SMEG A42 tripping main house breaker when at temperature

[Seccy]

I have a SMEG A42 (the orginal one I think as it only says A42 on the data plate).

After the main fan oven has been at temperature for about 10 minutes the main house breaker trips. The 32A cooker circuit has never tripped so I suspect a neutral fault. I have replace the fan element but this hasn’t rectified the fault.

I tested the oven temperature last night and found (using a thermocouple mounted in the center of the oven) that when the thermostat was set to 150C the oven was at 180C (at least oscillating about this temperature as the controller cut in and out) and at 200C it was actually 240C. Strangely this time the oven was on for over 1hour without causing a fault trip! I don’t know if these temperatures are typical of the error in oven thermostats or if these are excessively high. We rarely have the thermostat set to over 200C.

I intend to Megger the wiring this weekend and wanted to confirm what the maximum voltage I should test at to insure I didn’t blow any of the circuitry.

Is there anything else I should look for or is there any obvious faults which would cause my problems?

Thanks in advance.

[digger27]

Re: SMEG A42 tripping main house breaker when at temperature

I also have a Smeg appliance (an A1-5 range cooker) where the electric oven is tripping out the main RCD breaker for the house after it has been on for a few minutes. I’ve also replaced the fan element but the fault remains. Have you had any luck in tracing the cause of your own RCD problem?

[Seccy]

Re: SMEG A42 tripping main house breaker when at temperature

I’ve just replaced the thermostat – no help. I am now swapping common components with the top oven – there is a gray potted box with two blue leads and two white leads (I think it is is suppressor) I swapped this over but it made no difference, I have also disconnected the rotissary motor. The last change I made was to swap over what I think is the overtemperature thermostat (blue box with a symbol of two switches). I’ve only run the oven once since doing that and it didn’t trip….but that doesn’t mean much as it sometimes works. I am however running out of components to change.

The only things I haven’t completely ruled out are: the two fans and maybe the grill element (even though it isn’t on when the fan oven is running).

Let me know if you find anything.

[goosegreen]

Re: SMEG A42 tripping main house breaker when at temperature

Have found 2 main oven fan motors to go down to earth when hot on A2As, Might worth checking with your megger.

Goose

[Seccy]

Re: SMEG A42 tripping main house breaker when at temperature

Looks like it was the oven fan motor. It has been over a weeks since I replaced it and everything seems fine now. 😀

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