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.

 

[Dartlec]

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).

On just this small point of your post, this is probably a red herring.

There are several types of RCD - these are the most common you see in domestic, with AC being the most common until recently:

(Edit: fixed pic)

Some modern washing machines using inverter drives etc, can cause the AC type to not trip as quickly as they they should, because of the DC on the circuit. However, this is the opposite of what you are experiencing. Type A are generally recommended now because they can cope with this.

I'm not aware of washing machines being more likely to trip AC RCDs, though others more knowledgeable may know otherwise.
[automerge]1598899723[/automerge]

Hi thanks
This morning I decided to find out which circuits my devices and appliances are on. My RCD is only labelled with A,B,C,D and numbers. So it was difficult to figure which circuit breaker is responsible for what.
The big thing I've learned today is that all the appliances in the kitchen (microwave, boiler, kettle, washing machine, and fridge, and a small lamp) are all on one circuit breaker. BUT this is not the circuit breaker that trips. All this time I presumed the circuit breaker that trips was responsible for the machine and all the appliances in the kitchen, but it's not the one that trips.

The circuit breaker that trips covers the following:
Wireless router, 19" flat panel TV, small speakers and subwoofer (all three are connected via a four plug extension and are always on/standby)
BT cordless phone main base unit (plugged directly into a mains socket and always on)
Smartphone charger (always plugged in, but turned off at the mains)
Small decorative lamp with five lights, but only one bulb installed (always plugged and switched on at the mains, but never in operation while the machine is running)
Small DAB radio (always plugged in, but turned off at the mains socket)
A small low power single bulb lamp and BT cordless phone charge station (connected via a four plug extension. Always on at the mains. Phone charge station is always on, lamp rarely used never in operation when the washing machine is on)

That's everything that's plugged into the circuit that trips.

A picture of the board would really help. But does the washing machine not turn off when things 'trip'? If it does, then it must be covered by the RCD.

An RCD can cover several 'breakers' and circuits though.

If the washing machine stays on when the RCD/circuit breaker trips, then there is definitely something wrong with the house wiring (or vibration of a nearby cable by the washing machine, so indirect cause as has been mentioned)

 

[Lucien Nunes]

There is an important contradiction in your info that makes it impossible to advise further without clarification.

In post #1 you said:

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.

Indicating that the RCD that trips feeds the circuit that the machine is on.

In post #24 you said:

I've just discovered today that the actual circuit breaker that trips isn't the one covering the circuit that the washing machine or any of the kitchen appliances are on.

Either the cycle was interrupted by the breaker tripping or it wasn't. The diagnoses are completely different.

It is possible for an appliance to trip an RCD that does not feed it. The implications are:
1. The likely cause is a neutral-earth fault on a circuit protected by the RCD that trips. It could be in the wiring or an appliance plugged in, which need not be switched on.
2. There is no indication of a problem with the appliance that triggers the trip event, nor the circuit that it is plugged into. It is simply the peak load current (not earth leakage) of the appliance causing the remote, faulty circuit to leak to earth.
3. An electrical test of the affected circuits will almost certainly locate it at once.

I know what my next move would be...

 

[GreenGoblin]

On just this small point of your post, this is probably a red herring.

There are several types of RCD - these are the most common you see in domestic, with AC being the most common until recently:

View attachment 60516 (Edit: fixed pic)

Some modern washing machines using inverter drives etc, can cause the AC type to not trip as quickly as they they should, because of the DC on the circuit. However, this is the opposite of what you are experiencing. Type A are generally recommended now because they can cope with this.

I'm not aware of washing machines being more likely to trip AC RCDs, though others more knowledgeable may know otherwise.
[automerge]1598899723[/automerge]

A picture of the board would really help. But does the washing machine not turn off when things 'trip'? If it does, then it must be covered by the RCD.

An RCD can cover several 'breakers' and circuits though.

If the washing machine stays on when the RCD/circuit breaker trips, then there is definitely something wrong with the house wiring (or vibration of a nearby cable by the washing machine, so indirect cause as has been mentioned)

Hi, apologies for the delayed reply.
I was advised by Bosch's technical department to have an RCD with the symbol under the A in your picture. My RCD doesn't have this symbol. I will attempt to get a picture of it.
I can confirm that the washing machine turns off when it trips. What I discovered yesterday was that the washing machine, microwave, kettle, fridge are all on one circuit. But the circuit breaker for this circuit isn't the one that is tripping. My board isn't labelled with "kitchen", "bathroom", "living room", etc. so I had to manually work out what was on each circuit (I didn't do this in all the years I lived here).

What I found was that the circuit breaker that trips when machine is in operation is not the circuit breaker that covers the circuit that the machine is on.

Those electrical devices I listed in my previous post are on the circuit with the breaker that trips. So that's why I am confused because up until yesterday, I thought the breaker that trips is the one responsible for protecting the circuit that the machine is on, but that isn't the case.

