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#164250 - 05/29/07 06:21 AM Refrigeration equipment - ground fault protection  
Texas_Ranger  Offline
Member
Joined: Dec 2001
Posts: 2,405
Vienna, Austria
Not wanting to do any more thread jacking on the air conditioner thread...
Quote
The point is as far as the NEC is concerned it does not mater what your plugging into the circuit it only matters where there receptacle is located.

It's the very same in several European countries. For example in Austria every receptacle 32A and smaller HAS to be protected by an RCD with no more than 30mA trip current. And I never heard of any problems with that, not even running 1960s vintage refrigerators. Right now we're running 2 refrigerators and an upright freezer on one RCD and had ONE inexplicable trip in over 10 years!


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#164259 - 05/29/07 12:01 PM Re: Refrigeration equipment - ground fault protection [Re: Texas_Ranger]  
renosteinke  Offline
Cat Servant
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Joined: Jan 2005
Posts: 5,316
Blue Collar Country
It may be a matter of the setting -our GFI is set at 5mA, while the AFCI is set at 30mA- or a difference in the specific electronics of the RCD.

It's a good subject for discussion, though. At least one manufacturer of high-end built-in refrigerators for the residential market (Dacor) specifically states in its' instructions that the refrigerator needs to be on its' own NON-GFI protected circuit.

Where the problem might arise is when the refrigerator is plugged into one of the counter-top 'small appliance' circuits, which are GFI protected.

A few years back, our GFI's were re-designed; the changes are claimed to reduce nuisance tripping.

Personally, I have only encountered the problem with refrigerators that were at the end of their lives - in other words, the GFI's were working as they were supposed to!

Some of the opposition seems to be based upon a 'cost/benefit analysis." That is, the cost of losing a fridge full of food, as contrasted to the small chance of a fault.


#164280 - 05/30/07 03:48 AM Re: Refrigeration equipment - ground fault protection [Re: renosteinke]  
Texas_Ranger  Offline
Member
Joined: Dec 2001
Posts: 2,405
Vienna, Austria
My post was mainly a reply to Trumpy's post who referred to NZ 30mA RCDs which are the same as ours in Europe.


#164349 - 06/01/07 01:44 AM Re: Refrigeration equipment - ground fault protect [Re: Texas_Ranger]  
Trumpy  Offline


Member
Joined: Jul 2002
Posts: 8,223
SI,New Zealand
Ragnar,
With respect to 30mA RCD's.
The fact of the matter is, that refrigeration equipment manufacturers, cannot reduce the leakage current from the compressor motor enough to satisfy anyone here that a fridge or other such appliance on an RCD supplied circuit.
Why this is Ragnar, is because the actual motor and the compressor unit are in a hermetically sealed unit, as in together.
Now, here is the sticking point, a Fuse or MCB will (or should) carry the in-rush current to start the system.
Now, in a sealed system, that should run forever.
But wait, what say that the system ices up because (in an A/C system) the person using it runs it too hard?.
(Expecting 30C out of a split system on a -10C morning is a bit much).
The more you work a refrigeration system the higher the leakage currents.
Usually the currents are in the Nano-amps, but once you leave a fridge or a freezer during the middle of summer, then it will trip an RCD .
Nothing annoys me more than hearing from a Home-owner, that the company that installed the fridge moved the wire over in the switchboard, "It took all our protection away!".
Idiots.


#164367 - 06/01/07 11:33 AM Re: Refrigeration equipment - ground fault protect [Re: Trumpy]  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,142
Estero,Fl,usa
I think these are really ground faults from the internal windings in that compressor shorting out.


Greg Fretwell

#164390 - 06/02/07 03:59 AM Re: Refrigeration equipment - ground fault protect [Re: Trumpy]  
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
Originally Posted by Trumpy
The fact of the matter is, that refrigeration equipment manufacturers, cannot reduce the leakage current from the compressor motor enough to satisfy anyone here that a fridge or other such appliance on an RCD supplied circuit.


Mike I don't understand what your saying.

Are you suggesting manufacturers can not reduce the leakage current?

Here in the US countless refrigerators and freezers are on 5 ma GFCI protection and are working fine.

The NEC requires this 5ma protection in a fast growing list of locations.




Last edited by iwire; 06/02/07 03:15 PM.

Bob Badger
Construction & Maintenance Electrician
Massachusetts

#164405 - 06/02/07 03:23 PM Re: Refrigeration equipment - ground fault protect [Re: iwire]  
mxslick  Offline
Member
Joined: Oct 2004
Posts: 803
Atomic City, ID USA
I worked with a company that sells vending machines, both refrigerated and non-refrigerated. The older machines had so much leakage current that GFI's wouldn't hold. Even when the chilling unit was replaced they'd still trip. (The chillers are usually a separate "skid-mounted" unit so it could be readily changed out in the field.) Most replacement units had new, modern compressors.

The problem seemed to lie more in the internal wiring of the machine breaking down than any problems with the chillers. Soda machines especially would have serious issues, that soda will eat up anything! smile

Some machines also had bad control transformers that would have a lot of leakage current.

Bob noted:

Quote
The NEC requires 5ma this protection in a fast growing list of locations.


IIRC, aren't ALL vending machine installations one of those locations?


#164407 - 06/02/07 04:01 PM Re: Refrigeration equipment - ground fault protect [Re: mxslick]  
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
Originally Posted by mxslick
IIRC, aren't ALL vending machine installations one of those locations?


Yes that is true, new machines are supposed to have GFCI protection built into the cord but units without this are required to be supplied by a GFCI circuit.

How this is supposed to be enforced I have no idea.

I don't have my 2005 NEC handy or I would post the section that spells this out.


Bob Badger
Construction & Maintenance Electrician
Massachusetts

#164431 - 06/03/07 10:49 AM Re: Refrigeration equipment - ground fault protect [Re: iwire]  
JohnJ0906  Offline
Member
Joined: Oct 2006
Posts: 65
Baltimore MD USA
Originally Posted by iwire
Originally Posted by mxslick
IIRC, aren't ALL vending machine installations one of those locations?


Yes that is true, new machines are supposed to have GFCI protection built into the cord but units without this are required to be supplied by a GFCI circuit.

How this is supposed to be enforced I have no idea.

I don't have my 2005 NEC handy or I would post the section that spells this out.


422.51 Cord and Plug connected Vending Machines


#164437 - 06/03/07 02:40 PM Re: Refrigeration equipment - ground fault protect [Re: JohnJ0906]  
mxslick  Offline
Member
Joined: Oct 2004
Posts: 803
Atomic City, ID USA
Bob, John, thanks for the references!! smile

At least in this case my little brain isn't off track.



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