Help with a tripping washing machine

[Chris Archer]

Hi Guys,
I'm having trouble diagnosing a fault on a customers downstairs socket ring, which only ever trips when the washing machine is used.
The fuse board is an MEM Memera 2000
the downstairs ring is on a 32A 60898 MCB, protected by a 61008 RCD 100A 30mA
there are 2 other circuits on the same RCD which are the upstairs rings on a 32A 60898, and the shower also on a 32A 60898

The customer had this problem before I came and had already tried replacing the washing machine and getting the same problem.

• we have carried out fault finding and also EICR'd the whole house with perfect results,
• we have tried plugging in the washing machine upstairs which is the same RCD and it didn't trip. and also on another circuit in the garage on a different RCD which also didn't trip (both times the washing machine stayed in the same position in the kitchen under the worktop and was just plugged into different sockets via an extension lead
• we have also tightened all connections on the downstairs ring assuming that maybe the washing machine vibrating could have caused a loose connection and tried fault finding again and cant find any problems
• we have also tested for overload by unplugging every other thing on the circuit and it still trips
• we have also replaced both the RCD and the MCB and still it keeps tripping
• I have tried plugging into other sockets on the same circuit and it still trips
• I have also tried replacing the socket its plugged into just in case

Yet we cant find any fault so I'm absolutely stumped, is there anything I've forgotten to do?

Thank you in advance, I'm loosing hair over this problem haha

Test results for Downstairs socket ring
R1 0.57
RN 0.57
R2 0.95
R1+R2 0.38
Zs 0.63
RCD 1/2x didn't trip
RCD 1x 27.8ms

UPDATE
so I changed the faceplates and still it kept tripping,

Now I've switched the downstairs sockets with the 32A cooker circuit on a different RCD and now everything seems to be running smoothly,
So does this mean it is accumulative earth leakage across all 3 of the circuits (down sockets, up sockets & shower) on the tripping RCD that must have been causing my problem?
As the RCD is exactly the same as the one that was originally tripping

Cheers for all your help everyone!

 

[newfutile]

You need a sensitive clamp meter on the tails to test earth leakage current from all circuits , failing that a ramp test with all circuits connected may help trace this .

 

[nicebutdim]

UPDATE
so I changed the faceplates and still it kept tripping,

Now I've switched the downstairs sockets with the 32A cooker circuit on a different RCD and now everything seems to be running smoothly,
So does this mean it is accumulative earth leakage across all 3 of the circuits (down sockets, up sockets & shower) on the tripping RCD that must have been causing my problem?
As the RCD is exactly the same as the one that was originally tripping

Cheers for all your help everyone!

The isolator was always going to be an unlikely option and previous information seemed to have ruled out the possibility. If I can remember correctly the issue is limited to this one circuit and you had tried disconnecting all other loads on the circuit , which effectively rules out any cumulative effect (unless some load was overlooked).

I can't remember all previous information, but believe the washing machine had already been replaced. The post above is where you need to be, with ramp testing of RCD and determining leakage from appliance, circuit to which it is connected and all circuits connected to this particular RCD, although it didn't trip when machine was connected to another circuit protected by the same device.