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Commercial refrigerator malfunctioning on gfi.

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hillbilly1

Senior Member
Location
North Georgia mountains
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Owner/electrical contractor
Just had a customer call and say their commercial refrigerator was malfunctioning, shutting off, circuit board resetting. He called the manufacturer, and they asked if it was on a gfi circuit, which it is. They said he needed some sort of filter, because their product doesn’t like gfi’s. Doesn’t trip the outlet, just screws up the electronics in the refrigerator. Just a heads up if anybody else has came across this problem. Manufacture said the problems started when the code requirements changed.
 
mtnelect

mtnelect

HVAC & Electrical Contractor
Location
Southern California
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Contractor, C10 & C20 - Semi Retired
That is why the NFPA issued TIA No. 1653.
 

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  • Daikin - Installation Manual #2.pdf
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  • TIA Log No. 1653, HVAC GFCI, 05-27-2022.pdf
    652.6 KB · Views: 15
Jraef

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
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Electrical Engineer
I’ll call BS… yes, a load with certain characteristics may cause the GFCI to TRIP, but the GFCI has no measurable effect on the power going through it. All it does is pass the power through a CT, that could not possibly cause a controller to shut down. They are clutching at straws.

Doesn’t trip the outlet, just screws up the electronics in the refrigerator.
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The TIA would be related to nuisance tripping of the GFCI, not the GFCI causing something else to trip.
 
don_resqcapt19

don_resqcapt19

Moderator
Staff member
Location
Illinois
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retired electrician
hillbilly1 said:
Just had a customer call and say their commercial refrigerator was malfunctioning, shutting off, circuit board resetting. He called the manufacturer, and they asked if it was on a gfi circuit, which it is. They said he needed some sort of filter, because their product doesn’t like gfi’s. Doesn’t trip the outlet, just screws up the electronics in the refrigerator. Just a heads up if anybody else has came across this problem. Manufacture said the problems started when the code requirements changed.
Click to expand...
Love to see the engineering explanation for that. There is nothing in a GFCI that could do that as far as I know.
 
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hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
Yeah, I will find out next week. It’s a commercial kitchen at a residence, they do have a mini split in that same panel, maybe the harmonics from it. It’s some off brand refrigerator.
 
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winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
I've grasped a straw which might be relevant.

In addition to the residual current detection, GFCIs are also required to detect neutral to ground (grounded to ground) faults. The circuitry for detecting these faults can induce high frequency (8 kHz or so) currents to flow in the neutral and ground.

If there is some leakage from neutral to ground, not enough to trip the GFCI, there might be high frequency imposed on the neutral and EGC. This could then interfere with any low voltage, ground referenced, communications or sensor wiring.

The GFCI never trips, but the equipment malfunctions.

See
https://www.powerelectronictips.com/teardown-leviton-ground-fault-circuit-interrupter/
and also see starting at the second paragraph of the right column on page 6:

The ground to neutral fault detection involves a feedback loop that includes the neutral and ground, and this feedback loop causes an oscillation at 8kHz. If I understand this correctly, the 8kHz has to show up in the feedback loop wiring.

-Jon
 
hbiss

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
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EC
winnie said:
I've grasped a straw which might be relevant.

In addition to the residual current detection, GFCIs are also required to detect neutral to ground (grounded to ground) faults. The circuitry for detecting these faults can induce high frequency (8 kHz or so) currents to flow in the neutral and ground.

If there is some leakage from neutral to ground, not enough to trip the GFCI, there might be high frequency imposed on the neutral and EGC. This could then interfere with any low voltage, ground referenced, communications or sensor wiring.

The GFCI never trips, but the equipment malfunctions.

See
https://www.powerelectronictips.com/teardown-leviton-ground-fault-circuit-interrupter/
and also see starting at the second paragraph of the right column on page 6:

The ground to neutral fault detection involves a feedback loop that includes the neutral and ground, and this feedback loop causes an oscillation at 8kHz. If I understand this correctly, the 8kHz has to show up in the feedback loop wiring.

-Jon
Click to expand...

Ok. So, if that's the case don't you think it should be on the refrigerator manufacturer to provide filtering to eliminate that problem? They can't claim that it's a commercial unit and wouldn't be subject to GFCIs in a commercial setting anymore.

-Hal
 
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winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
I'd agree that the refrigerator manufacturer should provide the necessary filtering.

Also if my suggestion is correct, then there has to be some ground to neutral leakage which is also a problem.

I have mixed feelings on the expansion of GFCI requirements, but now is not the time for an essay :)

-Jon
 
H

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
Little Bill said:
Commercial kitchen at a residence, or commercial refrigerator at a residence?
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It’s at a residence, but it is a full blown commercial kitchen. It’s a whole room built off the house. Kinda like the old time hot kitchens! The owners wife ran a restaurant for many years. I’ve got 16 countertop circuits in there!
 
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