Combi Oven tripping MCB....when fan assited oven has run for 15 to 20 mins!!??

marconi · Dec 6, 2020

It would be very helpful to know how the ring circuit at your friend/relative's is supplied ie: RCBO, MCB, MCB and 'up front' RCD or a fuse. If it is easier take a photo and post it.

Also when you do the everything unplugged test I should have asked you to turn off all switched fused units which look like these and may also be fed off the ring:

https://www.tlc-direct.co.uk/Produc...nqwRxNmRuh7n7RMb9Ym4WGQBjxfaInNxoCJaYQAvD_BwE

Sparkingmad · Dec 6, 2020

Is the element in the oven loose? Has it moved backwards? Stoves used to have an issue where due to bad design the oven element could slide back when element heated up it would expand and cause the connections on the back to short on the back casing. Also they had aluminium foil on the insulation on the back of the oven. This one had me going for ages, stripped the damn apart and tested all fine put back together shorted out. In the end I had insulation resistance test the damn thing after every screw was put in. Finally found that the foil was deflecting and touching a neutral connection on the back. Good luck.

Sparkingmad · Dec 12, 2020

Tonewheelkev said:
We appear to be on a similar wavelength here!
Funnily enough....my next move was to take the unit to another dwelling....to see if I can replicate the trip.
It also occurred that I might borrow a 2kw bar heater...and see if that also brings along the trip.
Perhaps...there's a problem with the Wylex breaker!!
As it happened....ran autoclean yesterday FWIW......can't find any info 'out there' ....on how important (or otherwise!) it is to run this.
Had the unit apart today.....it's soooo clean really....can confirm no cooking incidents.
If the unit does work 'elsewhere' without problems...I'll look into having the breaker tested/exchanged
Sounds like a plan!!

How did you get on?

Mike Johnson · Dec 12, 2020

I saw an interesting video on u-tube on this subject, seems the oven heating element had a split in it and it took about twenty mins for the trip to happen due to expansion of the casing.