ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades UK cooker/RCD problem

I have an old but virtually unused AEG cooker. When a ring or oven/grill is switched on the RCD trips after about half a minute. Even if the ring is turned off it will not then reset. After a couple of hours however the cooker works for 30 seconds, then trips off. Checks with a multimeter reveal no obvious anomalies.

Is this a common problem? Can it be fixed?

Sounds like an element fault, probably registering through the neutral to the elements. Multi-meter as useful as a chocolate tea pot. You need insulation tester to show fault up. Sounds like a job for an electrician not recomended for the DIY.

Can also be insulation failure elsewhere in the cooker, or even in the wiring to the cooker, triggered by a temperature rise... ...I'd stop using this cooker!

As it's not just one ring causing the trip, I'm doubting an element fault.

Edit: Duh, you can only use it for 30 secs anyway!


[This message has been edited by gideonr (edited 09-15-2005).]

An interesting problem this.
In NZ and Australia the wiring regs exempt cookers and ranges from requiring RCD protection, and I have always assumed that the reasoning for this is that cooker elements have a naturally high earth leakage current. This makes some sense, as elements constructed with a conductive core and sheath separated by mineral insulation which seems like a good recipe for high leakage.
Can agaricus bisporus advise us is the RCD required by code? If not, then the best bet may well be to remove it.

Thanks for the replies everyone.
Can't see it as a result of thermal changes in the general fabric of the cooker as it seems to happen within the same timespan regardless of whatever unit is energised.

No regs require an RCD, just seems prudent - and no, I'm not a professional electrician and I won't risk aq dodgy cooker if the RCD says it doesn't like it. Sad thing is my gut feeling is there's nothing wrong with the cooker and the RCD is being overly sensitive. Don't want to trash a good cooker for that reason.

Additionally I now use on the same circuit, a Baby Belling that used to fire the RCD in my parent's house but works as good as gold next to this damn AEG cooker...

Ain't no continuity here..!

AB this is why you need a sparky! He will have all the right equipment to test both the RcD and the cooker. Very sensible not to remove the RCD until you have proof that its faulty. Please! get them checked out.

A good sparky should have a nice big tester that can tell if your cooker is faulty or your wiring and besides can measure and draw up a graphic trip curve of your RCD.

I'm with the majority here,
It could be to do with moisture, but you really don't know.
A-B, take our advice and get a good Electrician.
Best of luck, mate!.

Yep, it's hard to really be any more specific without testing.

I'd have my megger (high-voltage insulation tester) on the stove to check for leakage, then with the back removed isolate each section in turn and test again to localize the problem.

While an RCD isn't required by the regs, a 30mA RCD shouldn't really trip with a modern cooker.

I would be particularly concerned if the element tripping the RCD is a halogen / burried in a ceramic hob.

It's well worth getting it professionally checked out.