GFCI Troubleshooting

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ransley wrote:

Commercial kitchens require plug-in refrigeration (15/20A 120V) to be GFCI protected.
The exceptions to GFCI requirements that were in the NEC have virtually all been removed. That includes a garage receptacle behind a refrigerator.
The arguments were: "The permitted leakage current for typical cord and plug connected equipment is 0.5 ma. The trip range for GFCI protective devices is 4-6 ma. For this utilization equipment to trip the GFCI device, it would have 8 to 12 times the leakage current permitted by the product standard." "The present generation of GFCI devices do not have the problems of 'nuisance tripping' that plagued the earlier devices."
RBM and John have good advice.
--
bud--

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wrote:

each
whether
Sorry I missed this and a few others on the first read through. New newserver.
That's a good point about current leakage rates. If the unit still trips with nothing else on the circuit AND a new model GFCI in place, then I am going to begin checking out the refrigerator with an ammeter* to see if there really is a current leak. At that point I'd be willing to believe it's not simply a nuisance trip, but an indication of a problem. Hopefully I'll remember to switch the fridge to a non-GFCI outlet when we're away. If there's a ground fault when no one is home, that's not as bad as a meltdown of all our food.
*(Why that spelling and not ampmeter, I've always wondered?)
-- Bobby G.
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Good question but how/why do many other units get adopted/used. Is not 'Volt' named after the researcher Volta? Another example is the Bel (or more commonly the Deci-bel = one tenth of a Bel). Or more commonly and colloquially as Dbs. ("dee-bees"). Named after Alexander Graham Bell! I think 'watt' and 'ohm' are unshortened? Just a thought.
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news:b38c0972-f220-46a1-8139-
<stuff snipped>

How about that poor CPS abbreviation, getting sacked and replaced buy Hz. I can just hear it gloating: "Hertz, donut!"
It sounded funnier rattling around in my brain, I swear! - I was going to say it must have stung like a hit in the family joules . . .
1000 aches = kilohurtz What is it that's black, charred and smouldering and hangs from a light socket? An DIY electrician trying to change a light bulb!
Diode - What everyone hopes they'll do
Somebody, pull the plug on me!
Who's old enough here to remember that TV show with the meter, "Queen Faraday?"
The problem with bad electrical puns is that anyone conduit.
1012 bulls = 1 terabull - what these puns are!
100 buckets of bits on the buss, 100 buckets of bits, Take one down, short it to ground, 99 buckets of bits on the buss.
OK, I'm tapped, I've run out of Gauss.
-- Bobby G.
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On Wed, 21 Oct 2009 03:56:32 -0400, "Robert Green"

I have investigated a couple of these old refrigerators that trip GFCIs and they were all bad. Most had internal shorts in the compressor. I suspect that is why they use more power as they age and why the freon has a burnt smell when you cut open the line. If you put a scope with a current probe on the grounding conductor you see spikes. I bet there is a mini thunderstorm going on inside that compressor. Eventually this can get bad enough to trip the breaker but if the short is closer to the neutral end of the winding it might run like this forever. The only real danger to the user is if the ground has a high impedance and some voltage gets imposed on the case.
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<stuff snipped>

I hear you, and I am here trying to figure out what the various risks and trade-offs are. Given the choice of taking a lethal shock or a freezer full of spoiled food, I'll take the spoiled food every time. (-:
I can take some serious precautions to prevent nuisance tripping like a dedicated line and a late-model GFCI. I'm also building a home automation remote warning system using HomeVision that calls my cellphone if the fridge goes outside of its temperature range or the alarm system detects a break in. I'm hoping to eventually be able to answer the door intercom remotely by having the home automation controller ring my cell whenever someone presses the doorbell when I'm not home. It will also call if the basement floods, the house goes too hot or cold, etc.
I may even decide to add a second, non-GFCI outlet so that if we're away overnight or longer I can switch the fridge from a GFCI outlet to a standard one. I've had nuisance trips, but they've been with a very old Slater 1st generation GFCI on a non-dedicated circuit. Changing to a new GFCI and a dedicated line should reduce those nuisance trips to near zero. Well, that's the plan. Hopefully I won't have to post a follow-up that says "Mark was right and I've got a freezer full of chum."
Thanks for your input,
-- Bobby G.
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It doesn't take much of a ground fault to cause the device to trip. It's not likely that you'll find it, if it only happens every six months. If the gfci device is old, you may want to replace it with a newer model, which should be more reliable

