Vending Machine GFCIs

[Paul Sweet]

I understand that NEC 422.51 requires new or replacement cord-connected vending machines to have a GFCI in the cord. 2020 NEC 210.8(D)(5) requires receptacles for vending machines to have GFCI protection and for the GFCI to be readily accessible, so it requires a GFCI breaker if the receptacle is behind the vending machine.

Does having a GFCI in the cord wired in series with a GFCI breaker increase the chances of problems such as nuisance tripping?

 

[BN4537]

I understand that NEC 422.51 requires new or replacement cord-connected vending machines to have a GFCI in the cord.

I don't have a 422.51 in my 2020 NEC or my 2023 NEC, but I found it on UpCodes in the Florida version of the NEC. Looks like it was inserted by the Floridians...

Standard NEC you just need to GFCI the circuit.

Does having a GFCI in the cord wired in series with a GFCI breaker increase the chances of problems such as nuisance tripping?

Yes, probably. GFCIs vary from manufacturer to manufacturer, and unit to unit, so it is likely stuff would trip one that would not trip the other. Then you have to figure out which one tripped. Not really good practice in general to daisy chain GFCI's for that reason.

 

[wwhitney]

Does having a GFCI in the cord wired in series with a GFCI breaker increase the chances of problems such as nuisance tripping?

No. It just means that if there is a ground fault in excess of the GFCI trip threshold (4-6 ma), you'll have to check both GFCIs to see which one(s) to reset, as either or both could trip.

Cheers, Wayne

 

[BN4537]

If the GFCI's are tripping because a ground fault or anything else addressed by the current UL standard, yes. If they are tripping because of high-frequency leakage current or "noise", like with ranges and other appliances, or any other weird phenomenon, some are likely to be better than the others. The algorithms used by each manufacturer are proprietary, so they vary widely on anything that is not nailed down in the UL standard.

https://collateral-library-producti...y_Spectrum_for_120_V_Household_Appliances.pdf

My point is that there are likely to be scenarios where one of the GFCIs would not have nuisance tripped, but the other one did nuisance trip.

 

[Paul Sweet]

Thanks for everyone's responses and for the link.

It looks like 422.51 disappeared in the 2017 edition.

I'll go ahead and specify GFCI breaker protection for receptacles serving vending machines. If nuisance tripping does occur the breaker can be changed to a non-GFCI breaker as long as the vending machine has an integral readily accessible GFCI.

 

[BN4537]

It looks like 422.51 disappeared in the 2017 edition.

Ah, that explains it. I thought it was a new section invented by Florida Man, lol.

 

[jar546]

Ah, that explains it. I thought it was a new section invented by Florida Man, lol.