[RE-wrenches] transformerless inverters and conductor colors

[August Goers]

Marco,



My understanding is that PV wire is a separate listing. Exposed DC wiring
with ungrounded non-isolated systems must be PV wire. USE-2 wire is not
necessarily PV wire unless listed and labeled as PV wire. Here's a decent
article:



http://www.renewableenergyworld.com/rea/news/article/2010/11/performancecost-trade-offs-in-pv-systems-wiringcabling-selection



Best, August



*From:* re-wrenches-bounces at lists.re-wrenches.org [mailto:
re-wrenches-bounces at lists.re-wrenches.org] *On Behalf Of *Marco Mangelsdorf
*Sent:* Friday, September 27, 2013 12:24 AM
*To:* 'RE-wrenches'
*Subject:* [RE-wrenches] transformerless inverters and conductor colors



Thanks, Glen.



This brings up the question of what exactly constitutes “PV Wire.”   “PV
wire” does not necessarily = double-insulated wire which I thought is
required with ungrounded PV systems on the DC side at least until you hit
an enclosure and enclosed raceway where you can transition to THWN-2 wire.
Is there a clear and unambiguous definition out there of what constitutes
“PV Wire”?  To some XLP/USE-2/RHW-2 wire is “PV Wire.”



marco



2008 NEC



690.35 Ungrounded Photovoltaic Power Systems.

Photovoltaic power systems shall be permitted to operate with ungrounded
photovoltaic source and output circuits where the system complies with
690.35(A) through (G).

(A) Disconnects.

(B) Overcurrent Protection.

(C) Ground-Fault Protection.

(D)  The photovoltaic source conductors shall consist of the following:

(1)          Nonmetallic jacketed multiconductor cables

(2)          Conductors installed in raceways, or

(3)          Conductors listed and identified as Photovoltaic (PV) Wire
installed as exposed, single conductors.



Raceway.  An enclosed channel of metal or nonmetallic materials designed
expressly for holding wires, cables, or busbars, with additional functions
as permitted in this Code. Raceways include, but are not limited to, rigid
metal conduit, rigid nonmetallic conduit, intermediate metal conduit,
liquidtight flexible conduit, flexible metallic tubing, flexible metal
conduit, electrical nonmetallic tubing, electrical metallic tubing,
underfloor raceways, cellular concrete floor raceways, cellular metal floor
raceways, surface raceways, wireways, and busways.



Reads to me like you can transition to THWN-2 inside a rooftop jbox from
the PV wire under the modules, as long as it is in a raceway.



-Glenn Burt
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