ECN Forum
Posted By: John GFCI's and refrigerators - 06/22/01 09:31 PM
Does anyone know the percentage of homes that use GFCI's with refrigerators? I know the NEC does not recommend GFCI's with a refrigerator appliance. I am looking for a percentage. Thanks!
Posted By: Bill Addiss Re: GFCI's and refrigerators - 06/22/01 10:31 PM
John,

Welcome aboard!
That's one of my personal "things" I'll avoid GFCI protection on Refrigeratios and Freezers whenever possible. No statistics though, sorry. [Linked Image]

Bill
Posted By: sparky Re: GFCI's and refrigerators - 06/22/01 10:46 PM
Hi John.

I know of no statistic, but would wager owners of GFI'ed refrigerators eat out more than most..

[Linked Image]
Posted By: Anonymous Re: GFCI's and refrigerators - 06/22/01 11:26 PM
>I know the NEC does not recommend GFCI's with a refrigerator appliance.
I have run my refrigerator at home from a GFCI for over 7 years (It's daisy chained from the outlet by the sink, so I didn't have an easy alternative, and this is common in old work). The GFCI works. But it has never tripped other than during a test. Even though the fridge is pretty old, once it got through the first day I have not feared that the GFCI might have a false trip.

My best estimation is that good household appliances won't trip a GFCI. If one does, I would suspect that it probably does have a ground fault. I don't have a fluorescent light or any other device in proper repair that will trip a GFCI -- except for my GFCI tester. I don't know how GFCIs got the bad reputation for nuisance tripping.
http://www.epelectric.com/apogee/foe_html/fsgcn.htm


However, anything new I wire, I put the fridge on a circuit by itself without the GFCI.

I think the GFCI is good protection. People have been known to smash the lightbulbs in the refrigerator and a GFCI would protect them from electrocution. Eating out might be more dangerous though.
Posted By: Bill Addiss Re: GFCI's and refrigerators - 06/23/01 01:20 AM
DS,

What concerns me is that it might trip from a power surge or during a storm. If someone is away, or in the case of the deep freeze in the Basement that no one opens for weeks it could be a real downer. If you've had no problem for 7 years that still doesn't mean that it can't happen tomorrow.

Bill
Posted By: Anonymous Re: GFCI's and refrigerators - 06/23/01 02:16 AM
>What concerns me is that it might trip from a power surge or during a storm.

It might. But could you give a scenario of how that could theoretically be possible?

In other words, give me a scenario which will create a 5 milliamp current imbalance between UGC and GC, or a surge pulse that will create a magnetic field of sufficient strength and duration to be sensed as a ground fault.

I'm not saying that such a scenario doesn't exist. But I personally haven't been able dream one up. And no one else has ever offered me one either that wasn't actually a ground fault.

>If someone is away, or in the case of the deep freeze in the basement that no one opens for weeks it could be a real downer.
I totally agree, and I don't and probably would not use a GFCI for a freezer.

>If you've had no problem for 7 years that still doesn't mean that it can't happen tomorrow.
There are a lot of things that could happen tomorrow. But I can't think of a scenario in which the GFCI will trip that was not a ground fault.

I forgot to mention before, I used to run my water pump off a GFCI and it never tripped either. (Later I changed it to 220 V and gave up the GFCI protection.)

My experience has been that only ground faults trip GFCIs.
Posted By: Bill Addiss Re: GFCI's and refrigerators - 06/23/01 05:31 AM
DS,

Check here (at the end) for a possible explanation?
http://www.codecheck.com/gfci_principal.htm

Bill

[This message has been edited by Bill Addiss (edited 06-23-2001).]
Posted By: Anonymous Re: GFCI's and refrigerators - 06/23/01 06:05 AM
I had found this page when I searched for 'nuisance tripping'.

All it says is:
"Highly inductive loads like large motors or even fluorescent lamps or fixtures on the same circuit can cause nuisance tripping of GFCIs which needless to say is not desirable for something like a refrigerator."

But to me, that is a claim.

It is not backed up with any empirical data, nor any hypothesis as to why this might occur, nor any evidence that the circuits in question were tested and proven free of ground faults.

Since ground faults are common in the mentioned devices, I require that ground faults be ruled out.

In fact, many older fluorescent lamps wouldn't start unless the EGC was connected. I consider those bad appliances.

Many motors have leaks from the brushes to the case via copper dust, carbon dust, or common dust. Leaks may also occur from dirty or corroded terminals or dirt elsewhere such as the thermal overload, capacitor, or reset switch.

