Re: Microwave ovens
As others have already said, I'd suspect a loose wire.
Two weeks ago, the fridge freezer blew not only the plug fuse but also tripped the main switch.
It's been there 15 years, never been moved and never unplugged.
When I undid the plug the Brown wire had a loose strand sticking out that had touched the Blue wire - how I do not know because this was "tinned" with solder yet there was no sign of any solder left.
It's a mystery but not the first time I've come across this as at work we get it all the time but then, plugs are often taken out and put back in again but even those that are NOT moved at all do the same. stevmk2