AEG Oven 49176V-MN, Tripping Main Board RCD but not Cooker Circuit RCD

[brightspark]

Hi people,

I’ve got an AEG cooker with the double ovens and ceramic hob (not induction). The cooker had previously very occasionally tripped the main RCD when the top oven grill was switched on, but didn’t trip it if the top oven function was switched on.
Just today using either oven at all now trips the main RCD as soon as they are selected “on”.
Using the hob didn’t seem to ever cause a problem before today, but today, switching a ring on for a while (10 mins) does now seem to cause the main RCD to trip.
Switching on power to the cooker after resetting the main RCD doesn’t trip the main RCD.
The cooker circuit RCD doesn’t trip, just the main RCD.
I disconnected power to the oven switch, cleaned the back and sides of the cooker (it was pretty grimy), cleaned, dried and checked and tightened all the power cable connections (none needed much if any tightening), cleaned the oven power cable.
Still got same problem with tripping – is this more likely to be a problem with the cooker or with the house wiring?
It’s an oldish rented house and the wiring is not very up to date but has been checked occasionally (most recently 2022) and had some sockets replaced etc. It did have the earthing upgraded a few years ago which made everything much more reliable, as did work on the supply side which used to be very flakey going off every few weeks but is now much better.
I’ve got basic electrical knowledge and respect, and a multimeter, is it worth me trying to trace an earthing problem?
Any ideas?

[electrofix]

well most likely fault is always an element

turn off at the cooker switch, make sure oven is dead, remove back, set muiltimeter on a high ohms scale 2M or above
then disconnect each element in turn ( all wires) then place one meter probe on one of the element terminals and the other on the oven metal chassis

you should not really get any reading but if you do anything under 10M is suspect

Dave

[brightspark]

Cheers thanks for that Dave,

I’ll have a go in the morning.

[brightspark]

Does anyone happen to know the size of the hex bolt heads which retain the grill elements? They look very small so I’ll need to get another micro bit set.

[electrofix]

you dont need to take the elements out to test them just remove the back of the oven and access from there

Dave

[andyjawa]

Does anyone happen to know the size of the hex bolt heads which retain the grill elements? They look very small so I’ll need to get another micro bit set.
nuts are 7mm from memory.

[brightspark]

OK, bit of a delay to get over worst of the flue or whatever.
RCD “fuse” for cooker circuit off, tested for power to cooker, then once back off, tested again. Had back off and tested all the elements in situ for earth. Didn’t find any earth issues but did find that the top oven bottom element was open circuit – is it possible this is causing all the issues?

[electrofix]

possibly

try disconnecting all the wires to that element. make sure they are well insulated and away from any heat source etc

Then try it and see if it trips

Dave

[brightspark]

Yep, thanks Dave, disconnecting the top oven-bottom element seems to do the trick. Don’t really get why an open circuit heating element should cause all the other problems, but maybe that’s another example of the effects of cost cutting. I’ll just replace and keep fingers crossed.
Any suggestions for how to remove the top oven-bottom element? Do I need to go in from the back and remove all the insulation to get it out?
Is there any point getting a “genuine” replacement element?

[electrofix]

i always fit gen parts as the copy ones dont seem to be as good these days. Plus this element is not that dear

https://shop.aeg.co.uk/?gclsrc=aw.ds&gad_source=1&gclid=EAIaIQobChMImYnb59rIgwMVF5ZQBh3p9A3KEAAYASAAEgKvJvD_BwE&gclsrc=aw.ds

go here and enter the model and PNC number of your unit. you can then select the part

looks like is about £27

Dave

[Author]

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