Microwave blowing breaker constantly

[MarkG]

I'm no electrician, so here's the dilemma. I use our microwave mostly to boil water for coffee, etc. Just a single cup of water at a time in a Pyrex measuring cup. But lately, before it even comes to a boil, the breaker blows! It's getting very annoying running downstairs and re-setting it all the time.

Do breakers 'weaken' over time? Can an electrician safely use a bigger breaker? The microwave seems to work fine otherwise, but could it be a problem with the oven? I just need to know if I need an electrician, or a new microwave!

Thanks.

 

[kd3pc]

Most likely a problem with the microwave, or overloading the circuit when it is being used. One would need to see what else is "running" on that circuit...plugged in is OK, but not running...just use the microwave and see if it runs without kicking off the breaker.

You could move the microwave to a different outlet, on another breaker and try it.

It is possible that a breaker is bad, but it would be consistently bad in most cases..

try these and let us know what happens.

 

[wyliesdiesels]

What else is on the circuit?

Breakers are sized based on wire size.

What size breaker do you currently have?

 

[Gittgo]

Microwaves are generally on the counter with the refrig. coffee machine, toaster, toaster oven, can opener and every other useless pizzachit in a kitchen.
Get an electrician to add a second 20 and put the fridge and microwave on one and all the other ****(including dead shorts like a toaster and toaster ovens) wired to the other.In all reality and electric range-oven should have its own too......if there's room for the breaker. I had the same problem here.That fixed it.Similar to guys blowing breakers when the welder or table saw are on the same 230 amp breaker as a clothes dryer. You're running the welder and on comes the dryer...****.

 

[ard]

I would try and replace the breaker- it is the easiest POSSIBLE solution.

DO keep in mind that a microwave oven is NOT a constant current draw- due to coupling to the media (i.e. Water) the power draw varies with what you are heating. A large amount of water is differnt than a plate of food with an ounce or two of water content.

So you can't use "it doesn't blow all the time" to decide the breaker must be ok.

Might not be the breaker, but could be- and they can go bad over time.

GL
Report back

 

[jrsulo]

A lot of times people add a over the stove micro where a vent hood used to be,,,,using the wire that was already there,,,,is it a over the stove or on the counter ???

 

[Milton Shaw]

As a microwave repairman I would say , Replace the breaker with a good quality breaker. Some box store breakers trip at very low amps. All microwaves I have ever seen have a 15 amp fuse in them that will blow at the slightest problem in the microwave, such as a safety door switch failure. The surge when a microwave starts up will trip a cheap breaker often. The better magnetic breakers in commercial use will handle that surge with no problems the cheap China home line breakers will not.

 

[kbs2244]

Check what else is on your circuit.
My "professionally installed" unit shares a wall with our DR.
They wired it in with the DR light switch.
The problem is the DR light is a multi bulb chandler.
We can't use it with the DR light on.

 

[Nailset]

I have a dedicated 20amp circuit for the microwave.

 

[ard]

Something has changed in the OPs situation OVER TIME.

He didn't just move in and it always blows. It was working and now has begun to not work when he heats large amounts of water.

Hence I would look at ONE 'thing' that has changed:

1. You moved something onto the Mic circuit
2. The Mic is drawing more current due to internal failure
3. A breaker is beginning to fail.

Anyone think of anohter cause that fits the OPs fact pattern?? Not what you experienced, but fits these facts....

 

[wyliesdiesels]

As a microwave repairman I would say , Replace the breaker with a good quality breaker. Some box store breakers trip at very low amps. All microwaves I have ever seen have a 15 amp fuse in them that will blow at the slightest problem in the microwave, such as a safety door switch failure. The surge when a microwave starts up will trip a cheap breaker often. The better magnetic breakers in commercial use will handle that surge with no problems the cheap China home line breakers will not.

Which breakers are you referring to that are good quality? There is no way a brand new breaker would trip at a lower amperage than it was designed to trip at.

Breakers have bimetallic elements that heat up during overload then trip after a short overload condition.

And seeing as how one can only use breakers that are listed for the panel they have, cant just use any "good quality breaker". Has to be same brand and model as listed on panel.

 

[wyliesdiesels]

I have a dedicated 20amp circuit for the microwave.

What brand and model breaker panel do you have?

 

[ard]

What brand and model breaker panel do you have?

The highest quality one.

 

[thammel]

It could be a problem with your microwave. I have a Wolf microwave that does that when one of the door safety micro-switches fails. They fail from time to time due to overheating. I replace the faulty one and then all is ok. I've had to replace the microswitches, a fuse and the mica microwave diffuser. Other than that it's been good.

Tom

 

[walta]

A “monitor interlock switch” of the safety strategies often used in microwave oven.

The idea is when the door is open the monitor switch disconnects power from the high voltage transformer and also connects both side of the transformer together so it is impossible to make high voltage and microwaves with the door open.

This works great until the switch gets worn or sticky. If the power gets connected before the transformer gets disconnected an overload must open. The overload may be the fuse in the oven or the breaker in the panel depending on how the circuit was designed.


Walta