Oven intermittently tripping the power.. when it's turned OFF

JMFD

I've seen lots of advice for people with ovens tripping the fuse when turned on, but I've got a bizzare situation where turning the oven off intermittently trips the power. Usually more likely to occur if the oven has been on for longer.

Any ideas before I get a sparky in?

coffeehound

What kind of control does it use to switch the oven off,, e.g. is it digital or old-style rotary knob? Or is it when you switch off at the wall switch?

JMFD

Old style turning knob, and it's when the knob's twisted off (rotating in either direction to the "off" position), it trips.

Jonesya

What exactly is it tripping?

RCDs and RCBOs can be tripped by neutral-to-earth faults, which *could* occur even when the device was switched off, if it used single-pole switching.

JMFD

The circuit it's on flips to off at the fuse box, it's fine being immediately turned back on.

Jonesya

And what's the device in the fuse box that's tripping - is it marked 'MCB', or 'RCD' or 'RCBO'?

JMFD

I can see RCCB on the test button next to the switch, but none of the other acronyms

Jonesya

It's not something you can diagnose over the internet - but if it's tripping as soon as you switch it off, I'd be looking at the switch itself at first, and then the heating element.

Geoff1963

My parents had this on a table-top food heater, first time they used it after having the house wiring uprated to RCD.
RCD = Residual Current Detector
RCCB = Residual Current Circuit Breaker
They are the same thing, detecting a tiny current is somehow leaking to earth.

Sounds as if the oven needs fixing, although it might just be the switch. The "being on longer" might be because the elements are hotter ; but it is odd that ( unlike my parents' heater ) it isn't a continuous tripping effect.

EachPenny

If it is the control for the oven (not for the rings) then it would also be a thermostatic control and should turn the heating element on and off when the oven is at operating temperature.

Does it ever trip out when the oven is hot and the thermostat is switching on and off, or is it only when you return the control knob to off?

DIY repairs to kitchen appliances are not a good idea so you'd need to get someone in to fix it. But having some idea of what the problem is and the age of the oven will affect the decision whether to pay for a repair or just get a new oven.

JMFD

Thanks all, it only ever trips when turning off, and I have a separate hob.

I've asked the local appliance repair place to look it it before, buy thumbs not showed up I'll try again.