Overloaded circuit? Breaker box woes? Wiring? Haunted house?

I apologize in advance because I come into this forum and my first post is a question. And because this is going to turn into a book..

Three months ago we bought a new microwave (1500w input power) to replace an old model . Worked great for three months but about a week ago the microwave started to shut down after running for over three minutes. The entire unit will lose power and the display will go blank. After about five minutes of sitting the display will come back on.

Figured it was a bad microwave. Returned the unit and got a new one of a different brand. Same thing happened. Would run for a few minutes and then shut down. Went back to the store and got my original micro back because it had more features.

Tried moving it to a different outlet. Same problem. Tried moving it to a different outlet on a different circut. Same problem. Tried moving it to an outlet with a GFCI outlet (our house only has two of them), and had the same problem. It shut down without throwing the GFCI on the outlet. Its not throwing a breaker. I have tried the microwave on eight differnent outlets in the house. Same problem. I can run a lamp in the same outlet while the microwave is running and it will still shut down after three minutes and the lamp will stay on.

I went so far as to shut every breaker off in the house and everything off in the circut the microwave was on. The microwave was the only thing in the house with power. After around three minutes, the microwave shuts off and the display goes blank. Same problem no matter what I do.

EXCEPT... The garage. As I typed this out, I hauled the micro to my attached garage and it ran for two seven-minute cycles with no problems.

So to recap with additional info:

1500w input power, 1000w energy output from the microwave, no idea what the old microwave was rated at. Same thing happened when I got a replacement micro from the store.

Only two GFCI outlets in the whole house, at no point was either tripped.

Breakers are not tripping and I can use the same outlet for any other electrical device I own.

The house was built in 1977. I bought the house nine months ago, bought the microwave three months ago. First problem was last week.

According to the breaker box, the garage is on its own 15 amp breaker. Its probably around 15 degrees out in the garage right now, as opposed to 65 in the house.



I have decent mechanical knowledge but I know more about cars than houses and electricity, and I have searched the net for problems like mine for around three hours now. I am thinking something must be wrong with all of the wiring in the house or the breaker box. I took a picture of the breaker box in case that helps.

https://scontent-b-lga.xx.fbcdn.net/...92704652_n.jpg


Any help or direction would be greatly appreciated!

 

I don't like that transformer sitting inside the box without being mounted. But that's neither here nor there.

Have you tried a 1500 watt space heater? Will that also shutdown? Do you have aluminum wiring? Do other appliances show any odd behavior?

Looking to hear what our experts have to say on this one.

 

That right there rules out plenty of stuff.

It sounds to me like your microwave is overheating and shutting itself down. Now why two different microwaves from two different manufacturers would do that, that one I can't figure out. I'm assuming you had something in the microwave when you did all this testing with both ovens? Did you remove all of the packaging material from around the vents? Are you getting air flow from the fan?

 

Right now I'm running a 1500w space heater/fake fireplace AND my 20 year old microwave (Admiral, unknown wattage) that was supposed to be replaced by the one I bought three months ago (Sharp) in the same outlet. Have been for about ten minutes.

Since I went back to the store to get my Sharp micro back, I can't double check the packaging on that one (was a Kenmore, adding brands to these so its easier to keep track). But I am certain the Sharp is free of packaging and there is nothing inside it.

I had thoughts that maybe if it senses there is nothing cooking in the micro it shuts down but that wouldn't explain why it shuts totally off and the display goes blank, and does not power back up for another five minutes. Everything is pointing to the micro EXCEPT the fact that I tried a different brand and the same thing happened, and that it works in the cold garage.

Starting to lean toward ghosts.

 

I think you may have hit on the problem. You were running the microwaves with nothing in them, empty? That's always been a No-No as far as I always read. :NO NO NO: If I'm not mistaken, running a microwave with nothing in it will cause it to overheat. You might try putting a large bowl of water in the microwave and setting it to run for 10-15 minutes and see what happens. You also might try reading the owner's manual and see what it says.

That would be consistent with the microwave overheating while running in your kitchen. My guess is there is a high temperature protector opening when the unit overheats that kills all power till the unit cools off.

 

No, there wouldn't be something in there that "senses there is nothing cooking", that wasn't what I was getting at. More like the thing is being blasted with microwave radiation and the thermal cutout trips when it overheats. You were seriously running this with nothing inside of it for 7+ minutes??

I'm not an appliance guy so obviously I'm out of my area of expertise. But it strikes me that if it's outputting 1000W that energy has to go somewhere. If the fan can't get rid of it fast enough then the thing must necessarily overheat. This is probably why it worked ok out in the freezing cold garage.

I'm surprised the thing still works at all. I always thought (possibly incorrectly) that you'd fry the magnetron in short order doing that.

Put a BIG bowl of water in there and try it.

[Edit. I see Joe beat me to it]

 

http://static.fjcdn.com/pictures/Tac...47d_374251.jpg


Ummm, yep, that did it. Ran with water in it for ten minutes.

I'm going to blame this on my girlfriend...somehow. She's the one who told me the thing wasn't working which led me to begin this battery of testing! Inaccurate and misguided testing!

And to top things off my full name is displayed because I registered with Facebook! Now everyone knows I don't know how to run a microwave!

Thank you for your help guys, and sorry for wasting your time. Although I can guarantee I have wasted more time!

 

The bright side is, now you know how to boil water......in a microwave.