Main fuse blowing - washing machine?

[Lorenzo]

The fuse (in the fuse box) keeps blowing every time I turn on the washing machine. I have tried plugging it in to other sockets and the same thing happens. I guess this must be an electrical fault with the machine, but surely that would have blown the fuse in the plug, not just the box? Any thoughts?

[Palindrome]

Did it blow when plugged in - with the machine switched off at the machine?

If yes: it just could be a fault in the moulded plug. Unlikely, but I have carved one open to find the (bare) neutral wire running very close to the live plug pin (which wouldn't have sent any fault current through the plugtop fuse, if it did touch).

Is it a fuse in the box or an mcb? If a fuse, are you wiring it with the right fuse wire? If an mcb, it may have gone faulty and be tripping on too low a current. If you are plugging it into another socket on the same ring, then you will be using the same protective device. Does the fuse/mcb blow/trip when you plug in and run a 3kW fan heater?

When you say the fuse blows, do you mean the earth leakage breaker? If you don't have one protecting the sockets, I'd put that right anyway..

However, the more likely problem is that there is a fault in the machine. If it is an mcb tripping, then the fault could be an overload that trips the breaker but doesn't have the right i2t profile to blow the plugtop fuse in the time that the breaker trips.

So, I would try plugging in a fan heater. If that trips the breaker - the breaker probably needs replacing (assuming that nothing else is plugged in and running on the ring). If it blows the fuse, you are using the wrong fuse wire.

If it trips/blows with the machine switched off at the front panel, I'd check the cable for damage and chop the plug off and fit a new one.

Otherwise, depending on the age/value of the machine - you need to repair it/get it repaired or replace it..

[Lorenzo]

Thanks for all that.

Blows only when I switch machine on.

I checked plug at beginning and everything looked fine.

Sorry here comes the ignorant part. It triggers the switch on the thing I have always called the fuse box. This can be reset by pushing the switch back into place.

I can now see that I should have tested it on another circuit too. I just moved things around on the same circuit!

I think it is probably the machine too, I was just looking for confirmation and an explanation of why the fuse didn't blow. Any fault/overload coming from the machine and reaching the fuse box must surely must pass through the fuse in the plug? That makes no sense to me.

The machine is old (relatively!) and we were intending to upgrade it anyway some time ago. We have therefore ordered new, bigger, quicker and more energy efficient one.

When that is plugged in, I might well be posting back to say "Help, it wasn't the machine after all!"

Thanks again for all the advice.

L.

[ARWadsworth]

Is it a main switch with the letters RCD or RCCB on it that trips? If so you have a neutral earth or live earth fault on the washing machine that would ot blow a fuse or trip a MCB but will trip a RCD.

Adam

[Lorenzo]

Yes, it says RCCB on it. There are several batches of switches in different areas, so I find it pretty confusing.

Thanks for the advice!

[ARWadsworth]

Then the washer is knackered and your electrics are fine.

Adam

[Graham]

Then there is leakage to earth within the machine. It may be very slight, and before RCDs RCCDs and ELCBs were the norm your machine would have continued to work and you would be unaware of any problem.

When the same thing happened to my machine about six months ago. The problem was some carbon deposit on the outside of one of the the plastic brush-carriers, causing leakage to the frame of the motor. Cost of DIY repair zero. (That's if you don't count the rip in the floor vinyl I made when pushing the machine back)

[ARWadsworth]

Cost of DIY repair zero.

(That's if you don't count the rip in

SWMBO will make you pay forever.

Adam