About the PVGFP [RE-wrenches]

[William Miller]

Friends:

I've put in several of the PVGFP circuit breakers from Trace.  I have some
questions about installing this unit:

There is a white lead, about 2/0, that connects to the isolated negative
buss and a green lead that looks slightly smaller, that connects to the
bonded buss.  In the manual it says that these leads can be lengthened or
shortened but can not be replaced.  It goes on to say that these leads
"have been factory installed and torqued to UL standards."  Furthermore the
manual says, "NEC does not allow field connections of two wires (over 12
AWG) in one pressure terminal."  Inspection of these units shows that there
are two leads, one of the heavy ones described above, and a smaller lead in
each lug on the 1 amp pole of the breaker.

What I get out of this is that a factory can put two wires in one lug but a
field installer cannot.  It can be awkward to have to splice onto one or
both of these leads and the temptation is to replace the lead with a longer
one.  If the torque is so critical, I do not understand why the manual
says, "Periodic tightening of all wire connections... is highly
recommended."  Also, why is there such heavy gauge wire connected to a 1
amp circuit breaker?  Am I required to add wire of the same gauge?
Comments are requested.

On the same subject, does anyone think it odd that these breakers cannot be
purchased with an enclosure?  I accidentally discovered that a Murray
LC008DS load center is a great enclosure for the PVGFP, either in the Nema
1 or Nema 3R style.  One just removes the interior and screws or rivets in
the GFP breaker.  For the 3 pole or less breakers (actual poles) one can
use the breaker KOs as they are.  For the 4 pole model, you have to knock
out on both sides of the center and cut out the center web and then supply
a small plate to block the side of the larger opening.  What are the rest
of you doing for enclosures for the PVGFPs?

Also, I called Trace to ask what to use for an isolated negative buss.
They suggested a DCBB on a piece of wood!  I did some research and found
that the Ilsco PDB-24-500-1 power distribution block fit (snugly) into a
DC250 and worked well as an isolated negative.  I can send a photo of
anyone is interested.

Which brings me to another complaint, that of how small the DC250
enclosures are...  But I'll save that for another post.

Thanks in advance for your comments.

William Miller


__________________________________________________________________
William Miller
SLO Communications: Communications and Power Systems Consulting
Chief Engineer, KCBX: NPR and PRI for San Luis Obispo and Santa Barbara
PO Box 50, Santa Margarita, CA 93453
Voice :805-438-5600		Fax: 805-438-4607	VMail: 805-546-4875
email: wrmiller at slonet.org
License No. C-10-773985
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