(GFCI requirementsfor personnel protection)
"commercial and institutional kitchens - for the purposes of this section,[sic] a kitchen is an area with a sink and permanent facilities for food preparation and cooking"
DUH! DUH DUH! there are no exceptions for refrigeration equipment (110v coolers etc.)
or steam/chiller tables - because of the capacitors in many refs and im guessing inductive reactance in heating appliances a good, working, safe, functional piece of equipment of these types will trip gfci receptacles. I talked with P&S legrand tech support to ask if they had come up with some kind of 'smart' gfci to address the tripping issues with the stuff the only answer he had was to install grade B gfci (circuit breaker) protection which he rightly said defeats the purpose of the personnel protection.(honestly I was unaware that the breakers had a higher trip threshhold until he advised me)
this code repeatedly stabs itself in the throat (I'd be honored to serve as a consultant to a commercial kitchen equipment manufacturer - because I think I have the answer aside from a well needed exception or demanding a proper fix be applied)
I imagine a similar thread is buried somewhere but I havent heard anything about the '08 code addressing this.

Well, first of all the P&S tech support is giving bad information, a class B device is not for personell protection per the NEC definition of GFCI



The manufacturers of the equipment should produce products that will work properly.

I have heard the "refridgerator trips GFCI's" argument many times and I don't buy it.

We install GFCI's on construction sites that run everthing from simple drill motors to Jack hammers and even job site refridgerators.

Commercial refridgerators can be connected to alarm systems with a dialer to notify a few people of lost power if necessary.

Roger

I agree whole heartedly with Roger.

The thing to remember is if there is enough leakage current to to trip the GFCI there is also enough leakage current to kill someone if the appliance loses it's EGC.

The reason this requirement is in the code as someone in a kitchen was killed from (if I recall correctly) contact with a commercial refrigerator that had lost the EGC continuity.

I got into this at my wife's new place (in a country club kitchen). It turns out they hose down commercial kitchens as part of the normal cleaning process and that is one reason why they trip GFCIs. Perhaps commercial kitchen equipment should be sealed against water intrusion better but it is not the compressor starting that trips the GFCI ... unless it is shorted interrnally.

Yeah wash downs can be a problem. I work in a lot of super markets and even the use of 'Marine Grade' cord caps and outlets in wash down areas like the meat room, deli, prepared foods areas does not stop wash downs from causing problems.

For refrigerators the 2002 Handbook claims a common cause of refrigerators tripping the GFCIs is electric defrosting elements in the units.

This to me makes much more sense then the compressor tripping it. GFCIs can supply motor loads without a problem.

I've been enforcing this for the past two years with no problems. Except to keep the electricians up to date that it is required.
Most of the chain resturants use the same guys year after year and just because they always did it one way they are slow to pick up on the changes. This is complicated by jurisdictions that are still using older Codes.
The big food coolers and freezer are hard wired no GFI required. The smaller plug in units should be emptied daily with the food moved to the bigger ones. For a church or other small user the kitchen outlets could have a simple night light plugged in to show when it is tripped, as well as the indicator light.
Compared to in use covers and tamperproof receptacles this rule makes sense.
Alan

A gfci works like an amprobe- as long as the total flow = 0 when "probing" line and neutral together the gfci assumes safe functioning. capacitors act a little like a battery where they draw current without returning it the gfci reads current leaving and not returning and "detects" a fault.
I'm sure the capacitance value has a strong bearing on whether or how often the gfci is fooled into thinking the appliance has faulted.
A gfci isn't an intelligent object it's very good for protecting people from shock conditions but cant distinguish shock condition from normal function.
I havent heard of the hosedown approach like washing a boatdeck but it wouldn't surprise me
thanks for the input guys, I'm really enjoying this site

A few years ago, the testing standards for GFI's was changed. One result of this change was that new GFI's are much more resistant to nuisance tripping than earlier models. They also require a good neutral path, or the GFI will trip.

That said, there IS a conflict within the NEC on the issue. While the section quoted has no exceptions noted, section 110.3(B) also has no exceptions noted where it says 'equipment shall be installed according to instructions.' (slight paraphrase for clarity).

I am looking at the instructions provided by Dacor, a premiun brand of refrigerator. Their sheet states "Your Dacor Built-in refrigerator is equipped with a .... power cord, which must be plugged into a 3-prong grounding type non-GFCI wall receptacle."

So, it seems that it's not a question of whether you violate the NEC; it's a question of which section is violated!

Since the 'law' here is contradictory, I can only fall back on the principle that any ambiguity in a contract be construed against the party that wrote it.
In this case, that would mean that the GFCI rull cannot be enforced against refrigerators in commercial kitchens.

I doubt capacitance has anything to do with it. Reactive circuits can cause current to lag behind voltage but the total current in the circuit is equal at any point in time. (according to Mr Kirchoff). The amount going in always equals the amounty coming out right then. The GFCI just senses that it is not all coming out through the circuit conductors. That is a leak somewhere.

Bob, I doubt marine grade will really help you that much on the GFCI problem. That really just means the metals are less corrosive (usually stainless).
Maybe if it was NEMA 6R?

Reno, this has no bearing on any article in the NEC. It is very simple, this particular brand of refrigerator can not be used in a commercial kitchen, there is no conflict at all.

When they get to the point they want it to work in NEC compliant commercial kitchens they will remove that wording from the instructions and make the units work with Class A GFCI's

Roger

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

Of course.



Actually if you think about it, it happens all the time.

For example an electrical enclosure might be listed for use in 'wet locations' but that does not mean it can go in any wet location without regard for other code sections that may apply.

Lets say the wet location is also a Class 1 Div 1 location. I can't say the enclosure is OK to use there simply because it is a wet location and the fixture is wet location listed.