Since such a fault can be dependent on temperature and vibration, the fault may occur intermittently. But it is still a ground fault.

I haven't seen any theory on how an inductive load can create a current imbalance between GC and UGC of 5 mA or more.
Posted By: sparky Re: GFCI's and refrigerators - 06/23/01 09:58 AM
It is not backed up with any empirical data


not exactly your strong point either!
Posted By: Bill Addiss Re: GFCI's and refrigerators - 06/23/01 12:28 PM
DS,

There was also a section about Lightning:
Quote
Is GFCI tripping caused by electrical storms normal ? Are my GFCI breakers too sensitive ? Is there any way to modify the circuits to avoid this?"

This doesn't surprise me. Long runs of cable will be sensitive to the EM fields created by nearby lightning strikes. Those cables probably have 3 parallel wires: H, N, G. The lightning will induce currents in all three which would normally not be a problem as long as H and N are equal. However, I can see this not being the case since there will be switches in the Hot but not the Neutral so currents could easily unbalance.

For the record, I am not endorsing the above comments, only pointing out that they were there.

I have no reason to disbelieve the claims or "theories" of nuisance tripping. Isn't a Refrigerator a Grounded Appliance and should therefore trip a breaker if the frame becomes energized? Why the argument about removing it from the GFCI?

From working in the field I have seen many times where a GFCI has tripped for no apparent reason at the same time as a Lightning storm or during some unusual power event. Take that as you wish. If you want to ignore what seems to be the general consensus that's up to you. I would suggest that you start a topic under the Theory section if you want to delve into it further.

Bill
Posted By: electure Re: GFCI's and refrigerators - 06/23/01 03:12 PM
DSpark
The fact that you have a GFCI powering your OWN reefer at home doesn't make it a good idea to install such for customers (remember that you're the guy that claims to have 2 lights wired in series, would you do that in somebody else's place?). I would prefer not to have a call back every time a client buys a new refrig. (What do you tell them, that they should return their new $2000 Amana because it tripped your $7 GFCI that's not required anyway? Most people would just think you didn't do the job right)

[This message has been edited by electure (edited 06-23-2001).]
Posted By: Anonymous Re: GFCI's and refrigerators - 06/23/01 06:36 PM
>The fact that you have a GFCI powering your OWN reefer at home doesn't make it a good idea to install such for customers

And if you take the time to read my comments above, you would see that I don't.


>(remember that you're the guy that claims to have 2 lights wired in series, would you do that in somebody else's place?).

Don't be so rude. Those light were installed that way long before I was even born.

>I would prefer not to have a call back every time a client buys a new refrig. (What do you tell them, that they should return their new $2000 Amana because it tripped your $7 GFCI that's not required anyway?
Have you ever seen a new appliance without a ground fault that trips a GFCI?
Posted By: Anonymous Re: GFCI's and refrigerators - 06/23/01 06:39 PM
>not exactly your strong point either!

What do you mean? I have lots of empirical data. I've run a water pump and a fridge off a GFCI.

I do regularly put in GFCIs for window air conditioners.

I have never have a problem. To me that is a lot of empirical evidence.

However, there is this old wives tale about nuisance tripping. Not a single person has come forward with an actual example. People just believe that it happens. I suggest that it happens only with leaky devices.
Posted By: Anonymous Re: GFCI's and refrigerators - 06/23/01 07:00 PM
>I have no reason to disbelieve the claims or "theories" of nuisance tripping.
I have little reason to believe it. It is not much of a theory. A theory would explain how it happens with a real equation. Saying that hot and neutral could easily have an imbalance because of switches in the hot does not explain much if there are no switches downstream from the GFCI.

However, I have been considering this theory and I'll work on it when I get a chance.

>Isn't a Refrigerator a Grounded Appliance and should therefore trip a breaker if the frame becomes energized?
Yes. But it your child breaks the light bulb and sticks his finger in it, do you want to wait for 50 amps to flow before the breaker trips?


>Why the argument about removing it from the GFCI?
Where was this?

>From working in the field I have seen many times where a GFCI has tripped for no apparent reason at the same time as a lightning storm or during some unusual power event. Take that as you wish.

I haven't seen this. Did you test all of the equipment on the circuit to insure that it was free of ground faults?

