Bosch Washing Machine trips fuse

[Rad1o]

We have a WAE28465GB which has been fine until today.
It went part way through the cycle and the fuse went.
It trips the RCD as soon as it is plugged in even when on the dial it is in the off position.
I opened the top and back but apart from black carbon deposits I cannot find any obvious fault.
It is not the socket - other appliances are working from it. And the washing also trips the fuse when plugged in elsewhere.

Does anyone know what it could be????

 

[PrenticeBoyofDerry]

RCDs are sensitive to earth leakage, they will trip if you have had water ingress into the electrical parts of the appliance and if something like the heating element is starting to fail.
Also worth checking for damage to flex and plug of appliance.
Do you have any socket outlets that are not protected by RCD?

 

[lavo-1]

It could be any high ampere component in the machine. If you have any idea on electrics then you may own a multi meter, but if you don't then it's time to call a technician and get it checked!
I cant hand out advise if you are not experienced enough to safely work on electrics, no disrespect to your abilities, but one incorrect test and its game over!
It could be anything from the mains filter shorted, heater element IR low or your motor IR low plus anything in between!
You really need a descent knowledge of electrics or a technician.

 

[bernardgreen]

opened the top and back but apart from black carbon deposits

the black carbon deposits are is probably carbon dust from the brushes in the motor. This dust is electrically conductive and often creates a short circuit between the brushes ( which are Live ) and the metal frame of the motor causing an Earth laekage which trips the RCD

It could be any high ampere component in the machine.

It is tripping the RCD which trips on earth leakage and not the MCB which would trip on over current

 

[jj4091]

Wrong post

 

[lavo-1]

opened the top and back but apart from black carbon deposits

the black carbon deposits are is probably carbon dust from the brushes in the motor. This dust is electrically conductive and often creates a short circuit between the brushes ( which are Live ) and the metal frame of the motor causing an Earth laekage which trips the RCD

It could be any high ampere component in the machine.

It is tripping the RCD which trips on earth leakage and not the MCB which would trip on over current

Exactly! Any high ampere component could be leaking to earth......where did it say over current?
Carbon brushes on that model do wear down, but the motor will stop turning before any damage to the motor. Once the brushes get too small they are designed to stop conducting and prevent any electrical damage on the armature.
It's hard to diagnose a tripping fault with out an Insulation tester or Multimeter.
If you want you could isolate the machine, remove the back panel and disconnect the plug/jack on the motor (its got a keyed plug so you cant put it back on incorrectly).
Then you can put power back to the machine and see if it will switch on without the RCD tripping.
Please MAKE SURE APPLIANCE IS ISOLATED FROM THE MAINS BEFORE YOU WORK ON IT!

 

[bernardgreen]

Exactly! Any high ampere component could be leaking to earth.

Your wording

It could be any high ampere component in the machine.

implies only high ampere components are suspect which could easily lead one to ignore low and zero ampere components.

It trips the RCD as soon as it is plugged in even when on the dial it is in the off position.

With the dial in the OFF position there are no components that are in a "high ampere" condition.

Most probably there is a Neutral to Earth fault ( neutral not disconnected when the dial is set to OFF ) through the carbon dust around the motor. But it could be any component or even a damaged wire trapped between metal parts

 

[lavo-1]

You are correct in assuming that a Neutral path is maintained through the appliance, but my experience with that model is that the carbon around the motor will not be the problem as the drive belt creates a lot of dust around the motor also.
I have changed many mains filters with IR faults on BSH appliances over the years and that would be my first point to check, but from there you will need some test equipment to safely diagnose the fault.

 

[Rad1o]

Thanks for the replies.
I asked the question because I do not have a construction diagram of our machine. I am happy to look at electrical items with multimeters and have been in fuse boards to know RCDs.
Anyway because I did not have too much to go by yesterday evening I managed to get an engineer to come today.
It was a heavily scaled heater element.
All working now.