Lets say the wet location is beside a pool for a lighting transformer.

Can I use any wet listed enclosure or must I also comply with 680.24?

I could probably go on quite awhile finding things that you see as conflicts and I see as knowing the code before you pick equipment.



Would it be?

The fact is 110.3(B) only applies to instructions included in the 'listing or labeling' we have no way of knowing right know if the the 'No GFCI' instruction is in fact part of the listing or labeling or is just one of many suggestions.



I guess it's in the eye of the beholder.

It seems you are hell bent on finding conflicts in the NEC either real or perceived and I don't understand why.

I really doubt that this instruction is an actual part of the listing and labeling. In my opinion it is only a manufacturer's recommendation and not an listing and labeling instruction. Only instructions that are a actual part of the listing and labeling are covered by 110.3(B).
Don

< ADD MY 2¢ MODE = ENABLED >



Nahhh, that sounds like another of those "Urban Electrical Myths".

If the load device is leaking a high level of Current to another Conducting path, rather than retaining the "Majority Load Current" between the 2 (or 3) Circuit Conductors, then there is a Fault Issue incorporated within the Equipment.

If a Class A (6 ma trip threshold) GFCI Receptacle device is tripping with a Cord-Connected Appliance connected to it, there's obviously a leakage hazard.

A GFCI device _SHOULD NOT_ trip from the starting of Split Phase Induction Motors - because of one little thing: Kirchoff's Law.

The Leading (or Lagging) Current which is "established" by the Auxiliary Winding's Resistance-to-Reactance Ratio, is derived from the same source as the Main "Run" Winding's load Current.
The two currents will flow through the GFCI device, with each one being equal across the two wires of the monitored circuit.

Are all Refrigerator Compressor Motors Capacitor Start?
I figured the larger sized ones would be Cap Start (and possibly Cap Start/Run), whereas smaller and less expensive ones would be simple Split Phase Resistance Start Motors.

If there is a GFCI trip at start, chances are the Aux. Winding is leaking to the Motor's Frame, or the Start Switch is throwing a fat, sustained arc to the Motor's Frame, as it begins to open.

Seems to me if the GFCI was at the Breaker, set at 3 ma trip level, with the Branch Circuit being REALLY LONG, (and possibly run in a damp location for most of its length), AND the Refrigerator's Compressor Motor is mounted right where the condensation collects (so condensed water enters the Motor or enters frayed sections of the Cord), then we might have a "Weener" (Winner).

Not that all GFCI's developed now are 100% "Nuiscance Trip Free", but they have evolved drastically in the past 30+ years.

I agree with the consepts introduced by Article 210.8 (B)(2), to include GFCI Protection in Commercial Environments - mostly due to the Floor Cleaning scenario mentioned by others, but also from some Troubleshooting scenarios I have resolved in the past, where Personnel complain of being shocked by Refrigeration Appliances.

Most were due to either the Door Switch failure, or an internal light fixture failing, setting up a Ground Fault hazard - and the Cord was either missing its ground pin, or someone "fixed" the tripping breaker problem, by placing one of those "Ground Cheater Adapters" on the Plug.

There were a few caused by leaking elements on the Appliance, and a couple from certain installation Persons following the old:
"Grounding Conductor?..., we don't need no stinking Grounding Conductor",
and similar types of Philosopy.

In all these cases, the EGC was not effectively able to carry Ground Fault Currents.




That's really scarry to know a Manufacturer's Represenative would spew out such trash!!!

GFPE is not GFCI, and vise-versa.
GFPE is like at a 30 ma level, and is not a "Protection for Personnel" device.

< / END SUB "ADD MY 2¢" >

GFI on all recept in a comm kitchen sounded like anightmare in the making back when. We did a lot of Country Club work, and a few restuarants. Yes, ALL 120 volt receptacles, be they single, or duplex, shall be GFI.

OK, we did it! And yes, a few 'issues' arose. A 'bad' slicer! A ice crusher toy with a real problem, and a plate warmer with an attitude. A few items either to the appliance tech (or dumpster) and issues resolved.

Single recept w/deadfront, single with GF breaker, duplex GFI (all 20 amp). Bubble covers in the really wet areas, and job done.

If a GFCI trips, 99.9 percent there is a pending electrical problem with the equipment. The problem is usually when it is plug it in a regular recept, nothing happens so it wrongly assumed that the GFCI is defective. Given the ground fault is minute. It makes it hard to TS it.

I had a project where the Owner told me of a GFCI receptacle in the kitchen that was defective.

Their logic? It tripped whenever the appliance plugged into it was turned on. The receptacle didn't trip when anything else was plugged in, just this 1 appliance.
I told him to plug the thing into another GFCI and (surprise) it tripped that one.
He said that the first GFCI MUST be defective because it trips, but the others weren't going to be a problem because the appliance was only supposed to be plugged into the 'defective' receptacle.
I pointed out that the appliance must be defective and he told me "it can't be defective, it's brand new".

AUUGGHH!!!!

I hate clueless people.

I've had similar situations, ghost, where on a nuisance trip call, I'll ask (if it isnt terribly inconvenient) to plug the appliance into a different gfci circuit for comparative reference. if the other gfci trips within a similar time frame, the owner now has a demonstration that its the appliance; though the brand new issue may thicken their heads still.
even so, a different gfci "holding" the redirected appliance indicates almost nothing, possibly a gfci that has had the trip thresh-hold rise, or the other gfci is no good. (the p&s guy had also said that their gfcis don't degrade in amp sensitivity, but on failing - the ruined kind - won't reset.)

incedentally the P&S guy DID say that changing to class B protection would defeat the personnel protection purpose.

I just re-read your post - duh, you DID do the try it on another gfci. it's the "it cant be a counterfeit UL logo, it's brand new, your wiring caused it to melt" thing