>If you want to ignore what seems to be the general consensus that's up to you.
It's not a matter of ignoring it. I don't ignore it. I caution people that GFCIs are rumored to have nuisance tripping. I don't normally install GFCIs for refrigerators. I would recommend against using a GFCI for a freezer.

>I would suggest that you start a topic under the Theory section if you want to delve into it further.
Is that an order?

I can quite readily explain why lightning exposes existing ground faults. A leak of 3 mA at 120 V readily becomes a leak of 6 mA or more during 300 V surge.

Pinched insulation may not leak at 150 V but does breakdown at 300 V.

Copper dust may not leak much at 150 V. But at 300 V, it arcs over and makes a good ground fault.
Posted By: sparky Re: GFCI's and refrigerators - 06/23/01 07:21 PM
To me that is a lot of empirical evidence

I suppose you are correct,in that you are king of your empire!

Why then don't you utilize 215-9 ??

Would this not be economically correct for your abudance of GFI desires?
Posted By: Bill Addiss Re: GFCI's and refrigerators - 06/23/01 07:22 PM
DS,

I am suggesting that if you want to discuss possibilities regarding theory there is an area set aside for it. This is a Code forum and Questions and Answers here are largely around that subject.

Quote

>What concerns me is that it might trip from a power surge or during a storm.
It might. But could you give a scenario of how that could theoretically be possible?

Didn't you write this?
"It might" - that sounds like you are allowing the possibility, what changed? Why is the burden of proof on us?


BTW, you said Twice that you run your Refrigerator off a GFCI.

[This message has been edited by Bill Addiss (edited 06-23-2001).]
Posted By: Anonymous Re: GFCI's and refrigerators - 06/23/01 08:47 PM
>"It might" - that sounds like you are allowing the possibility, what changed?
Nothing changed. I will always allow for the possibility. It is impossible to rule out everything.

> Why is the burden of proof on us?
If I said that GFCIs nuisance trip because pixies come along at night and like the clicking noise made when they push the test button, would you believe that?

I mean by default I don't believe something unless it seems believable. You and I just have different standards for what we consider believable about causes of nuisance tripping.

I don't know for an absolute fact that pixies don't like tripping GFCIs. But I consider the odds so remote as not to be a concern.

The ground faults are really caused by sparkling pixie dust which then vanishes.

>you said Twice that you run your Refrigerator off a GFCI.
That is correct. It has been running fine that way for over 7 years. Would you like for me to say it again?

When I said freezer, I was talking about a deep freeze or a chest freezer, etc., not a refrigerator. Is that what you are getting at?
Posted By: Anonymous Re: GFCI's and refrigerators - 06/23/01 09:17 PM
>Why then don't you utilize 215-9 ??

Are you asking why I don't just use GFCI breakers for everything?

Two major disadvantages are that one has to go to the panel to test or reset them.

Considering how rarely people test a GFCI when it's right there, I can't imagine them going to the panel to test them.

My habit with rarely used GFCI outlets is to leave them tripped when not in use. That reminds me or the next person to test before using.

I don't get what you are saying about economics either. But yes, a GFCI outlet is usually cheaper than a GFCI breaker.
Posted By: Bill Addiss Re: GFCI's and refrigerators - 06/23/01 09:40 PM
DS,

You're not making much sense and can't even seem to agree with your own comments.
Posted By: Anonymous Re: GFCI's and refrigerators - 06/23/01 10:18 PM
>You're not making much sense and can't even seem to agree with your own comments.

If you think that any of my comments don't agree, try to post them side by side.

I think you just think that I said something that I never said.
Posted By: Anonymous Re: GFCI's and refrigerators - 06/23/01 10:21 PM
>I'll avoid GFCI protection on Refrigeratios and Freezers whenever possible.

And when you feel that it is not possible, do you "ignore what seems to be the general consensus"?
Posted By: Redsy Re: GFCI's and refrigerators - 06/23/01 10:24 PM
It seems that this is a judgment call.However, the majority seem to agree to omit GFCI on refrig where possible. As far as theory v. empirical data, what one chooses to believe is their own personal right aftre all, even scientific observations are often skewed by the personal expectations and beliefs of the observer(can you say creation v.evolution?). And,just because someone hasn't experienced something it doesn't mean it doesn't exist. The question seems to have been answered. Next topic, please. (Boy, I used to enjoy this site!).
Posted By: Bill Addiss Re: GFCI's and refrigerators - 06/23/01 10:34 PM
Redsy,

I Agree,

Bill
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