Circuit breaker basics

[Calculus]

The washing machine (AEG 8000) has gone rogue. Iţ trips the electrics either immediately or within seconds. I have drained it and left it to dry for a few days but to no avail (except to give me a few more seconds before the trip). It is over 5 years old so replacement is probably better than repair, but I want to be certain it is the machine itself causing the problems and not a fault with the house electrics. These are the tests I have done:

1. Run a 2KW heater from the same socket with no tripping. This would seem to exonerate the socket.
2. Tried to run the washing machine from a different ring circuit (i.e. a different one of the four MCBs in picture). The electrics are tripped just the same.
3. Examined the power cable. Looks intact, as does the sealed plug.

So it seems obvious the washing machine is the culprit but there's one thing that gives me doubt. When the trip occurs the main circuit breaker (grey box between the 4 MCBs and the 2 lighting MCSs) switches off but the individual MCBs always remain on. Is this significant?

 

[Murdochcat]

The "grey" box is an RCD which detects leakage to earth and isolates ALL the circuits downstream of the device

From what you've written is does sound like your washing machine is faulty.How old is it?

And maybe get an updated CU fitted with RCBO's so that a single fault doesn't have such a negative effect.

 

[Calculus]

The "grey" box is an RCD which detects leakage to earth and isolates ALL the circuits downstream of the device

From what you've written is does sound like your washing machine is faulty.How old is it?

And maybe get an updated CU fitted with RCBO's so that a single fault doesn't have such a negative effect.

The washing machine was bought January 2020 so is about 5 and a half years old. It cost about £850 I think. I have no idea how to go about fitting an updated CU.

 

[Calculus]

....but going back to the initial question, is it normal for the main circuit breaker to trip but the MCBs to remain untripped?

 

[pete01]

Yes completely normal an mcb would trip on overload or a short circuit, an rcd trips with earth leakage.

It can also happen the other way if the circuit was overloaded the mcb would trip and the rcd wouldn't.

You can also get rcbos which are a combination of the two.

 

[Taylortwocities]

. I have no idea how to go about fitting an updated CU.

simple, you find a registered and competent electrician and say “I need a new consumer unit with RCBOs”

It is not a DIY job!

 

[Calculus]

simple, you find a registered and competent electrician and say “I need a new consumer unit with RCBOs”

It is not a DIY job!

I feared as much. Electricity is as terrifying as water

 

[Jurassicspark]

The washing machine was bought January 2020 so is about 5 and a half years old. It cost about £850 I think. I have no idea how to go about fitting an updated CU.

Regarding the RCD tripping, its probably the heating element but you mention it trips instantly so probably not. You can rule this out by running the machine on a cold wash. It can also be carbon dust in the motor, does the motor ever spin?

 

[Calculus]

Regarding the RCD tripping, its probably the heating element but you mention it trips instantly so probably not. You can rule this out by running the machine on a cold wash. It can also be carbon dust in the motor, does the motor ever spin?

It doesn't remained untripped long enough to do any realistic testing. This morning, after having 2 or 3 days to dry out, I switched it on and it didn't trip. But when I opened the water valve to let it continue with its program it filled for maybe 30 seconds then tripped. After that, even after more draining, I wouldn't go more than a few seconds without tripping, even when I was doing nothing. I suspect there is an internal water leak but not sure at all.

 

[Taylortwocities]

It doesn't remained untripped long enough to do any realistic testing. This morning, after having 2 or 3 days to dry out, I switched it on and it didn't trip. But when I opened the water valve to let it continue with its program it filled for maybe 30 seconds then tripped. After that, even after more draining, I wouldn't go more than a few seconds without tripping, even when I was doing nothing. I suspect there is an internal water leak but not sure at all.

If there was a leak, you’d probably spot a puddle. Probably a component where water and electricity meet, like a pump, or valve.
Obv thd appliance. Either get a repair man in, or replace it.

 

[Calculus]

If there was a leak, you’d probably spot a puddle. Probably a component where water and electricity meet, like a pump, or valve.
Obv thd appliance. Either get a repair man in, or replace it.

When I was draining it there did appear to be puddles nowhere near the draining spout.

 

[CountryFan]

At £850 surely a repair is better?

 

[ericmark]

These are the testers we use, and they are not cheap, I paid £35, £35 and £75 for my testers, and it also needs skill to use them. But anyone would help sort out what is faulty.

 

[Harry Bloomfield]

It doesn't remained untripped long enough to do any realistic testing. This morning, after having 2 or 3 days to dry out, I switched it on and it didn't trip. But when I opened the water valve to let it continue with its program it filled for maybe 30 seconds then tripped. After that, even after more draining, I wouldn't go more than a few seconds without tripping, even when I was doing nothing. I suspect there is an internal water leak but not sure at all.

It is the RCD which is tripping, which offers protection to most/all of the circuits in your house. If any circuit develops leakage to earth, possibly via you, or a member of your family, or perhaps via water where it should not be - then it will trip.

If your washing machine is leaking water, that could well be all it needs, to cause the RCD to trip. Your most recent post, seems to be suggesting your machine does maybe have a leak. If so, then fix the leak, rather than the symptom.

 

[FrodoOne]

simple, you find a registered and competent electrician and say “I need a new consumer unit with RCBOs”

It is not a DIY job!

I completely agree with the above.

Hopefully, you will not need to have the "Supply" connections and the Meter changed/moved - at your expense.

A new Consumer Unit is required,
with RCBOs for all circuits.

(Even the existing "Extra Low Voltage" "Bell Wiring" is poorly done - and should be done better.)


Since it seems unlikely that a new CU would fit in the existing (high) location,
it is to be hoped that sufficient space is available below the Supply connections and Meter etc.