I recently bought a 2nd hand cooker. It's a Flavel Milano E60 ML61CDS. It is an induction hob cooker with a separate grill & oven. It's on an RCD in the fusebox (80A 30mA) The hobs work fine and don't cause any issues. Both the grill and oven will trip the RCD however they don't trip it straight away. They only trip once they are warm. The oven bizarrely will start fine from cold but trip when you turn off the knob powering it. Oven lights and fans work fine.
My old cooker didn't have any issues with the RCD, so I don't think that it's a problem. I was thinking of changing the elements but 2 simultaneous element failures seems unlikely. Any ideas what to look into?
As it trips the RCD when it gets hot, I would suspect it is the elements. You could try safely isolating each element in turn to establish which one is causing the problem, but it may be each on its own is not enough to trip the RCD. As you purchased it 2nd hand you now know why it was sold. It could also be that where it came from did not have any RCD protection.
An oven element is mineral insulated, and the mineral is hydrophilic that is it has a special affinity for water. So there are seals on the ends to stop water getting in, if the element is used on a regular basis even if it does allow a little in, it will drive it out again, but if left unused too much can enter.
There is a second problem, most controls only work on the line, and the neutral stays connected, but since with no load neutral is same voltage as earth, but when there is a load then current can flow neutral to earth, so a fault on one element can cause it to trip when other one is used.
Also the more circuits are put on one RCD the more likely it is to trip.
So the oven may have worked in the original house. Yet failed in your house. The tool we use is a insulation resistor tester that uses 500 volt, so what you need to do is decide is it worth just getting new elements, or would it be better to test first. I think I paid £35 for the last insulation tester I bought.
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