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*Just replace the GFCI receptacle. It the easiest and fastest way. The newer models are less prone to nuisance tripping. If I had to bet I would say the problem is with the refrigerator. Older models had lower standards for ground fault leakage. However you do have your circuits spread out too thin. The code requires two 20 amp circuits for kitchen receptacles and nothing else to be connected to those circuits. You should separate the basement from the kitchen.
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Suggestion? If you can wire the outlet into which the fridge is plugged from the 'input' side of the GFCI rather than 'through' the GFCI? As others have said, GFCI not recommended for fridge or freezer. (Or in fact many electric motor circuits). BTW while the GFCI are designed to protect say a human from leakage from a faulty appliance to ground, such as leaky electric lawn mower or electric hedge trimmer etc. the name IS something of a misnomer. The GFCI operates when there is an 'unbalance' between neutral and live current. Older appliances or even new ones may have slight leakage, but after all they are grounded and/or may have sufficient unbalance as the motor starts to unbalance the two currents momentarily.
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Like others said, pull another branch circuit non-gfci for the fridge.
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This is slightly off-topic for this thread, but I've always considered the test button on a GFCI somewhat of a conundrum.
Here's my logic:
They say to test a GFCI once a month. Why? To see if the GFCI is still working, right?
OK, but all the tester knows is whether or not the GFCI was or was not working at that particular point in time. It could go bad instantly afterwards - in fact, that test could have been the thing that ruined it. How would you know? All you could do is test it again, but then all you would know is whether the GFCI was or was not working at that particular point in time.
In other words, testing a GFCI gives you no assurance that the GFCI will operate properly when required. Yes, a failed test will tell you that it won't work if required, but a passed test won't tell you that it will.
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DerbyDad03 wrote:

All medical tests (glaucoma, cholesterol, cancer, ...) are useless. They don't tell you if you will have a problem tomorrow.
--
bud--

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"Useless" is your word, not mine, and given the examples you chose, also wrong.
Similar to testing a GFCI, medical tests can certainly tell you if something needs to be done *right now* - swap the known bad GFCI for a hopefully good one, begin a medication regimen or diet change, etc.
In addition, certain medical tests can signal an upcoming problem. For example, higher than normal glaucoma readings might signify a need more frequent testing than a normal reading would. Higher than normal cholesterol numbers might indicate the need for a change in diet or even medication.
While a normal reading will certainly not mean that you will never get sick, statistics show that if you have a normal reading and get tested on a regular basis, problems can be usually be caught before they become life (or sight) threatening.
However, a GFCI test doesn't have a "range". It's either going to pass or fail. Failure tells you something useful...passing means nothing. Failure tells you that you should change it right nowpassing simply means it probably would have worked if it was needed in the past.
Thats why I used the word conundrum, not useless.
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news:ccbb7393-f6bf-46a3-
<stuff snipped>
<However, a GFCI test doesn't have a "range". It's either going to pass or fail. Failure tells you something useful...passing means nothing. Failure tells you that you should change it right nowpassing simply means it probably would have worked if it was needed in the past.>
While the tester is certainly a binary, pass-fail event, nuisance tripping may actually be the GFCI detecting a growing irregularity of some kind. Cords fray slowly and corrosion is no jack rabbit, either. That's my "current" conundrum - deciding whether the nuisance tripping is really just a spurious event or a signal that there's an unhealthy interaction between electrical components that should be run to ground. I guess I've worried myself enough to stop grousing about it and read up about detecting current leaks in appliances.
As a X-10 home automation user, I've learned the the household wiring is truly a network. Plug-in devices can interact very strongly with each other in some very annoying ways. In my case the bad interactions appear as ground loops and degraded X-10 signal strength.
-- Bobby G.
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Take the fridge off the gfci. If you're lucky you can just move it down one outlet and cover the remaining outlets.
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On Thu, 15 Oct 2009 02:18:16 -0400, "Robert Green"

A GFCI doesn't make sense with refrigeration which I believe is an exception. Purchase an electrical outlet tester (about $15) and/or replace the GFCI.
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