Yesterday afternoon, Apart from my TV, wireless router, and speakers, I unplugged all the devices on the circuit with the breaker that trips and ran the machine on a full load two hour 60C wash cycle, followed by an 800rpm spin. It completed both programs without tripping.

What I am confused about is that I only get trips when the machine is in operation. When the machine is not in use everything is fine - no nuisance trips, nothing. Logically when the machine trips the circuit breaker responsible for the circuit that the machine is on should also trip and cut the power. But the circuit breaker that trips and cuts the power is the one responsible for the circuit for those devices I listed in my previous post.

What I wanted to know is can the machine cause the circuit breaker on another circuit to trip? If there is a fault with the machine itself or the circuit that the machine is on, then surely the breaker for machine's circuit should trip. Instead the breaker with all those lower power devices I listed trips and cuts the power.

There is an important contradiction in your info that makes it impossible to advise further without clarification.

In post #1 you said:

Indicating that the RCD that trips feeds the circuit that the machine is on.

In post #24 you said:


Either the cycle was interrupted by the breaker tripping or it wasn't. The diagnoses are completely different.

It is possible for an appliance to trip an RCD that does not feed it. The implications are:
1. The likely cause is a neutral-earth fault on a circuit protected by the RCD that trips. It could be in the wiring or an appliance plugged in, which need not be switched on.
2. There is no indication of a problem with the appliance that triggers the trip event, nor the circuit that it is plugged into. It is simply the peak load current (not earth leakage) of the appliance causing the remote, faulty circuit to leak to earth.
3. An electrical test of the affected circuits will almost certainly locate it at once.

I know what my next move would be...

Hi, sorry for the delayed reply.

Up until yesterday I presumed that the circuit breaker that was tripping every time was responsible for the circuit that the washing machine is on. The breakers aren't labelled and in all the years I've lived here I never bothered to work out which breaker is responsible for which set of sockets and lights, etc. in my home.

I decided to do this yesterday morning and I discovered that the microwave, washing machine, kettle and fridge all sit on one circuit, but the actual breaker that trips when the machine is in operation isn't the one responsible for the circuit that the machine is on.
Instead the breaker that actually trips and cuts the power is the one responsible for the circuit that all those devices I listed in my previous post are on.

I only have this intermittent tripping problem whenever the machine is in operation and when it is in the last 30 minutes of the two hour wash cycle. It can't just be a coincidence that I only get a trip when the machine is in use.

From what I've worked out yesterday, I found that the breaker that trips definitely isn't the one responsible for covering the machine.

The machine still loses power and goes off, but the breaker that actually trips covers a different circuit (the one with all those low power devices I listed).
Logically shouldn't the breaker for the machine's circuit trip if there is an issue with the washing machine?

I don't what to make of it. Could it be that there is a lot earth leakage from one or more of those low power devices and the machine's "natural leakage" causes the breaker on the other circuit to trip?

I didn't think this was possible, but from reading your post it sounds like it is possible for the machine to trip the breaker on another circuit.

I guess the next step isn't going back to Bosch, but calling electrician to find out what's going on.

Many thanks

 

[pc1966]

From what I've worked out yesterday, I found that the breaker that trips definitely isn't the one responsible for covering the machine.

The machine still loses power and goes off, but the breaker that actually trips covers a different circuit (the one with all those low power devices I listed).
Logically shouldn't the breaker for the machine's circuit trip if there is an issue with the washing machine?

In many CU (consumer unit = fuse box) there are two types of breaker:

• One or two RCD (residual current device) to trip on earth leakage, generally electric shock risk
• 4-12 or so MCB (miniature circuit breaker) to trip on overload, typically a hard fault fire risk

So you will often find one RCD feeds several MCB, and you can turn of each circuit separately via the MCB, but if you do that to the RCD (e.g. the test button) then several circuits go off at once.

I don't what to make of it. Could it be that there is a lot earth leakage from one or more of those low power devices and the machine's "natural leakage" causes the breaker on the other circuit to trip?

I didn't think this was possible, but from reading your post it sounds like it is possible for the machine to trip the breaker on another circuit.

I guess the next step isn't going back to Bosch, but calling electrician to find out what's going on.

The unfortunate thing above the above arrangement is the RCD will trip if it sees somewhere between 15-30mA (1mA = 0.001A) going astray, and that can be due to various reasons that are a fault (bad cable insulation, water getting in to a junction box or socket, etc). But also many electronic items have filters in them that leak 1-2mA normally, so if you have enough items on a circuit it can be prone to such trips.

A good electrician should be able to verify the RCD and you cable, etc, is working correctly. That is the first step in doing any sort of corrective work.

If that checks out OK, then some can also do PAT testing of appliances to see if any are unusually leaky. If so you might decide to replace it.

