Microwave Suddenly Stopped Working - Hot & Neutral Wires Reversed

[Skeezix]

My house was built in 1982. When I bought it in 1995 it had a GE Spacemaker microwave oven. It has been working without problems - until this morning.

As I was about to set the cook time I noticed the display was black. In the past it showed the time. I pressed a couple of buttons but the display remained black.

I unplugged the oven and put in my receptacle tester. It told me that the hot and the neutral were reversed, so I switched them to where they were supposed to be, plugged the oven back in, and Voila! The display came on!

So how is it that the oven worked at least for 24 years (and probably worked since 1982) with those wires reversed and then suddenly stopped working???

 

[nealtw]

That is strange.

 

[bud16415]

I suspect it is a coincidence. Having the wires reversed is not a good thing but should have no effect on the unit working. My guess is you had some corrosion in the plug/outlet and pulling the plug and inserting the tester cleared it enough.


Time will tell if the unit is failing and the problem was in the unit as an intermittent failure.

 

[JoeD]

Hot neutral reverse will not stop MW from working. I think it was just a coincidence that it started working after you swapped them. Maybe one of them was loose or somewhere else on the circuit there is still a loose intermittent connection.

 

[Skeezix]

Must have been one of my senior moments. Thank you all for your replies. If there is a problem, I'm sure it will return - just don't know how long it will be

 

[nealtw]

Must have been one of my senior moments. Thank you all for your replies. If there is a problem, I'm sure it will return - just don't know how long it will be

You turned off the breaker when you re wired the outlet. Maybe the breaker had popped. Some don't look any different.

 

[ajaynejr]

Branch circuits usually daisy chain from one receptacle to another, here, when getting to the receptacle behind the microwave oven. A loose connection could develop spontaneously in any of the outlet boxes along the daisy chain although a wire broken between outlet boxes is extremely rare.

The hot and neutral did not suddenly reverse themselves. Your circuit tester is a toy as opposed to a tool and could not tell the difference between an actual hot neutral reverse and some other conditions. A multimeter is a tool worth owning if you expect to do your own electrical work.

Using the multimeter you should measure about 120 volts from hot to neutral, about 120 volts from hot to ground, and nearly zero volts from neutral to ground.