently powers the washing machine. (S)he will do the rest. Good luck.

 

[GreenGoblin]

Thanks - the picture definitely helps.

There may have been some confusion with definitions.

If the breaker B trips, even though Breaker A appears to supply the power to the washing machine then (assuming it's not just coincidental which seems unlikely) there is either a mis wiring between the circuits which needs to be fixed, or the vibration of the washing machine is disturbing a fault in the cable for the other circuit. (Or both)

Both would need diagnosing on site by an electrician with the right test equipment.

It is possible that the neutrals are not correctly split between breakers A and B. If that is the case, then circuit B could still be 'live' when breaker B is off, or vice versa with A.

Therefore until you can get it inspected, don't assume that either circuit is electrically isolated unless the RCD is off, even if the appliances plugged into it aren't working..

Thank you.
My kitchen work top is an L shape. The machine is located under the short side of the "L". The single dedicated mains socket for the machine is located in the corner of the L. There is wooden panel (it's part of the kitchen unit) separating the socket and the machine. Do you think the vibration of the machine could still affect the mains socket? The actual RCD box is located on the opposite side wall of the machine (away from the machine).
Should I definitely forget about going to Bosch? Can I still use the machine? I used it yesterday and it didn't trip.

 

[Pretty Mouth]

Thank you.
My kitchen work top is an L shape. The machine is located under the short side of the "L". The single dedicated mains socket for the machine is located in the corner of the L. There is wooden panel (it's part of the kitchen unit) separating the socket and the machine. Do you think the vibration of the machine could still affect the mains socket? The actual RCD box is located on the opposite side wall of the machine (away from the machine).
Should I definitely forget about going to Bosch? Can I still use the machine? I used it yesterday and it didn't trip.

Leave Bosch alone. You have a problem with your electrical installation. Get an electrician.

 

[Dartlec]

Thank you.
My kitchen work top is an L shape. The machine is located under the short side of the "L". The single dedicated mains socket for the machine is located in the corner of the L. There is wooden panel (it's part of the kitchen unit) separating the socket and the machine. Do you think the vibration of the machine could still affect the mains socket? The actual RCD box is located on the opposite side wall of the machine (away from the machine).
Should I definitely forget about going to Bosch? Can I still use the machine? I used it yesterday and it didn't trip.

I would say at least until the wiring is clarified it's not worth going to Bosch. The issue with the breakers may or may be relevant to the washing machine but needs to be sorted and they will do nothing if they can in any way pin it on the installation anyway.

The consumer unit appears to be old but a good brand and well installed with isolator etc, so it may well be something simple. Has the wiring for the kitchen been 'upgraded' at any point by a kitchen fitter or similar? Is it a solid floor? or could there be hidden junction boxes etc below the floor or on joists that might be affected by vibration?

There may be multiple causes/faults occurring here so it is hard to give an opinion on continued use, although the RCD protection reduces the risk to some extent (assuming it continues to work correctly)

A Breaker (MCB) tripping more than once is usually a more significant fault than the intermittent RCD type fault and that should be of concern, so I would be getting an electrician to look at it sooner rather than later.

 

[pc1966]

Do you mean a loose connection inside the washing machine? Or on my electrical system?

In your wiring (or just possibly in another appliance, but very unlikely as repeatedly tripping a 32A breaker would cause a 13A fuse to fail very quickly).

My own suspicion is there is a loose wire in the back of one of the sockets on the circuit 'B' that is tripping, and it is the vibration from the machine starting a spin that is triggering the fault. So probably it is a socket (or maybe junction box) that is physically close to the machine to be disturbed.

But as already said above, it really needs an electrician to visit and check things out!

 

[GreenGoblin]

I would say at least until the wiring is clarified it's not worth going to Bosch. The issue with the breakers may or may be relevant to the washing machine but needs to be sorted and they will do nothing if they can in any way pin it on the installation anyway.

The consumer unit appears to be old but a good brand and well installed with isolator etc, so it may well be something simple. Has the wiring for the kitchen been 'upgraded' at any point by a kitchen fitter or similar? Is it a solid floor? or could there be hidden junction boxes etc below the floor or on joists that might be affected by vibration?

There may be multiple causes/faults occurring here so it is hard to give an opinion on continued use, although the RCD protection reduces the risk to some extent (assuming it continues to work correctly)

A Breaker (MCB) tripping more than once is usually a more significant fault than the intermittent RCD type fault and that should be of concern, so I would be getting an electrician to look at it sooner rather than later.

I really appreciate the advice. Based on what you and others have said, I'm not going to bother Bosch again. I've not done anything myself to the wiring in the 16 years I've been here. The machine sits on a solid tiled floor in the kitchen. There is some visible vibration on the machine when the starts to ramp up or slows down, but this same machine for going for two years in the same location without tripping. Perhaps it gradually slightly moved out of place over the years and this is causing problems. I just don't know.

I plan to book the electrician in for Thursday, but I desperately need to use the machine tomorrow. I was just hoping it would be okay to use for one more wash before the electrician looks at it. I guess I'll have to think about whether it's worth taking the risk.

Anyway it's pretty clear I need to get it looked at. I don't know anyone else that I could ask for advice, so I am really grateful for all the advice from you and others in this thread.
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In your wiring (or just possibly in another appliance, but very unlikely as repeatedly tripping a 32A breaker would cause a 13A fuse to fail very quickly).

