GFCI Troubleshooting

Posted by bud-- on October 16, 2009, 12:54 pm

Robert Green wrote:

>>> I've had a GFCI outlet that powers a refrigerator and some kitchen and
>>> basement outlets trip twice within the last year. I've reset it after
>>> each trip and it seems to go another six months before it trips again.
>>> What's the best way to determine if this is just a random event or
>>> whether the GFCI is pointing toward a potential shock hazard?
>>> --
>>> Bobby G.

>> Refrigerators require their own dedicated circuit with no GFCI.

In the US refrigerators do not require their own circuit and can be
placed on a GFCI.

>
> That's probably the way it will end up as this is more or less a temporary
> wiring setup. We discovered halfway through a recent rewire other, more
> pressing problems when the basement plywood walls came down. Not an unusual
> situation, from what I've read here about remodeling. Several expensive
> mysteries were revealed that stalled the rewiring initiative. But I
> digress.
>

>> Kitchen receptacles require their own dedicated circuit/'s as well, They
>> need to be GFCI protected only if the receptacle is approximately five

> feet

>> from a water source (sink).

>
> I'm no NECspert but I thought anywhere near water meant GFCIs are preferred
> and that if you used them in drier locations, it was no harm/no foul.

As RBM(?) posted all kitchen counter top receptacles are required to be
on GFCIs (US). (Also required in some other locations - generally damp
related.) And can be used anywhere.

> I got
> my near-death lethal, burning skin, couldn't let go shock in my bedroom with
> a Dr. Scholl's foot bath and massager. I reached for a swing arm, imitation
> Luxo lamp and began to fry. A GFCI would have prevented that little mishap.
> Had gravity not intervened, I would have died that day with a
> foot-torso-heart-arm pathway for the shock that caused smoke to rise from my
> burning feet. For some odd reason, even though I was completely paralyzed,
> I still managed to fall out of the chair I was in and that broke my hand's
> connection to the metal lamp handle. That's when I went a little GFCI crazy
> and began installing them in all the household circuits as I upgraded from 2
> wire to grounded service.

Scary. I never had that close a call.

>> The occasional tripping maybe to due to the fridge motor kicking on while

> a

>> toaster or some other device is drawing power. Even a plug being pulled
>> quickly from a receptacle can arc and cause a trip of the GFCI.

> Regardless,

>> your circuit configuration is not acceptable under the current electrical
>> codes.

The configuration is acceptable in the US except the circuit extends to
the basement. (It can extend to dining rooms and some other locations.)

>
> Hmmm. Well, something else was on the same circuit and probably did fire up
> at the same time as the fridge. We've been having a lot of high winds and
> "power blinks" and there was a small air compressor plugged into the 2nd
> outlet of the duplex outlet that serves the fridge that I was using to blow
> out the coils. The lower half of the refrigerator duplex outlet was the
> nearest free outlet. They could have easily restarted within seconds of
> each other.

Producing an "overload" might trip a circuit breaker but won't trip a
GFCI. They only look for a current imbalance.

Older GFCIs were more prone to nuisance trip. I kinda forget - I think
several people suggested trying a new GFCI.

> I can certainly isolate the refrigerator on its own circuit and that seems
> to be a prudent thing to do. This could have happened when no one was at
> home.
>

>> You can buy inexpensive receptacle testers that will test a GFCI and other
>> receptacles for proper grounding. As long as the receptacle is properly
>> grounded, short circuits will go to ground and shock hazard will be
>> minimal.

>
> Got one that had disappeared for nearly a year to reappear at the bottom of
> the seasonal lights box. Will try that out today. Did that, and it says
> nothing's wrong.

If they indicate a problem there is very likely something wrong. If they
indicate OK the wiring is probably OK. But they can miss problems. In
particular, they can not check the the ground is good - they will
indicate good for a high resistance connection. Actually the same is
true for a high resistance hot or neutral connection, but you will see
the problem if you plug in a light.

> <...>
> o 25 years of watching This Old House. Despite what many people say, there
> isn't an episode where I haven't learned how to do at least one thing
> better. Tommy Silva is the one I've learned the most from, and Bob Villa
> the least. Sometimes it's something as simple as using a new blade every
> three or four trim cuts on wallpaper or as complicated as chasing down
> bizarre problems with hot water heating.

