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#167017 - 08/04/07 03:13 AM article 210.8(B)(2)  
Samurai  Offline
Member
Joined: May 2007
Posts: 46
Fl.
(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.


2017 / 2014 NEC & Related Books and Study Guides

#167021 - 08/04/07 06:36 AM Re: article 210.8(B)(2) [Re: Samurai]  
Roger  Offline
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Joined: May 2002
Posts: 1,716
N.C.
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

Quote
Ground-Fault Circuit Interrupter (GFCI). A device intended for the protection of personnel that functions to de-energize a circuit or portion thereof within an established period of time when a current to ground exceeds the values established for a Class A device


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

Last edited by Roger; 08/04/07 06:39 AM.

#167023 - 08/04/07 07:49 AM Re: article 210.8(B)(2) [Re: Roger]  
iwire  Offline
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Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
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.


Bob Badger
Construction & Maintenance Electrician
Massachusetts

#167025 - 08/04/07 11:13 AM Re: article 210.8(B)(2) [Re: iwire]  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,103
Estero,Fl,usa
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.


Greg Fretwell

#167028 - 08/04/07 11:41 AM Re: article 210.8(B)(2) [Re: gfretwell]  
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
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. smile



Bob Badger
Construction & Maintenance Electrician
Massachusetts

#167030 - 08/04/07 12:03 PM Re: article 210.8(B)(2) [Re: iwire]  
Alan Nadon  Offline
Member
Joined: Mar 2005
Posts: 399
Elkhart, IN. USA
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. smile
Alan


Alan--
If it was easy, anyone could do it.

#167031 - 08/04/07 01:18 PM Re: article 210.8(B)(2) [Re: iwire]  
Samurai  Offline
Member
Joined: May 2007
Posts: 46
Fl.
Originally Posted by iwire

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.


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

Last edited by Samurai; 08/04/07 01:28 PM.

#167036 - 08/04/07 01:39 PM Re: article 210.8(B)(2) [Re: Samurai]  
renosteinke  Offline
Cat Servant
Member
Joined: Jan 2005
Posts: 5,316
Blue Collar Country
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.


#167040 - 08/04/07 02:41 PM Re: article 210.8(B)(2) [Re: renosteinke]  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,103
Estero,Fl,usa
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?


Greg Fretwell

#167044 - 08/04/07 02:57 PM Re: article 210.8(B)(2) [Re: renosteinke]  
Roger  Offline
Member
Joined: May 2002
Posts: 1,716
N.C.
Originally Posted by renosteinke
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."


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


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