My own suspicion is there is a loose wire in the back of one of the sockets on the circuit 'B' that is tripping, and it is the vibration from the machine starting a spin that is triggering the fault. So probably it is a socket (or maybe junction box) that is physically close to the machine to be disturbed.
But as already said above, it really needs an electrician to visit and check things out!

Thing is, all the sockets on circuit B are located in the hall, my bedroom and the living room (based on my investigation). The sockets in the kitchen (including the one that the machine is on) are all on circuit A, so I don't understand how circuit B's sockets could be disturbed by the vibration from the machine when none of them are located near the machine.

But as you say, it's best to get the electrician in. Thanks for your thoughts.

 

[Dartlec]

I really appreciate the advice. Based on what you and others have said, I'm not going to bother Bosch again. I've not done anything myself to the wiring in the 16 years I've been here. The machine sits on a solid tiled floor in the kitchen. There is some visible vibration on the machine when the starts to ramp up or slows down, but this same machine for going for two years in the same location without tripping. Perhaps it gradually slightly moved out of place over the years and this is causing problems. I just don't know.

I plan to book the electrician in for Thursday, but I desperately need to use the machine tomorrow. I was just hoping it would be okay to use for one more wash before the electrician looks at it. It's pretty clear I need to get it looked at. I don't know anyone else that I could ask for advice, so I am really grateful for the advice from you and others in this thread.

It sounds like it may be the vibration that causes the issue, so is it possible to use the machine on a cycle without the spin?

Obviously noone can guarantee that using it once more wouldn't cause a further problem. However, turning breaker B off before you run the washing machine would seem to minimise the risk of the fault occuring on that circut, especially if it is vibration causing the problem, and not interlinked wiring (though it may still trip the RCD).

 

[pc1966]

Thing is, all the sockets on circuit B are located in the hall, my bedroom and the living room (based on my investigation). The sockets in the kitchen (including the one that the machine is on) are all on circuit A, so I don't understand how circuit B's sockets could be disturbed by the vibration from the machine when none of them are located near the machine.

Do you know if the cables might run through/past the kitchen area (based on where the CU is located)?

Also there is rarely much vibration is houses to match a washing machine starting spin, so even though it is a few meters away it might just be enough to case the problem.

As above, it is probably OK to use the machine tomorrow but I would not run it unsupervised just in case.

Hopefully you can let us know what is found & fixed?

 

[GreenGoblin]

It sounds like it may be the vibration that causes the issue, so is it possible to use the machine on a cycle without the spin?

Obviously noone can guarantee that using it once more wouldn't cause a further problem. However, turning breaker B off before you run the washing machine would seem to minimise the risk of the fault occuring on that circut, especially if it is vibration causing the problem, and not interlinked wiring (though it may still trip the RCD).

Thanks. I'd be running a full wash cycle so spins would be unavoidable. I will give it some thought overnight and see whether it's worth taking the risk. On the positive side, at least I now know the next step I need to take in regard to solving the problem.

 

[Dartlec]

Thing is, all the sockets on circuit B are located in the hall, my bedroom and the living room (based on my investigation). The sockets in the kitchen (including the one that the machine is on) are all on circuit A, so I don't understand how circuit B's sockets could be disturbed by the vibration from the machine when none of them are located near the machine.

But as you say, it's best to get the electrician in. Thanks for your thoughts.

It's weird for sure, so when you get to the bottom of it we'd appreciate an update, as it helps everyone know if anything similar occurs in the future

Maybe there is a structural beam/joist that is being shaken enough to tranfer the energy to another socket on or near the far end of it. Or perhaps the wiring is such that the circuits are interlinked when they shouldn't be (though that wouldn't explain the breaker tripping by itself)

On the plus side, some of the identification you have should make the visiting electrician's life simpler. I would advice making a list of what is on each circuit, and fixing it next to the consumer unit for future reference.

 

[GreenGoblin]

Do you know if the cables might run through/past the kitchen area (based on where the CU is located)?

Also there is rarely much vibration is houses to match a washing machine starting spin, so even though it is a few meters away it might just be enough to case the problem.

As above, it is probably OK to use the machine tomorrow but I would not run it unsupervised just in case.

Hopefully you can let us know what is found & fixed?

The CU is located in the kitchen on the opposite wall of the machine. If you could imagine an L shape worktop, the machine is under the short side of the L and the CU is on the opposite wall (imagine another short line at the top of the L). My home is an ex-council 2-bed flat so it's a very small kitchen. There's wiring in a slim plastic sheath running across the walls into the CU, but from what I can see, it's well away from the machine.
As I live in a block with other residents, I'm always present when I use the machine and I never use it at night or if I am going to sleep.
I'll definitely update the thread once I've got it fixed.

 

[nicebutdim]

Perhaps the OP could clarify one piece of information?

I understand from what has been posted, that the tripping occurs as the machine is about to start it's final spin and not while the spin is underway. I can't help wondering about this...

 

[static zap]

Is there a pattern - only occurs with heavy loads ,
do you have any , slower spin cycles that can be selected .
(is it a Softener Fill cycle -- sound from drawer may be different ?)