I wish they had an electrician as good as the other regulars.

--
bud--

Posted by Robert Green on October 19, 2009, 8:01 am

> In the US refrigerators do not require their own circuit and can be
> placed on a GFCI.

Sorry to start a cross-border dispute! (-: I should have mentioned North
East US.

> As RBM(?) posted all kitchen counter top receptacles are required to be
> on GFCIs (US). (Also required in some other locations - generally damp
> related.) And can be used anywhere.

That was my understanding. Thank you for confirming it.

> Scary. I never had that close a call.

It's a motivator. Bought two 250' rolls of 12/2 w/G and have been slowly
replacing 2 wire outlets and wires from the 1940's. Most importantly, I've
moved all the high current devices off the old wiring and left the old two
wire
outlets to serve things like 2 wire chargers, floor lamps and items that
never had grounds to begin with and that don't draw lots of current.

Turns out in an old Cape Cod that doing a rewire from the basement is a lot
easier than working with the old wires that went up to the attic and then
down throughout the house. Unfortunately, when we pulled down the poorly
refinished basement's ceiling and walls, the re-wiring effort was no longer
the top priority. For one thing there was a huge hole in the cinderblock
wall - it looked like someone had started tunneling out. Next time we buy a
house, we'll ask lots more questions if only 1 wall out of 4 in the basement
is panelled.

> The configuration is acceptable in the US except the circuit extends to
> the basement. (It can extend to dining rooms and some other locations.)

Yes, I knew when I crossed floors I was probably coloring outside the lines.
I did it in haste to at least temporarily protect both those areas with GFCI
I also tried to make sure that area was serviced by two different breakers
so I could still see if the GFCI tripped and took out the lamps on that
circuit. It's easy enough to rewire the correct way. Do you know the basis
for the rule? Is it that one breaker should not service two floors or that
one GFCI can't span floors or both?

<info about two different compressors starting at the same time snipped>'

> Producing an "overload" might trip a circuit breaker but won't trip a
> GFCI. They only look for a current imbalance.

What worried me is that there may be an underlying small ground current
leak - perhaps some insulation is degrading - and it only shows when the
GFCI warms up from carrying a larger than normal current and some capacitor
or resistor value shifts enough to make the imbalance detection circuitry
react differently. A while back Smarthome released new Insteon-brand
switches, and IIRC, they only exhibited flashing problems when the load on
the unit was beyond a certain limit. People with chandeliers and 300W
torchiers ran into serious problems with unwanted flickering and outright
flashing that users with small lamps (and probably most of Smarthome's beta
testers did not experience. I note that just to point out that devices can
behave quite differently under a heavy load than they do under a light one.

> Older GFCIs were more prone to nuisance trip. I kinda forget - I think
> several people suggested trying a new GFCI.

Yes, and that's underway as I noted elsehere. The unit in question is
perhaps a 25 year old Slater. I will swap it for a 2008 model Leviton.

> If they indicate a problem there is very likely something wrong. If they
> indicate OK the wiring is probably OK. But they can miss problems. In
> particular, they can not check the the ground is good - they will
> indicate good for a high resistance connection. Actually the same is
> true for a high resistance hot or neutral connection, but you will see
> the problem if you plug in a light.

No problems with any of the testers so far. Everything checks out. I am
pretty sure that this issue was caused by having other devices on the same
outlet. I'll be switching the fridge over to its own dedicated line later
this week and I'll also be switching out the older model Slater GFCI for a
newer Leviton 20A model. I'm hoping those two changes will eliminate the
nuisance tripping. If the problem occured more than once or twice a year,
I'd remove the GFCI entirely, but I'm reluctant to give up the protection it
ostensibly affords until it proves itself to be too troublesome to maintain.

>> 25 years of watching This Old House. Despite what many people say,
>> there isn't an episode where I haven't learned how to do at least one

thing

>> better. Tommy Silva is the one I've learned the most from, and Bob Villa
>> the least. Sometimes it's something as simple as using a new blade
>> every three or four trim cuts on wallpaper or as complicated as chasing

down

>> bizarre problems with hot water heating.

