PVGFP [RE-wrenches]

[Jeffrey Wolfe, Global Resources]

Holt,

With a PVGFP, the ONLY place that the ground and neutral can come together, 
in the whole DC system, is at the PVGFP. So if you've got the ground and 
neutral tied together at the EZ Wire, then that's your problem. You need to 
unbond those neutrals, and ground the EZ Wire cabinet separately.

Truly a pain and pretty tough to justify, (right Bob-O?) but if you want it 
to meet the code entirely, that's what you've got to do if the PV is on a 
dwelling. And don't forget to unbond the ground and neutral in the Trace 
DC250 (if that's what you're using.) This means putting another neutral bus 
into the DC250, and disconnecting the shunt from the existing ground block. 
(either connect the shunt to a new ground block isolated on a piece of 
plywood, or make a bus bar and directly attach to the shunt.)

Gets crowded in that DC 250.

Jeff

----------
From: 	Holt Kelly[SMTP:hkelly6 at msn.com]
Reply To: 	RE-wrenches at topica.com
Sent: 	Wednesday, August 01, 2001 2:19 PM
To: 	RE-wrenches at topica.com
Subject: 	[RE-wrenches]

Hello all,
Andrew McCalla and I did a "re-do" on a system recently. Whisper 3000
w/EZ Wire, 950w of PV. We added a PVGFP to the system as the array is
roof mounted. A problem occured on final check of system. The GFP kept
tripping when two 40amp PV breakers were switched on. Below is Andrew's
communication with Southwest Windpower. Anyone encountered this with the
EZ wire? (I did not include schematic attachment with this post- contact
me off-list if you would like to view it)

To Southwest Windpower:
I have done many systems with this particular GFP (ground fault
protection)mechanism and have never run into any problems.  The EZ Wire
threw us a curve because the GFP usually accepts the input directly from
the array disconnect, before continuing on to the charge controller.
Since these two are so intertwined in the EZ Wire, we accomplished this,
as you can see, by simply putting in an additional breaker between the
array and the GFP.

The GFP is does not trip unless both breakers (the two PV 40 Amp
breakers)are on.  If we bypass the GFP, the EZ Wire will receive
current.  Therefore, the GFP is sensing a ground fault.

Could this be due to the fact that there is continuity between the
bonded negative terminals on the EZ Wire and the EZ Wire cabinet itself?
 As I indicated to you over the phone, I could find no documentation
regarding the subject of grounding in the EZ Wire manual.



"We do not inherit the earth from our parents. We borrow it from our
children."
Chief Seattle

Holt E. Kelly
Holtek Fireplace & Solar Products
Waco, TX.
hkelly6 at msn.com

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