# Microwave trips GFCI?



## kcrossley2 (Dec 17, 2006)

I have an over-the-range microwave that trips a no-load grounded GFCI circuit, but it does not trip a regular circuit. GE has replaced the microwave control board under warranty, but it just burned out again. Has anyone had this happen to them and if so what was the problem?


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## romex1220 (Jun 26, 2013)

kcrossley2 said:


> I have an over-the-range microwave that trips a no-load grounded GFCI circuit, but it does not trip a regular circuit. GE has replaced the microwave control board under warranty, but it just burned out again. Has anyone had this happen to them and if so what was the problem?


A gfi isn't an over current protector like a breaker is. A gfi monitors for a ground fault by monitoring the amperage between the hot and neutral so if the hot is pulling 2 amps the neutral must be returning 2 amps or it will trip. It will trip within a 5,000 of an amp so very sensitive especially electronics that leak minute current like microwaves. 

A microwave should be on its own 20 amp circuit and an over range microwave doesn't need a gfi


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## Philly Master (Mar 30, 2013)

what size is the curcuit ??


what size is the actual GFI outlet ??


as the micro ages it uses more !


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## sparks1up (May 5, 2010)

The outlet for the microwave is probably using the neutral from the load side of the GFCI circuit. The microwave should be on it's own dedicated circuit. It may be on a dedicated circuit but sharing the neutral from the load side of the GFCI. If it is sharing the neutral but is a dedicated circuit otherwise you might be able to trace out the neutral and connect it to the line side of the GFCI.


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## MTN REMODEL LLC (Sep 11, 2010)

Does this thread make sense to anyone????... 

....from a "no-load grounded GFI circut" (first post) to " on a dedicated circuit but sharing the neutral from the load side of the GFCI" (last 4th post).


:huh::huh::huh:


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## hidden 1 (Feb 22, 2009)

it is not set up to be on a gfci ,only a regular dedicated 20 amp outlet with nothing else on it.
if you change it to how it is required -no gfci-does it effect the breaker?usually not on regular 20 amp.
do you have 12/2 wire on it? and is the - gfci/single outlet for 15 or 20 amp?


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## kcrossley2 (Dec 17, 2006)

Philly Master said:


> what size is the curcuit ??
> 
> 
> what size is the actual GFI outlet ??
> ...


The microwave's dedicated outlet is 20 amps. The GFCI circuit the GE tech plugged the microwave into is 15 amps. He plugged it into the GFCI protected circuit because he was working on it on our kitchen island and didn't think to run an extension cord to microwave's dedicated outlet. Unfortunately, I wasn't home to catch that mistake. The microwave is new. It was built in the fall of 2012.


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## kcrossley2 (Dec 17, 2006)

I have another thread dedicated to my whole GE microwave fiasco if anyone is bored and wants to read the entire story: 

http://www.diychatroom.com/f47/haunted-ge-microwave-oven-turns-itself-183986/


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## Philly Master (Mar 30, 2013)

try googling a "runaway oven" ......


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## Speedy Petey (Feb 1, 2004)

hidden 1 said:


> ..............
> if you change it to how it is required -no gfci-does it effect the breaker?usually not on regular 20 amp.
> .............


?????????


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## Speedy Petey (Feb 1, 2004)

kcrossley2 said:


> The microwave's dedicated outlet is 20 amps. The GFCI circuit the GE tech plugged the microwave into is 15 amps. He plugged it into the GFCI protected circuit because he was working on it on our kitchen island and didn't think to run an extension cord to microwave's dedicated outlet. Unfortunately, I wasn't home to catch that mistake. The microwave is new. It was built in the fall of 2012.


None of this should affect the performance of the microwave. The fact that the GFI is a 15A configuration is meaningless, it's still a 20A feed-thru device and the only thing that makes it 15A is the prong configuration of the two receptacles on the face.


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## Kyle_in_rure (Feb 1, 2013)

I read your haunted microwave post...might I suggest getting a new one.... :laughing:


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## dmxtothemax (Oct 26, 2010)

Try moving the microwave to another area of the house,
And try it on another gfci circuit,
See if it trips it out as well,
This will tell yo if the problem lies with the microwave itself ?
Or the circuit and wiring. ?

If it does, then replace it !
If not, then you have to check your wiring !


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## kcrossley2 (Dec 17, 2006)

Kyle_in_rure said:


> I read your haunted microwave post...might I suggest getting a new one.... :laughing:


Unfortunately, I can't. GE discontinued this model and the only ones I've been able to locate are either refurbished or closeouts. Most are scattered throughout the US and cannot be shipped, because they are missing their packaging. The one I purchased from Sears was a new display unit, which had never been installed. This is replacing the same model that recently failed, which means it matches up perfectly with the existing cabinet holes and wall mount.

