Improperly-made connection eventually opened up. One possibility is a loose wire nut
somewhere on the neutral conductor for the circuit the GFI is on.
Another possibility is a mouse making contact between two conductors (don't scoff, I've
seen that happen).
Something strange is going on here, which is why I advised Brian to get an electrician out
ASAP. Tough to try to diagnose this from 800 miles away. Somebody needs hands-on.
Sure it could. Loose wire nut falls off, connection comes apart, neutral conductor comes in
contact with an equipment grounding conductor.
Not very likely, I'll grant. But it's still a possible scenario.
Whatever it is, it's got to be something strange. No possible fault in the stove could be
causing stray voltage on a completely separate 120V circuit -- therefore the two circuits are
not completely separate.
On 7/11/2013 12:32 PM, firstname.lastname@example.org wrote:
Did you test with the stove breaker ON, but the stove itself not plugged
into the outlet? I don't have a particular scenario in mind, but you
might as well find out if the stove itself has anything to do with it.
On Thursday, July 11, 2013 12:40:49 PM UTC-4, Greg Guarino wrote:
d to throw a GFI outlet on a separate circuit (110V) when my wife turned th
e oven light on. Now it's started to throw the same GFI at random times ev
en when the oven is not in use.
three lights on but dim. When I unplug the oven (on the dedicated 220V cir
cuit) the 110V GFI checks out 'correct' with the tester.
ld) has a component that has gone belly up.
the GFI tests normal (two right lights). When I leave the tester in the ou
tlet and turn the breaker 'on' for the stove circuit the two right lights o
n tester 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 'o
ff' position at breaker.
On Thursday, July 11, 2013 1:08:49 PM UTC-4, Leon wrote:
ted 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.
l three lights on but dim. When I unplug the oven (on the dedicated 220V c
ircuit) the 110V GFI checks out 'correct' with the tester.
old) has a component that has gone belly up.
x 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 tester go dim and the left most light flickers. When stove is unplugge
d and I repeat there is no difference at tester when circuit is in 'on' or
'off' position at breaker.
I'd have to swap out the plug on the saw to fit the 50A 220V receptacle. M
ight be worth the trouble.
Not all three-light testers are the same; it would help to know if yours is the same as mine:
(Amazon.com product link shortened)
Assuming that it is, then this pattern of lights means that you have hot current on both the
ground and the neutral.
If you don't have a voltmeter, get one. The Harbor Freight $2.99 multimeter is actually a
pretty decent piece of gear.
Then do these tests:
1. Unplug the stove, turn the breaker for the stove circuit ON, and turn the breaker for the GFI
outlet OFF. Measure voltage between hot and neutral, hot and ground, and neutral and
ground at the GFI outlet. All three readings should be zero (or possibly a small fraction of
1V). Plug your tester into the outlet. All three lights should be off. If you read voltage here, or
if the tester lights up, STOP, call an electrician.
2. Check voltage at the stove receptacle: hot1 to hot2 (240V expected), hot1 to neutral
(120V), hot1 to ground (120V), hot2 to neutral (120V), hot2 to ground (120V), neutral to ground
(zero). [If the stove has a three-wire plug, omit the hot to neutral tests.]
3. Turn the stove breaker OFF, and the outlet breaker ON. Repeat the voltage
measurements at the stove receptacle. All voltages should be zero.
4. Repeat the voltage measurements at the GFI. Hot to neutral and hot to ground should be
120V, neutral to ground should be zero.
5. With the stove still unplugged, measure the resistance between the two hot prongs on the
stove plug. I think you'll see something between 5 and 10 ohms.
6. Measure the resistance between each hot prong and the ground prong on the plug. If it's
a 4-wire plug, repeat for hot to neutral. Let me know what you get for these measurements.
On Fri, 12 Jul 2013 18:46:34 +0000 (UTC), Doug Miller
5 to 10 ohms across L1 to L2? That would be a 25 amp load with
everything shut off. I don't think so!!! Between hots there should
be virtually infinite resistance. Between one line and neutral/ground
you should see better than 50 ohms - ideally closer to 500 ohms -
which is the clock / controller load. With the oven door open that
should drop to 220 ohms or less (40 watt 120 volt).
Turn on any element and the line to line should drop to something less
than 20 ohms.
On Thursday, July 11, 2013 2:36:35 AM UTC-4, email@example.com wrote:
I found one loose neutral on the neutral bus bar that I tightened down. Still I was reading incorrect w/ the three light tester (TLT for here).
I found a GFI I installed a while back (dedictaed circuit) that had broken free of the dry wall. The plastic fins broke off apparently from an extension cord pull.
I replaced the two plastic fins and anchored down again. So far I am reading correct on the "faulty" gfi and the oven is plugged in w/ light on.
Lets see if she trips the gfi.
I inspected the receptacle that came loose from the drywall for signs of arching and I saw none. Looked clean.
One never really knows, might be a loose screw in the main circuit box.
When the stove draws current it might be putting some current on the
ground (safety) line. That would dump a GFI.
On 7/11/2013 1:36 AM, firstname.lastname@example.org wrote:
Does the stove/oven have a 3 Pin (L1, L2, G)or 4 Pin (L1, L2, N, G)
A 3 Pin (L1, L2, G) plug indicates that any 120V loads are being fed
by on leg (L1 or L2) and ground (G).
A 4 Pin (L1, L2, N, G) plug indicates that any 120V loads are being
fed by on leg (L1 or L2) and neutral
Either of these will generate an unbalanced load that may be
significant enough to trip a GFI receptacle depending on how the
circuitry in the house is wired.
The 3 Pin will be a tougher problem to chase down.
You indicate that if the stove/oven is unplugged, the GFI doesn't
If that is true, the stove/oven could be the problem, especially if
there is a loose connection someplace in the stove/oven or back at the
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