> I wish they had an electrician as good as the other regulars.

I agree. Still, they've taught me a lot. I wonder if they deliberately
chose not to focus on electrical work because of all the potential dangers.

Thanks for your input, Bud.

--
Bobby G.

Posted by terry on October 19, 2009, 8:48 am

wrote:

> > In the US refrigerators do not require their own circuit and can be
> > placed on a GFCI.

> Sorry to start a cross-border dispute! (-: I should have mentioned North
> East US.

> > As RBM(?) posted all kitchen counter top receptacles are required to be
> > on GFCIs (US). (Also required in some other locations - generally damp
> > related.) And can be used anywhere.

> That was my understanding. =A0Thank you for confirming it.

> > Scary. I never had that close a call.

> It's a motivator. =A0Bought two 250' rolls of 12/2 w/G and have been slow=

> replacing 2 wire outlets and wires from the 1940's. =A0Most importantly, =

I've

> moved all the high current devices off the old wiring and left the old tw=

> wire
> outlets to serve things like 2 wire chargers, floor lamps and items that
> never had grounds to begin with and that don't draw lots of current.
> Turns out in an old Cape Cod that doing a rewire from the basement is a l=

> easier than working with the old wires that went up to the attic and then
> down throughout the house. =A0Unfortunately, when we pulled down the poor=

> refinished basement's ceiling and walls, the re-wiring effort was no long=

> the top priority. =A0For one thing there was a huge hole in the cinderblo=

> wall - it looked like someone had started tunneling out. =A0Next time we =

buy a

> house, we'll ask lots more questions if only 1 wall out of 4 in the basem=

ent

> is panelled.

> > The configuration is acceptable in the US except the circuit extends to
> > the basement. (It can extend to dining rooms and some other locations.)

> Yes, I knew when I crossed floors I was probably coloring outside the lin=

es.

> I did it in haste to at least temporarily protect both those areas with G=

FCI

> I also tried to make sure that area was serviced by two different breaker=

> so I could still see if the GFCI tripped and took out the lamps on that
> circuit. =A0It's easy enough to rewire the correct way. =A0Do you know th=

e basis

> for the rule? =A0Is it that one breaker should not service two floors or =

that

> one GFCI can't span floors or both?
> <info about two different compressors starting at the same time snipped>'

> > Producing an "overload" might trip a circuit breaker but won't trip a
> > GFCI. They only look for a current imbalance.

> What worried me is that there may be an underlying small ground current
> leak - perhaps some insulation is degrading - and it only shows when the
> GFCI warms up from carrying a larger than normal current and some capacit=

> or resistor value shifts enough to make the imbalance detection circuitry
> react differently. =A0A while back Smarthome released new Insteon-brand
> switches, and IIRC, they only exhibited flashing problems when the load o=

> the unit was beyond a certain limit. =A0People with chandeliers and 300W
> torchiers ran into serious problems with unwanted flickering and outright
> flashing that users with small lamps (and probably most of Smarthome's be=

> testers did not experience. =A0I note that just to point out that devices=

can

> behave quite differently under a heavy load than they do under a light on=

> > Older GFCIs were more prone to nuisance trip. I kinda forget - I think
> > several people suggested trying a new GFCI.

> Yes, and that's underway as I noted elsewhere. =A0The unit in question is
> perhaps a 25 year old Slater. =A0I will swap it for a 2008 model Leviton.

> > If they indicate a problem there is very likely something wrong. If the=

> > indicate OK the wiring is probably OK. But they can miss problems. In
> > particular, they can not check the the ground is good - they will
> > indicate good for a high resistance connection. Actually the same is
> > true for a high resistance hot or neutral connection, but you will see
> > the problem if you plug in a light.

> No problems with any of the testers so far. =A0Everything checks out. =A0=

I am

> pretty sure that this issue was caused by having other devices on the sam=

> outlet. =A0I'll be switching the fridge over to its own dedicated line la=

ter

> this week and I'll also be switching out the older model Slater GFCI for =

> newer Leviton 20A model. =A0I'm hoping those two changes will eliminate t=

> nuisance tripping. =A0If the problem occured more than once or twice a ye=

ar,

> I'd remove the GFCI entirely, but I'm reluctant to give up the protection=

> ostensibly affords until it proves itself to be too troublesome to mainta=

in.

