Nuisance RCD trip.

[Bobble23]

Customer called me out today. Installation has been fine for years until they had a 24 hour power cut last week. Since then the cooker circuit constantly trips the RCD. Dual RCD Doepke board. TNCS.

I disconnected the cooker switch and it still tripped. Had a look inside the CU and no loose connections or anything obvious. End of the day so didn't have time to do an insulation test on the cabling.

Two questions:
i) Is it a coincidence that the problem turned up after the power cut?
ii) Any ideas what could be causing the tripping?

Any help gratefully received!

Thanks.

 

[Octopus]

How long would it take to do an IR test?

 

[Bobble23]

I know, but my dinner was ready! And I'm back there tomorrow anyway. Any any other excuse I can think of!

 

[oldtimer]

Yep don't take this the wrong way and if you do you should not be doing this job you say the cooker circuit trips the rcd but as Murdoch says have you done an IR test ? A lot of posts like this would not be on here if the poster did all the circuit tests.

This is not a correspondance so a bit of advice would be to do all the tests you can note the results down then come on and get advice.

 

[Bobble23]

Point taken Oldtimer. Will set off tomorrow with a renewed work ethic!

 

[Octopus]

Well, has it rained? rodents been chewing? DIY Dick with a hammer & nail?

 

[Sharpend]

Well if only most posters with Rcd problems would heed that advice then maybe just maybe there wouldn't be as many rcd posts, as any good tester will tell you that adhering to the tests as prescribed in the BGB will locate the fault.

 

[GLENNSPARK]

I know, but my dinner was ready! And I'm back there tomorrow anyway. Any any other excuse I can think of!

put off by the pie.......

 

[Knobhead]

I’ve heard it all now. Can’t do any testing, my dinners ready!

 

[diditrain]

Is the cooker the only circuit protected by this RCD. Could be a long day for you trying to find this fault and expensive for the customer.

 

[Sharpend]

It might be cheaper if you had dinner with the customer?

 

[Andy78]

It might be cheaper if you had dinner with the customer?

He can't. Cooker's not working. Probably why he went home for dinner yesterday.

 

[Sharpend]

Anyone for boiled rice!

 

[7029 dave]

do IR test, and also disconnect cooker switch and dead test into appliance and back to cu.

 

[oldtimer]

I was called out to the same fault last year found one of the elements was down to earth on the cooker so hold on you say the cooker switch is double pole so when you switch it off the RCD should reset . Well yep but if one of your poles on the cooker switch is welded together ie switching it off does not break the circuit.

Ended up the domestic appliance guy got a shock and was giving me thats Bl00dy dangerous speech when his boss came in and I replied that if you followed a safe isolation procedure you would not have got a shock he said I could have been killed and I replied yea but your insurance company would not have paid out due to your negligence then it went quite