Oven Randomly Trips Main Breaker

[EQp]

I've just had a new kitchen built, which includes an oven that I used in a previous kitchen.

Whenever I use the oven, it randomly trips the main 50 amp breaker. It doesn't matter if nothing else in the house in on, or if I turn on all the ac and water heaters also.

Never does the RCD or kitchen breaker trip.

I've had a look behind the oven, the Thai sparkies have done the usual wiring with electrical tape. However, good news is there does seem to be a ground wire.

I guess the first thing is to wire it up correctly. Whats the way to join wires in Thailand? Wire nuts? But I am still at a loss why it trips the main 50 amp breaker and not the 15 or 20 amp kitchen breaker.

[Jdietz]

Maybe the "electricians" bypassed the kitchen breaker and hooked it up directly to the main breaker. Be careful to switch -everything- off and then still test before disconnecting anything, as I have seen them even bypass the main breaker on a shower install. (though in your case the main breaker definitely is connected)

Check for wires prodding out of the tape contacting occasionally with the metal frame of the oven, that'll do it.

Get a decent screw connector block and a plastic box to mount it in, screw box to wall and mount it up properly.

[Crossy]

Agreed ^^^. Carefully check everything, particularly where it's fed from.

Does the main breaker incorporate earth leakage protection (does it have a 'test' button)? Ovens that haven't been used for a while can go leaky, they tend to recover after a few uses have dried out the works.

To open a 50A MCB on over current alone is a pretty serious fault for a 3kW oven.