Neff oven fault

[elmsoft]

A friend has asked me about a fault on her ( 20 year old ) Neff Oven.
It switches on OK and then after about 60 seconds or so it trips the rcd at the consumer unit.
The odd thing ( to me anyway) is how consistent the time is. It always switches on and always trips after a very short period of heating.
Does this symptom point to any particular line of investigation? Is that, for example, how oven elements fail?

 

[jamesmcbride]

You'll probably be best doing an insulation resistance test on the elements.

I would guess ( I don't know about this oven specifically) that it doesn't actually apply power to the element immediately, hence you're seeing the delay

 

[elmsoft]

So it sounds as if the elements are faulty.
Maybe just renewing the elements would be best practice?

 

[bernardgreen]

Neff are very good but 20 years is a long life for even a Neff oven. Some will last longer.

If it is a Circo therm where the fan blows air over a circular element behind the back wall of the oven and the circular element has failed then check the fan is rotating freely. If the fan is running slow the element over heats,

 

[EFLImpudence]

How can an element overheat?

Surely the fan is to move the heated air, not to cool the element.

 

[slup]

I suppose if the thermostat is elsewhere in the oven cavity, and the fan isn't running, the element itself could get hotter and hotter - possibly beyond it's design parameters?

It's not that the fan is there to cool the element, but it is certainly there to move the heat from within the little fan/element compartment and into the main part of the oven.