Fuse blowing when door is opened

Here’s an answer I’ve not seen elsewhere: Over time the door latch wears down such that the timing of the interlock switches gets confused. There are three switches that must activate in the correct order. When the latch is worn, the timing of the two lower switches is disrupted. After trying everything else (and I mean EVERYTHING), I noticed the worn latch and started experimenting, opening and closing the door very slowly and listening for the switches to activate. They must be out of sync, somehow. How can I correct it? Believe it or not, I simply wrapped some duct tape around the tip of the lower black plastic latch. This caused one of the lower switches to activate a fraction of a second sooner . . . before the second switch . . . and the problem was solved.

SOLVED:

I took away the switch in the middle. That switch simply short 120 AC power when door opens. If there still power, it just blow the fuse. It is overkill, because another switch (top one) opens when door is open and cancel 120AC power from outlet. It is double protection (not necessary for my opinion). Timing is the problem and with flimsy plastic supports of all three switches shortening switch can close before power interrupted by top (power) switch. That will blow the fuse. And one can change a dozen of switches and other parts, but will have the same problem. Can try to redesign switch support, adjust switches position making timing reliable, but just eliminating shortening switch is an easy and fast solution. I blew up four fuses in couple weeks, but now microwave works without problems.

Most homes have circuitry that's limited to a 3000w per set and you can have multiple sets such as when set runs the ceiling lights other sets run other rooms walls or sections of the house. However just 3,000 watt limit makes it so you can't run a frigerator the toaster and a heater or a microwave on the same circuit. If that was your case there would be some understanding of why you could be tripping the circuit when you open the door in microwave but I don't think that's your case. You should test the microwave on an unoccupied circuit (that is one that has little or nothing plugged into it most likely a garage). If the device were to trip the circuit all by itself that would mean that there is a short within the microwave and the door could be all or part of the trigger. A spot where our concurred should be noticeable you are in fact creating a surge which is what trips the breaker and this should be noticeable if you were to get inside it. Since you have a limited electrical knowledge I would recommend replacing the unit strictly on the grounds that is much safer than having a microwave burn down in your kitchen.