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.
Anyone have any thoughts on this?
My non-professional guess is that the GFI receptacle has gone "bad", and
that the tester isn't sensitive enough to detect the problem. To me,
swapping out the receptacle seems like the obvious step to take before
calling a professional. Your mileage may vary based upon your wisdom
and experience. You have me curious, please report how it works out.
Probably, the cables for the two circuits are close together, and the current in the oven
circuit is inducing a small current in the other circuit -- causing nuisance trips in a failing
I agree with Bill: first thing I'd do is replace the GFCI; it's a cheap and easy job. If the
problem goes away, rest easy. If the problem persists, it's time to talk to an electrician.
I agree that something's gone belly up, but IMHO it's far more likely to be the GFCI.
One last thought: post in alt.home.repair instead of here. There are at least two licensed
professional electricians who read and post there regularly, and their advice is to be
trusted: "RBM" and "gfretwell".
Some of the newer GFI's now detect a slight problem with say a bad wire
on a lamp cord, no short, but too much resistance. The oven probably is
using some current all the time, such as the clock.
I would suspect the GFI becoming way too sensitive to that possibility.
When there's nothing but the clock and whatever other micro-processor
loads only, the current flow to the range is miniscule. If that were
able to induce sufficient current to trip the GFCI in the second circuit
it would never stay on, not trip randomly. I stick w/ contention it's
more than likely unrelated to the range even tho I agree w/ the fault
probably associated w/ the GFCI itself.
Your example is a fault on the circuit in question, not some phantom
induced current from another circuit. Think it highly unlikely since
the problem now appears to be independent of the use and previously only
coincidental. Probably there's another appliance or particular light or
somesuch that is used when the range is used that was the culprit in
initiating the trip.
While you're checking this other stuff, check the main 220v receptacle
for the oven.
I don't know how old your house is, but they were using aluminum wire
for high current 220v to ovens and furnaces back in the day. Most
receptacles have copper connection. Aluminum to copper can spark and it
ends up melting the insulators and can be dangerous, obviously.
Check your wire connections to the receptacle in the box in/on the wall
to see if this is happening. If you do have aluminum wire, you don't
have to replace it. They make retro-fit receptacles with aluminum
connectors or copper that uses a dielectric grease to stop sparking.
"Playing is not something I do at night, it's my function in life"
When dissimilar metals are in contact, they can galvanically corrode. The
corrosion causes additional resistance, which leads to heat build-up. The
heat can build up to the point where nearby combustible materials will,
Aluminium conductors also expand and contract with temperature changes more
than copper; in smaller (AWG 12) gauge connections this may loosen
the connection over time, which also increases resistance which leads
to heat, which can lead to fire. This generally doesn't happen with
the connectors used for #6/#4 50A 220V recepts, if they are torqued correctly
Brian's problem is likley to be a loose neutral somewhere, or a
a three-wire 220 circuit injecting current into a shared ground because
the appliance (stove) is cheating by using one 220VAC leg and the ground
to get 120V for the oven light (since a three-wire circuit won't have a
grounded conductor, only a grounding conductor).
Opinions among electricians are as varied as among woodworkers. :-)
My buddy who is an EE with AEP told me when those connections do end up
loosening because of the reasons you describe, they will often spark,
causing a fire.
Whatever the specifics, you want to make sure yours is a safe situation,
installed correctly by someone who knew what he was doing.
"Playing is not something I do at night, it's my function in life"
On Thu, 11 Jul 2013 12:38:45 +0000 (UTC), Doug Miller
One other consideration depending on the age of the house was they
used to allow the ground on an oven to serve as the nuetral for the
stove. If there is a problem with the stove and there are bare
grounds in a common box, however I wouldn't expect that with a 50 amp
circuit but you never know. I to would first replace the GFI & see if
it is the problem.
On Wed, 10 Jul 2013 23:36:35 -0700 (PDT), firstname.lastname@example.org
I would agree that the first thing to do is to replace the GFI outlet.
If that does not solve the problem, I would tighten the screws on the
connections to these circuits in the panel box - especially the white
(neutral) and ground wires. You may have a poor connection in that
neutral in the box or even at one of the connections feeding the house
from the power company's trasformer. Doesn't happen often but can
cause all sorts of strange symptoms.
On Thursday, July 11, 2013 2:36:35 AM UTC-4, email@example.com wrot
ven light on. Now it's started to throw the same GFI at random times even
when the oven is not in use.
t) the 110V GFI checks out 'correct' with the tester.
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
I think it's time to call an electrician, Brian. The two circuits are cross-connected somehow --
possibly sharing a neutral -- and this is potentially *very* dangerous.
Leave the breaker for the stove off until this is resolved.
You're not anywhere near Indianapolis, right?
as paying him $80 to tell you that you *don't* have a problem in the *wiring*.
But I think he's going to find that you do.
In any event, once the problem is resolved, please follow up with a description of the cause.
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