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#164202 05/27/07 06:08 PM
Joined: Sep 2006
Posts: 26
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A couple of days ago, I bought one of those cheap Chinese built Haier window airconditioners at Target for a doghouse/storage shed project. It was a 5200 BTUH unit, 120 volts. I was kind of surprised to see that it came with a GFI built into the plug, but what made me wonder was the warning label attached to the cord which read like this:

CAUTION:

The conductors inside this cord are surrounded by shields, which monitor
leakage current. THESE SHIELDS ARE NOT GROUNDED.

Periodically examine the cord the any
damage. DO NOT USE this product in the
even the shield becomes expose.

Anybody have any idea what their "monitoring shields" are, and are they required by code or what????


Last edited by Beachboy; 05/27/07 06:13 PM.
Joined: Jan 2005
Posts: 5,316
Cat Servant
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Technically speaking, the device on the cord is dot a GFI .... like the things on hair dryer cords, they perform a similar function, but are tested to a different standard.

I do not know the details of their operation, or why the special cord is used. All I know is that it was yet another of those 'stealth' changes that all products opf the type must meet.

NEC 440.65 is where the requirement is found.

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This is the link to the Tech notes PDF http://www.fireshield.com/04_0301TechNotes.pdf

Joined: Jul 2002
Posts: 8,412
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Beachboy,
Just as a note, I was roundly dressed down during my time as an Electrical Apprentice for installing an Air Conditioning unit on an RCD (same as a GFCI), even though the thing was a temporary supply with a socket-outlet on the outside of the house, I was told that it shouldn't have been fed via an RCD.
Word came back that the RCD kept tripping because of the compressor leakage currents.
Some electrician's have been caught red-faced with wiring houses here where the fridge or a freezer have been plugged into an RCD-protected outlet, but with the thing tripping months later (home-owners never test them either which doesn't help), usually when the home-owner is away getting some sun overseas during the Winter here.
My advice would be, stay well away from GFCI circuits and Refrigeration/Aircon circuits, as far as mixing the two go.
It will only end in tears.
Refrigeration and A/C manufacturers were supposed to have all of their leakage currents down under the level that would trip an RCD/GFCI, Yay, great to see they took that seriously!.
Once again it is the Electrician that bears the blame.

Joined: Jan 2003
Posts: 4,391
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Originally Posted by Trumpy
My advice would be, stay well away from GFCI circuits and Refrigeration/Aircon circuits, as far as mixing the two go.
It will only end in tears.


Mike that is not a choice under the NEC, currently the NEC requires GFCI protection on all 125 volt 15 & 20 amp commercial kitchen receptacles to have GFCI protected, many of these circuits will feed refrigeration equipment.

In dwelling unit Garages and basements GFCI protection is required and currently there is an exception for appliances in a dedicated space. When the 2008 NEC comes out the exceptions will be gone, if you place a spare freezer in the basement it will be GFCI protected.

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.

The one exception is for ice melting equipment as it has a high leakage current by design.

One last thing, according to the NEC hand book they do not believe it is the compressor causing the false trips, they believe it has to do with the electric defrost circuits in many refrigeration appliances.

Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts
Joined: Nov 2000
Posts: 2,148
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440.65 Leakage Current Detection and Interruption (LCDI) and Arc Fault Circuit Interrupter (AFCI)
Single-phase cord-and-plug-connected room air conditioners shall be provided with factory-installed LCDI or AFCI protection. The LCDI or AFCI protection shall be an integral part of the attachment plug or be located in the power supply cord within 300 mm (12 in.) of the attachment plug.


Don(resqcapt19)
Joined: Jan 2005
Posts: 5,316
Cat Servant
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Let's not muddy the waters with too many variations. The OP was asking about the device that came with the air conditioner.... not the house wiring, or HVAC stuff in general.

I note that the NEC equates these particular devices to AFCI devices ... which suggest that they will tolerate a higher leakage current than a GFCI, perhaps as high as 30mA.

That, in turn, does suggest that there might be a problem if an air conditioner is added to a GFCI protected circuit.

Somehow these problems magically disappear if the unit is 'hard wired.'

Joined: Jan 2003
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Originally Posted by renosteinke
The OP was asking about the device that came with the air conditioner


That is true and that question was answered, Mike brought up GFCIs in general, I was responding to that.

Originally Posted by renosteinke
Somehow these problems magically disappear if the unit is 'hard wired.'


Yes, just like a circuit that is overloaded is 'magically fixed' by switching to a larger breaker. smirk

If the unit has 30 MA of leakage current and it loses the ground it is now deadly.



Bob Badger
Construction & Maintenance Electrician
Massachusetts
Joined: Nov 2000
Posts: 2,148
R
Member
Quote

Somehow these problems magically disappear if the unit is 'hard wired.

The GFCI or leakage protection rules are mostly directed at cord and plug connected equipment because that equipment is more likely to lose its EGC connection than is hardwired equipment.
Don


Don(resqcapt19)
Joined: Jan 2005
Posts: 5,316
Cat Servant
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Thank you, Don and Bob. I was not aware that was the reasoning behind this, and similar requirements in the NEC.

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