The thing that makes this microwave unique is it's a 36" width above-the-range, which is very, very difficult to find.


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## kcrossley2 (Dec 17, 2006)

dmxtothemax said:


> Try moving the microwave to another area of the house,
> And try it on another gfci circuit,
> See if it trips it out as well,
> This will tell yo if the problem lies with the microwave itself ?
> ...


We checked all of the circuits and they are all properly wired and grounded, and are performing as designed. Whatever the issue with the microwave is it's significant enough to trip the GFCI, but not the breaker. 

Unfortunately, this model has been discontinued, so replacements are nearly non-existent. This is also why I'm giving GE some latitude in trying to repair the microwave.


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## Kyle_in_rure (Feb 1, 2013)

kcrossley2 said:


> Unfortunately, I can't. GE discontinued this model and the only ones I've been able to locate are either refurbished or closeouts. Most are scattered throughout the US and cannot be shipped, because they are missing their packaging. The one I purchased from Sears was a new display unit, which had never been installed. This is replacing the same model that recently failed, which means it matches up perfectly with the existing cabinet holes and wall mount.
> 
> The thing that makes this microwave unique is it's a 36" width above-the-range, which is very, very difficult to find.


I see why that might complicate things. 

Worse comes to worst you could always frame a new one in...


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## dmxtothemax (Oct 26, 2010)

If your really keen to keep it !
Try taking it to a good electrical/electronic engineer
and ask if they can find where the leak is originating from
once you know that, there might be a way to modify it.
This might cause issue's with listing thou !


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## kcrossley2 (Dec 17, 2006)

dmxtothemax said:


> If your really keen to keep it !
> Try taking it to a good electrical/electronic engineer
> and ask if they can find where the leak is originating from
> once you know that, there might be a way to modify it.
> This might cause issue's with listing thou !


Actually, I've lightened up a bit and I find this whole thing fascinating. It would probably be more frustrating if I didn't have a backup microwave. 

I'm curious to see how much GE will spend on warranty repair work (parts and labor) before they replace the product. So far, they've invested in two service calls and 1 control board. By this coming Monday, it'll be a second control board, a magnetron, and another service call.


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## dmxtothemax (Oct 26, 2010)

The fact that they are replacing parts to see what happens,
Tells me that they don't know what they are doing,
The electrical leak might not be a fault as such,
just a percularity of that design,
It works fine on a non GFCI circuit doesn't it !
So the problem is just a small electrical leak,
Small electrical leaks are not new, and have been around
for a long time. And usually the ground system just bleed it off.
But now with the use of gfci's it's becoming a problem.

To fix the problem, someone who really understands electricity
has to sit down and think about the ovens circuit diagram and how it works,
Then when he knows the problem, then he might be able to re configure the
circuit to avoid the leakage.


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## kcrossley2 (Dec 17, 2006)

dmxtothemax said:


> It works fine on a non GFCI circuit doesn't it?


Supposedly, the tech had it working on a GFCI, just not the one he originally connected it to. When he changed GFCI's it worked, but when I connected it to the microwave dedicated non-CFGI outlet I smelled electronics burning and the microwave promptly shut off. After 30 minutes or so I was able to reset the microwave, but now the magnetron powers on with the door closed and no user input regardless of whether it's on a GFCI or non-GFCI circuit. Open the door and the magnetron shuts off.

Aside from changing the power to a standard outlet, the ONLY other thing that could be triggering a problem are the 4 long screws that secure the microwave to the top cabinet. I suppose they could be creating a short when screwed in, but I would think that would be highly unlikely.


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## carmusic (Oct 11, 2011)

it may be normal for some electronics boards to leak to ground some mA, they are designed like this to avoid floating voltage that could create static electricity. i work with a lot of electronics componenent like dc/dc converter, power supplies and most of them leaks a little, but most of the time not enough to trip a gfi, but you may have a too sensible GFI


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## curiousB (Jan 16, 2012)

carmusic said:


> it may be normal for some electronics boards to leak to ground some mA, they are designed like this to avoid floating voltage that could create static electricity. i work with a lot of electronics componenent like dc/dc converter, power supplies and most of them leaks a little, but most of the time not enough to trip a gfi, but you may have a too sensible GFI


Yeah but no. GFCIs trip at a few mA. Any electronics product should leak to ground at most in microA range... Something is wrong on primary side of microwaves power supply. Maybe a leaky capacitor or MOV to ground.


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## dmxtothemax (Oct 26, 2010)

What is the trip point of your gfci ?


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