Smug SUK91 oven instantly trips circuit breaker

[monkeyfinger]

Hi - we have the above Smeg oven. Whilst heating up last night, it turned off and tripped the circuit breaker. It now cannot be switched back on (and I mean just the switch at wall, no heating elements are on). It immediately trips the main circuit breaker for the oven circuit.

In the past I have replaced many fan heating elements, but this appears to be a different problem.

Any ideas on an area to look at, or is best route to get approved service involved?

 

[Jackrae]

Assuming by circuit breaker you mean RCBO etc, I suggest you check the neutral and earth connections - sounds like they may be contacting each other somewhere.

If however it's a simple overload device then sounds like you have a line to neutral problem.

 

[monkeyfinger]

Thanks for the reply. Although it is the RCD on the main house board that is tripping, I am sure that there is also a bang coming from the oven somewhere when I switch the power back on. Is it likely that the faults you suggest would occur when nothing has been disturbed on the oven wiring since the original install probably 7 or 8 years ago? I can't even remember the last time we pulled it away from the wall to clean behind, so that wire has not been moved. All that is normally powered up when the oven is switched on is the timer and maybe hob ignition circuit (I assume?), so I thought maybe a failure in those circuits.

But then if I knew this I wouldn't be posting on here, so all suggestions welcome...

 

[EightyTwo]

Remember that an RCD measures the electricity going up the live and back down the neutral. If there is a difference, it trips. A difference can be cause by live-to-earth (when you're being electrocuted) OR EARTH-TO-NEUTRAL.

It's possible that an element has blown and the neutral end has shorted to the outer cover which is earthed. Alternatively, the inner insulation could have failed and the element is shorting to earth. (like Jackrae said).

I'm not an appliance specialist but I'd be inclined to pull the oven out and disconnect elements one at a time until I could get the RCD to stay on. That should indicate the dodgy one. Then discconnect both ends and check it with a multimeter.