ECN Forum Forums Code Related Discussion NEC & other Code issues article 210.8(B)(2)

right on reno! I've seen other places where the code states something like: "in accordance with..." followed by the section referred, but 210.8(B)(2) is a very poorly written code.
given the discussions I can say that I don't know why, with exacting precision, a safely functioning 'frige will trip a gfci, but I know from experience that they very often do (there is an exception for dedicated appliances in dwellings - 210.8(A)(2) ex.2) but the ahj, correctly, said it doesn't apply for commercial kitchens). Reno hit it on the head - there are no inclusions or exceptions but he found the conflict that should be addressed in that code.

Yes, that is correct, I am very much aware of how a GFCI functions.



To the GFCI this capacitor charging is just another load, no different than an incandescent lamp, vacuum cleaner or battery charger.

It is imposable for a capacitor (or any electrical load) to as you put it 'draw current without returning it' .

The charging load of the capacitor will be equal across the lines connected to it.



Glad to have you aboard.

Sorry, but I disagree. 110 IS an article in the NEC. The appliance is UL listed, so 110.3(A) does not come into play.

I named one brand because that's the one I have the sheet on. We do not know the brands involved, and I would not be surprised if a similar instruction came with many other makes as well.

Now, if you're saying that it's up to the restaurant to document that the equipment is intended for use in a commercial kitchen, and that such an instruction exists .... I can agree with that.

Considering that Dacor is an 'upscale' brand, justifying its' high price with claims of quality, I believe it is very possible that commercial equipment has a similar stipulation.

Assuming that the instructions say "no GFCI," we most certainly have a conflict within the NEC.

Samurai, as I mentioned before .... code rules aside ... you really ought not be having nuisance tripping with refrigerators anymore.

The electronics within an appliance, as well as the effect a starting motor has on "power factor," have the effect of changing the time at which things happen.
Simply put, a simple resistance load, when put on an oscilloscope, will show both the volts and the amps as sine waves in time with each other. Any other load ... be it capacitor, inductor, whatever ... will change that timing, and may even change the shape of the sine waves.
Since a GFI works by comparing what goes 'in' with what comes 'out,' such a change in the waveform could be interpreted as a fault. It is claimed that internal design changes in the GFCI's make them more tolerant of this sort of thing - so no more nuisance tripping.

I must confess that every time I have seen a fridge trip a GFCI, or had reports of shocks, there were two things present: an exceptionally good ground path, and an old fridge. Replacing the old fridge with another one solved the problem in each instance. Fridges DO wear out, and current leakage seems to be one of the early symptoms.

GFCI's are ordinarily set at 5mA for "personnel protection." This is well below the 'usual' fatal level - more akin to an 'annoying shock.' GFCI's are made set to different levels, but that is perhaps outside the scope of this thread. Such other settings are for different purposes, and perhaps we ought not "fix" problems by using a 'bigger fuse."

It is not an NEC or UL conflict.

The conflict is with the selection of incorrect equipment to use in a commercial kitchen regardless if it is listed as a 'Commercial refrigerator' if the manufacturer requires 'no GFCI' it is the wrong unit for a commercial kitchen....assuming it's 15 or 20 amp 125 volt cord and plug connected.

Whoever picks the equipment for a commercial kitchen must pick equipment that will allow compliance with any and all codes.

Do you have some references for that?

The fact that 5 ma may not kill anyone has no bearing on any of what we should be doing out in the field.

Of course the set point of a GFCI was chosen to be under the 'normal fatal level' they would be pointless if that was not the case.

However when we respond to a GFCI tripping call we have no way at all of knowing if it tripped at 8 milli-amps or 8 amps.

Bob, I am having some trouble following your reasoning.

First of all, I've seen plenty of UL Standards, and they all reference the NEC. I am not aware of UL ever listing something that is inherently in conflict with the NEC.

110.3A says that equipment be 'suitable.' Now, perhaps I'm being too literal, but if the catalog and UL tag say "Commercial kitchen equipment," I would think it would be suitable for use in a commercial kitchen.

IF that same appliance had instructions that said 'no GFCI,' then 110.3B would be enforceable. Which, in this case, puts us squarely in conflict with the much newer 210.8 rule.

Sure looks like a code conflict to me.

I think we are putting too much credence in what a translater makes of the original Chinese instructions. I understand 110.3 but I also understand the people who write instructions these days have English as a second language. Add a couple lawyers to the mix and instructions ain't what they used to be.

Bob, I agree entirely as to fault levels. Just about every basic electrical text will have some sort of chart (or table) of fault levels. Most of these don't reach 'certainly fatal' until well over 50mA. Values under 10mA are described as various levels of shock.
If nothing else, it's safe to say that the 5mA level wasn't pulled out of thin air.

NOW - and I think this is what you're getting at ... a person CAN die from a much smaller shock, if the conditions are right. The level of shock felt will even vary by individual.

You will note that I did elaborate, and discourage the idea if using a higher setting.

Reno, sorry but it doesn't matter if this is a high end or low end unit, if it can not be used with an NEC wiring method it is the wrong piece of equipment as Bob points out.

Just because somebody wants to buy something that is not intended for the application doesn't trump codes.

Roger