But the other option that would normally be suggested on here would be to put the washing machine and related appliances on a separate RCD, so hopefully the total that is worrying close to the 15-30mA trip range is then split in two, and both are below the trip point.

How easy and cost-effective that is would depend on your CU, if it has the space and if it is recent enough that new compatible parts are still available.
[automerge]1598980551[/automerge]
Can you post a photo of your CU?

If it has any personal information on it then please blank that out, but what is of interest is the view of the MCB/RCD, not any labels.
[automerge]1598980881[/automerge]
I can't find the clear explanation I saw before, but this explains a bit about RCD:

How do RCDs and GFIs work?

How circuit breakers switch off dangerous electric currents and save your life.

www.explainthatstuff.com

Probably others will have a better site to link to.
[automerge]1598981695[/automerge]
Another point is many appliances are left powered on at the mains but in stand-by, in these cases they often have as much leakage as when fully operating. So if you are in an unfortunate position of total leakage close to RCD trip and can't afford to make the sort of changes needed to fully fix things to be reliable, you would have to actually turn the unused appliances off at the mains socket.

Obviously not things like the fridge though that need to be left on!

 

[GreenGoblin]

In many CU (consumer unit = fuse box) there are two types of breaker:

• One or two RCD (residual current device) to trip on earth leakage, generally electric shock risk
• 4-12 or so MCB (miniature circuit breaker) to trip on overload, typically a hard fault fire risk

So you will often find one RCD feeds several MCB, and you can turn of each circuit separately via the MCB, but if you do that to the RCD (e.g. the test button) then several circuits go off at once.


The unfortunate thing above the above arrangement is the RCD will trip if it sees somewhere between 15-30mA (1mA = 0.001A) going astray, and that can be due to various reasons that are a fault (bad cable insulation, water getting in to a junction box or socket, etc). But also many electronic items have filters in them that leak 1-2mA normally, so if you have enough items on a circuit it can be prone to such trips.

A good electrician should be able to verify the RCD and you cable, etc, is working correctly. That is the first step in doing any sort of corrective work.

If that checks out OK, then some can also do PAT testing of appliances to see if any are unusually leaky. If so you might decide to replace it.

But the other option that would normally be suggested on here would be to put the washing machine and related appliances on a separate RCD, so hopefully the total that is worrying close to the 15-30mA trip range is then split in two, and both are below the trip point.

How easy and cost-effective that is would depend on your CU, if it has the space and if it is recent enough that new compatible parts are still available.
[automerge]1598980551[/automerge]
Can you post a photo of your CU?

If it has any personal information on it then please blank that out, but what is of interest is the view of the MCB/RCD, not any labels.
[automerge]1598980881[/automerge]
I can't find the clear explanation I saw before, but this explains a bit about RCD:

How do RCDs and GFIs work?

How circuit breakers switch off dangerous electric currents and save your life.

www.explainthatstuff.com

Probably others will have a better site to link to.
[automerge]1598981695[/automerge]
Another point is many appliances are left powered on at the mains but in stand-by, in these cases they often have as much leakage as when fully operating. So if you are in an unfortunate position of total leakage close to RCD trip and can't afford to make the sort of changes needed to fully fix things to be reliable, you would have to actually turn the unused appliances off at the mains socket.

Obviously not things like the fridge though that need to be left on!

Hi, many thanks for the informative post.
I unplugged almost everything on the circuit with breaker that actually trips and I ran the machine and it completed with no trips. Of course, this doesn't really prove anything since the machine has completed successfully when everything has been plugged in (hence the intermittent nature of the tripping).

It really sounds as if the best thing to do is to forget about going back to Bosch and to get an electrician to look at it instead.

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:

 

[Pretty Mouth]

When the breaker trips, does the RCD (between E and 1) also trip?

 

[GreenGoblin]

When the breaker trips, does the RCD (between E and 1) also trip?

I think it does. I have to pull it down (the red lever) and flick it back up again to get the power back.

 

[Pretty Mouth]

I think it does. I have to pull it down (the red lever) and flick it back up again to get the power back.

Yeah, it does then.

Please confirm: when the tripping occurs, if you leave the tripped breaker B in the off position, and reset the RCD as you have just described, the power returns to the washing machine?

 

[GreenGoblin]

Yeah, it does then.

Please confirm: when the tripping occurs, if you leave the tripped breaker B in the off position, and reset the RCD as you have just described, the power returns to the washing machine?

I've never tried that before. I can try it the next time it trips and report back. I'll be using the machine again tomorrow, so if it trips, I will reset the RCD while leaving the tripped breaker off and I'll see what happens.

 

[Pretty Mouth]

I've never tried that before. I can try it the next time it trips and report back. I'll be using the machine again tomorrow, so if it trips, I will reset the RCD while leaving the tripped breaker off and I'll see what happens.

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

 

[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..