Induction hob trips RCD

[reg091]

Depends on the electronics package... Neff ones pre soak the induction coils via the TRANSFORMER ( clue there), cheaper ones tend to use capacity charging and both would give a fair amount of leakage when you apply power, neff have a builtin out saying they expect 6-8mA as it cycles on .. why do you think induction hobs take min of 30 seconds to warm up before use ? One wonders what they are doing ??

As I said the quickest way is to flip off all the other circuits and just flip only the induction hob on...especially if the call out is one of those dog sh!te ones that charge if no fault is found with their kit.

Thanks. I'll try the other circuits off and see - good thinking.
Hob is Beko, callout is Electrolux (presumably own Beko), and yes, £55 if no fault with the hob. Fair enough.

 

[reg091]

UPDATE: Engineer couldn't find a fault with hob initially. Spoke to his office who had him separate the two lives and two neutrals (option for three phase installation I think). Testing then showed some fault. Replacement coming.

 

[reg091]

UPDATE: After a lot of hassle getting the replacement hob (don't talk to me about Hotpoint "customer service") it eventually arrived and was fitted by them. Same result, instantly trips RCD....

Tried it with all power breakers except the cooker circuit off and it works fine. Turned breakers back on one by one until it tripped. Was going to investigate that circuit until I realised that it was random: sometimes the circuit that I thought might be the culprit worked fine when I switched the breaker on, and other breakers that had been fine also tripped the RCD when turned on. (All this testing in the space of a few minutes, so nothing plugged/unplugged on any of the circuits).

My plan then was to put the cooker circuit in a separate CU with it's own RCD, but first I took a punt and replaced the RCD....

Problem solved, faulty RCD! How Hotpoint found a fault with the first hob is a bit worrying!

 

[ericmark]

It is a problem, had it myself, the tests show RCD is OK, and back-ground leakage OK, but renew the RCD and fault vanishes.

 

[martygturner]

yep easily the issue, new hobs chuck out a fair bit of leakage, and current testing is all on the will fail at one times mA but of course it can fail much earlier at lower mA and still pass the 1x test.

 

[ericmark]

I can easily test total mA leakage,⁣ but

to test each RCBO requires covers removing from the CU, and I can test each RCBO feeding a socket, but again those not feeding a socket, need more work to access to test.

As to if worth it, well I would only bother if I have a problem, and as shown the RCBO on ramp test trips at 21 mA and it passes at not tripping with 15 mA so one can have RCD's which can allow 14 more mA to an identically rated RCD, and the spike needs to be less than 40 mS so unlikely to show up on any meter, unless using an oscilloscope, so sometimes only option is the change the RCD.

 

[endecotp]

RCBOs have their advantages.