> >> 25 years of watching This Old House. =A0Despite what many people say,
> >> there isn't an episode where I haven't learned how to do at least one

> thing

> >> better. =A0Tommy Silva is the one I've learned the most from, and Bob =

Villa

> >> the least. =A0Sometimes it's something as simple as using a new blade
> >> every three or four trim cuts on wallpaper or as complicated as chasin=

> down

> >> bizarre problems with hot water heating.

> > I wish they had an electrician as good as the other regulars.

> I agree. =A0Still, they've taught me a lot. =A0I wonder if they deliberat=

ely

> chose not to focus on electrical work because of all the potential danger=

> Thanks for your input, Bud.
> --
> Bobby G.

Hey thanks for the reminder. 'A GFCI not crossing floors'. However I
prefer the idea of a GFCI being in a weather protected environment!

For example: We have an outlet low down outside front door in a rugged
weather resistant box, fed with conduit that runs under the front
step. It's been there some 35+ years and is convenient and useful for
Christmas lights etc.

But would prefer to have the GFCI on it in the basement from which it
is fed! Rather than outside in the weather and beyond that old conduit
under the concrete front step. There is occasioanlly snow build up in
that area.

Welcome any comments/advice. However if necessary (or safer) the
outside outlet might/could be eliminated. TIA

Posted by Robert Green on October 21, 2009, 6:08 pm

news:2fc66247-2712-4d44-a429-

>Hey thanks for the reminder. 'A GFCI not crossing floors'. However I
>prefer the idea of a GFCI being in a weather protected environment!

>For example: We have an outlet low down outside front door in a rugged
>weather resistant box, fed with conduit that runs under the front
>step. It's been there some 35+ years and is convenient and useful for
>Christmas lights etc.

>But would prefer to have the GFCI on it in the basement from which it
>is fed! Rather than outside in the weather and beyond that old conduit
>under the concrete front step. There is occasioanlly snow build up in
>that area.

While I'm *definitely* no code expert, I'd agree with you, out of common
sense, to try to keep the "controlling" GFCI outlet inside and a much
simpler standard outlet outside. That's how I wired my outside outlet. The
GFCI controlling it also runs the radial arm saw and it's mounted inside.
Not sure if that's code, but the likelihood of my operating the saw and
anything else outside at the same time is very remote. The power to the
outlet is also controlled by X-10, so I can turn it on and off from anywhere
in the house.

The GFCI should have a temperature range rating. It could be very possible
that operating it when it's too cold could compromise its protection
capabilities. I'd be more worried that you've got it in a bad place with
regards to potential immersion. When I searched for guidance in the NEC,
all I found was a maximum outlet height limit, which I thought peculiar
since they didn't give a minimum one, which I thought would be more
important.

If I recall my outdoor box, it was set up for a standard duplex outlet and
wouldn't even accommodate a GFCI because they are typically in the Decora
style because of the need to access the "Test" and "Reset" button. Look
outside - the decision to use an indoor GFCI may already have been made for
you! (-:

Then there's the issue of resetting. You may not want to trudge inside and
out to keep resetting the unit. There's a lot to be said for local control
in these cases. Part of the reason I'm rewiring the fridge to its own GFCI
is because I want the reset button right near the protected unit as I have a
"blown out" knee (I think that's the proper medical term) and going up and
down the stairs isn't much fun at the moment.

--
Bobby G.

Posted by ransley on October 15, 2009, 6:51 am

> I've had a GFCI outlet that powers a refrigerator and some kitchen and
> basement outlets trip twice within the last year. =A0I've reset it after =

each

> trip and it seems to go another six months before it trips again.
> What's the best way to determine if this is just a random event or whethe=

> the GFCI is pointing toward a potential shock hazard?
> --
> Bobby G.

Gfci are not for a frige, if they trip the food is ruined, mine
tripped I removed it.

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GFCI Troubleshooting - Page 4