[RE-wrenches] transformerless inverters and conductor colors

[Marco Mangelsdorf]

Thanks.

 

Does this wire have "PV Wire" written on the insulation jacket?

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of August Goers
Sent: Friday, September 27, 2013 7:38 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] transformerless inverters and conductor colors

 

Marco,

 

Yes, there is single jacketed PV wire. I've attached a spec sheet for some
1000 V wire we've been using. I don't know anything about the actual wiring
construction and why single versus double jacketing may or may not be used.
I just know it needs to be listed for the purpose.

 

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 10:28 AM
To: 'RE-wrenches'
Subject: [RE-wrenches] transformerless inverters and conductor colors

 

Thanks, August.

 

OK, so I've found "PV wire" that's double-insulated.  (See attached spec
sheet from Falcon wire.)

 

Is there PV wire out there that's just got a single insulation layer that
qualifies as per what came from that helpful article below?

 

marco

USE-2 is a standard wire designated for underground service entrance,
typically used to connect terminals of a variety of service equipment. PV
wire is specifically designated for use in PV module interconnections. Both
cables are rated for 90oC wet or dry. PV wire, however, has thicker
insulation to withstand the harsh environments frequently found in PV
installations. USE-2 carries a 600V rating, whereas PV wire can be rated at
600V, 1000V or 2000V. There are separate ratings with increased insulation
thickness for each cable.

Both USE-2 and PV wire can be used with grounded systems, but only PV wire
may be used with ungrounded systems per NEC 2008. Since USE-2 has typically
been installed underground or in environments where flame is unlikely, it
usually does not require a flame retardant rating. The PV wire designation
does include a VW-1 flame test requirement. Both ratings are sunlight
resistant, but the PV wire rating applies a more stringent test requirement
of 720 hours in weatherometer vs. 300 hour weatherometer test for USE-2.

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of August Goers
Sent: Friday, September 27, 2013 4:18 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] transformerless inverters and conductor colors

 

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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