My electric oven is on its own 220V 50amp circuit. It recently started to throw a GFI outlet on a separate circuit (110V) when my wife turned the oven light on. Now it's started to throw the same GFI at random times even when the oven is not in use.
I checked the GFI receptacle w/ a three light tester and it shows all three lights on but dim. When I unplug the oven (on the dedicated 220V circuit) the 110V GFI checks out 'correct' with the tester.
What the heck is going on? My gut tells me that the stove (15 years old) has a component that has gone belly up.
Very strange. Unless the two circuits are wired together somehow, what happens on one should not cause a GFCI to trip on the other. My first suspicion would be that there is something wrong with the GFCI and I'd try replacing it.
There seems to be some weird interaction going on, possibly inside the breaker panel? I would inspect the neutral and ground connections to the bus bars for both circuits and make sure that they are good and tight, and also that none of the hot wires for any of these circuits are touching each other (e.g. wires stripped too long where they enter the breakers, and somehow making contact.) Whatever the issue is it should definitely be fixed!
Additionally keep in mind that stoves are weird (as are electric dryers) usually one would expect a dedicated ground conductor for that circuit as is normal for every other branch circuit. However up until fairly recently it was normal practice to only pull a three conductor cable (hot, hot, neutral) to those outlets and at the appliance connect the case of the appliance to neutral - which means that the case of a stove or electric dryer is connected to a potentially current carrying conductor. If everything is working correctly this is not a problem as it should always be at 0V but that is assuming, as I say, that everything is working correctly... so if you identify a bad neutral situation and you can't fix it yourself you should unplug the stove and not use it until the issue is corrected.
Unless you're familiar with "hot work" I would definitely throw the main breaker before taking the breaker panel cover off, and even then approach with extreme caution as the service wires coming in from the meter are still live and definitely have the potential to kill you. If you're not comfortable with that, you know what I'm going to say next...
to throw a GFI outlet on a separate circuit (110V) when my wife turned the oven light on. Now it's started to throw the same GFI at random times eve n when the oven is not in use.
hree lights on but dim. When I unplug the oven (on the dedicated 220V circ uit) the 110V GFI checks out 'correct' with the tester.
d) has a component that has gone belly up.
I swapped out the GFI and I still test 'bad' with outlet tester.
With the stove plugged in and circuit in 'off' position at breaker box the GFI tests normal (two right lights). When I leave the tester in the outlet and turn the breaker 'on' for the stove circuit the two right lights on te ster go dim and the left most light flickers. When stove is unplugged and I repeat there is no difference at tester when circuit is in 'on' or 'off' position at breaker.
This is a problem that has steadily worsened with the GFI tripping. I am v exed.
I'm making the assumption that the two circuits are completely separate once they leave the breaker box. Your additional info leads me to believe that the next logical step is to open up the breaker box and look inside. I'm really not sure what you'll find but it just makes sense that that's the next place to look.
Good suggestion. I just don't understand why I only fail a test at the 110V receptacle when my stove is plugged into a separate cicuit. Wouldn't a lose connection fail a test whether the stove is plugged in or not?
I'm imagining something weird like someone added a supplemental ground from the stove to a water pipe or something and that is being used as the neutral because of a loose connection? but then you'd still have to have another fault near the GFI. *shrug* this is actually a pretty good head scratcher.
Is this by chance a really old house that was originally wired with ungrounded cable, and was fitted with supplemental grounds tailed to the nearest ground point, back when grounding to copper water pipe was acceptable?
If so, that combined with a loose neutral somewhere, *might* explain your issue. I think. I'm kind of thinking out loud in this thread and need to brain on it some more.
I am thinking along the same line. If there is not a loose wire somewhere, it is beginning to sound like the house has been wired in a shotty way and maybe gounds and neutral wiring is ran all over the place instead of being done correctly. The circuits would work , but when a GFCI is installed, it will trip because of unballanced currents.
I wouldn't call it "shoddy" - I have seen before in older homes e.g. a dryer having a ground wire run from the case to the cold water hookup for the washing machine. It's actually a pretty smart idea; even better if it's sized properly and the bonding jumper is removed, even if it doesn't meet current code. In effect you are providing the function and protection that is now provided by the required 3 conductor plus ground cable and four wire cord that is required for new construction. (of course, I just installed a range into an older house that was removed from a newer house when the owner upgraded... it had a four wire cord on it but the bonding jumper wasn't removed. Saved me the trouble of making up a heavy gauge pigtail, but clearly whoever did that didn't realize why the four wire cord was there in the first place...)
Likewise with pigtail grounds on an older house... it wouldn't meet code for a new installation, but it is making the best of a bad situation if done right.
Now mixing neutrals... yeah, bad juju. But it would take a real idiot to think that splicing a 6AWG wire to a 14AWG wire in an intermediate box (and really, there shouldn't be any - at least the range should be a straight run back to the panel) is a good idea. But every time I say something like that someone shows that such an idiot actually exists.
I wouldn't call it "shoddy" - I have seen before in older homes e.g. a dryer having a ground wire run from the case to the cold water hookup for the washing machine. It's actually a pretty smart idea; even better if it's sized properly and the bonding jumper is removed, even if it doesn't meet current code. In effect you are providing the function and protection that is now provided by the required 3 conductor plus ground cable and four wire cord that is required for new construction. (of course, I just installed a range into an older house that was removed from a newer house when the owner upgraded... it had a four wire cord on it but the bonding jumper wasn't removed. Saved me the trouble of making up a heavy gauge pigtail, but clearly whoever did that didn't realize why the four wire cord was there in the first place...)
Likewise with pigtail grounds on an older house... it wouldn't meet code for a new installation, but it is making the best of a bad situation if done right.
Now mixing neutrals... yeah, bad juju. But it would take a real idiot to think that splicing a 6AWG wire to a 14AWG wire in an intermediate box (and really, there shouldn't be any - at least the range should be a straight run back to the panel) is a good idea. But every time I say something like that someone shows that such an idiot actually exists.
The stove, on a separate 240 volt circuit, should not affect a separate 120 volt circuit GFCI. However, since it happens when she turns on the 120 volt oven light - which is on one side of the 240 volt circuit, I'd be looking for a bad neutral at the panel which is throwing the cirduit out of balance - causing an unbalanced current flow on the GFCI
Maybe not. A loose connection on a wire that carries no current is not going to affect anything. Your stove probably as a clock, at least that runs all the time.
Is your stove electronic, or just an old fashioned stove with switches and "burners".?
I agree with the suggestions about the neutral etc, but if those don't work, testing the stove if is non-electronic will be simple. And then just replace the single part that is bad,
I still can't see how an unbalanced anything at the panel is going to trip a GFCI outlet. The GFCI outlet is only comparing the current leaving it and anything downstream it also protects, with the current coming back on the neutral. Regardless of what is happening back at the panel and the oven, those currents at the outlet would be the same.
For this to be happening, you would think there would have to be something either plugged into the outlet or connected downstream of the GFCI outlet that is somehow linked back to the oven.
If there is not a solid ground for the GFCI the H-G and N-G test lights could change brightness. The brightness of the H-N light should not change. (The 3-lite testers don't give a reliable test for whether there is a good ground back to the panel.) I don't see a reason the test lights should change brightness when the stove is turned on if the wiring is correct. And a properly wired GFCI will work if there is no ground.
Measuring the H-G, N-G and H-N voltages with the tester plugged in and stove turned on would be interesting.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.