One for the theorist amongst you...........................

[R G]

At the end of the day the answer has to be a clamp meter on the CPCs at the D/B with appliances connected,
in use and removed .

 

[ImpededLoop]

Is the upstairs lighting circuit on the same RCD as the kitchen ring final circuit?

Is the microwave socket on the kitchen ring final, or it's own circuit?

Apologies if this is in the OP and I've missed it.

 

[Guest111]

At the end of the day the answer has to be a clamp meter on the CPCs at the D/B with appliances connected,
in use and removed .

you need to clamp the tails,clamping the cpc's won't tell you anything,think metal backboxes screwed to brick walls.not all the leakage comes back down the earth.

 

[tazz]

Quick question...is the microwave ontop of another appliance such as a fridge, or on a stainless steel worktop..?

 

[SirKit Breaker]

Quick question...is the microwave ontop of another appliance such as a fridge, or on a stainless steel worktop..?

No its on a wood worktop and nothing else near it

 

[SirKit Breaker]

Have you clamped the tails? I would venture to suggest that the "backgroun" leakage is high and the microwave simply tips the RCD "over".

Murdoch, but why only on one socket..........or i am i being thick and missing something!

 

[SirKit Breaker]

I had a similar problem once on an old microwave and even though testing the MW proved o/k , when in use it did trip the RCD , If this mate has just moved in with this MW , I would have thought any issue with wiring faults would have been sorted by previous owner , as they would have had a MW and the installation is new .

they are the first occupier after the renovation. I appreciate the comments about an old microwave, but why does it only trip on one socket, and work ok on all the others. If it leaks into one socket, it leaks into all of them, and should trip the RCD on any socket not just this one!

 

[R G]

Another thought , could you carry out a ramp test at that particular socket , see what that shows , compare the readings with everything plugged in and without ...

 

[telectrix]

me clutching at straws but tthere could be a high resistance connection, maybe art another socket. try a R1+R2 and a Rn+R2 test and see if there's any appreciable differences between sockets and/or between the L-E and N-E.

 

[ImpededLoop]

Is the upstairs lighting circuit on the same RCD as the kitchen ring final circuit?

Is the microwave socket on the kitchen ring final, or it's own circuit?

Apologies if this is in the OP and I've missed it.

Could you confirm these please Howard?

 

[tony mc]

IR test the socket you took off to see if it is breaking down between either N / E or L / E and if it is the socket you put on might be the same worth a try !

 

[Darkwood]

Check the plug top pins for arcing dots/tracks if any exist then the heavy load of the microwave through a loose connection of the pin and socket receivers are arcing under load and rcd/rcbo do not like this, this would explain why your issue is local to only one point.

If confirmed then replace socket and plug top.

 

[ImpededLoop]

Out of interest, how close is the microwave to the consumer unit?

 

[ruston]

Check the plug top pins for arcing dots/tracks if any exist then the heavy load of the microwave through a loose connection of the pin and socket receivers are arcing under load and rcd/rcbo do not like this, this would explain why your issue is local to only one point.

If confirmed then replace socket and plug top.

He has replaced the socket , I am with you on the plug top being suspect though

 

[Darkwood]

After years in the business I'd of just done a few checks as he has done then replaced both plug and socket as routine not just the one... this tends to save a lot of return trips at the sake of a £1 item.