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#77560 - 06/22/01 02:31 PM GFCI's and refrigerators
John Offline
Junior Member

Registered: 06/22/01
Posts: 1
Loc: Evansville
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!

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#77561 - 06/22/01 03:31 PM Re: GFCI's and refrigerators
Bill Addiss Offline
Member

Registered: 10/07/00
Posts: 4196
Loc: NY, USA
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.

Bill

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#77562 - 06/22/01 03:46 PM Re: GFCI's and refrigerators
sparky Offline
Member

Registered: 10/18/00
Posts: 5545
Hi John.

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


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#77563 - 06/22/01 04:26 PM Re: GFCI's and refrigerators
Anonymous
Unregistered


>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.

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#77564 - 06/22/01 06:20 PM Re: GFCI's and refrigerators
Bill Addiss Offline
Member

Registered: 10/07/00
Posts: 4196
Loc: NY, USA
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

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#77565 - 06/22/01 07:16 PM Re: GFCI's and refrigerators
Anonymous
Unregistered


>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.

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#77566 - 06/22/01 10:31 PM Re: GFCI's and refrigerators
Bill Addiss Offline
Member

Registered: 10/07/00
Posts: 4196
Loc: NY, USA
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).]

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#77567 - 06/22/01 11:05 PM Re: GFCI's and refrigerators
Anonymous
Unregistered


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.

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#77568 - 06/23/01 02:58 AM Re: GFCI's and refrigerators
sparky Offline
Member

Registered: 10/18/00
Posts: 5545
It is not backed up with any empirical data


not exactly your strong point either!

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#77569 - 06/23/01 05:28 AM Re: GFCI's and refrigerators
Bill Addiss Offline
Member

Registered: 10/07/00
Posts: 4196
Loc: NY, USA
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

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