[RE-wrenches] transformerless inverters and conductor colors

Fri Oct 4 11:38:05 PDT 2013

All -

Just a quick follow up to this thread. My understanding is that you can use
black USE-2 or PV Wire under the 2008 and 2011 NEC for all grounded and
ungrounded conductors.

2008 NEC has section 200.6(A)(2) Grounded Conductors which reads (it is
section 200.6(A)(6) in 2001 NEC):

"A single-conductor, sunlight-resistant, outdoor-rated cable used as a
grounded conductor in photovoltaic power systems as permitted by 690.31
shall be identified at the time of installation by distinctive white
marking at all terminations"

I wonder if the 2014 NEC has any new rules or clarifications on this. Brian
Mehalic listed a requirement in the 2014 NEC for coloring of ungrounded
wire of 6 AWG or smaller - does it have an exception for USE-2 or PV Wire
or will we need to buy special wire with red marking?

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:* Monday, September 23, 2013 9:29 PM
*To:* 'RE-wrenches'
*Subject:* Re: [RE-wrenches] transformerless inverters and conductor colors

It’s my understanding that once one goes into a covered raceway that the
double-insulated wire is no longer required.

marco

*From:* re-wrenches-bounces at lists.re-wrenches.org [
mailto:re-wrenches-bounces at lists.re-wrenches.org<re-wrenches-bounces at lists.re-wrenches.org>]
*On Behalf Of *Jesse Dahl
*Sent:* Monday, September 23, 2013 6:12 PM
*To:* RE-wrenches
*Subject:* Re: [RE-wrenches] transformerless inverters and conductor colors

Marco,

You said that after your "j-box" you will transition to THHN/THWN. Wouldn't
you still need to use PVWire or some type of jacketed cable all the way to
the inverter?

Jesse

Sent from my iPhone

On Sep 23, 2013, at 4:09 PM, Brian Mehalic <brian at solarenergy.org> wrote:

The 2014 NEC addresses this in a change in 215.12(C)(2), "Feeders Supplies
from Direct-Current Systems".  (There is similar language in 210.5(C)(2) in
regards to branch circuits).  I know many folks won't be on the 2014 cycle
for some time, but at least it is defined now.

Conductors 6 AWG or smaller have to be identified by polarity at all
termination, connection, and splice points as in one of 3 ways:

Ungrounded, positive polarity

1: red

2: red stripe along entire length (conductor cannot be white, gray, black
or green)

3: "+", "POS", or "POSITIVE" marked at least every 24 inches (again
conductor cannot be white, gray, black or green)

Ungrounded, negative polarity

1: black

2: black stripe along entire length (conductor cannot be white, gray, red
or green)

3: "-", "NEG", or "NEGATIVE" marked at least every 24 inches (again
conductor cannot be white, gray, red or green)

Additionally, the methods used must be documented and "readily available
or...permanently posted" at the equipment.

Cheers,

Brian Mehalic
NABCEP Certified Solar PV Installation Professional™ R031508-59

IREC ISPQ Certified Affiliated Instructor/PV US-0132

PV Curriculum Developer and Instructor

Solar Energy International
http://www.solarenergy.org

On Mon, Sep 23, 2013 at 3:59 PM, Ray Walters <ray at solarray.com> wrote:

Hi Marco;

Article 200.7 specifically prohibits using white wire for anything but
grounded conductors.  This came up last year on a large project with an
ungrounded array, that also had white incorrectly specified in the plans.
The appropriate colors would be red for positive, and black for negative.

R.Ray Walters

CTO, Solarray, Inc

Nabcep Certified PV Installer,

Licensed Master Electrician

Solar Design Engineer

303 505-8760

On 9/23/2013 1:27 PM, Marco Mangelsdorf wrote:

Hi all,

We’re doing more and more installs with TL inverters (SMA and P1).

I’m using double-insulated wire from the array string to the first
enclosure, as in j-box, and then transitioning to standard THHN/THWN wire.

I recently purchased some of that #10 double-insulated wire, getting a
spool of black and white.

Then after receiving the two spools it occurred to me: since the array is
ungrounded, as far as there being no grounded conductor in the circuit, did
I blow it by getting a spool of white wire?

What sayeth you all?  Can I not use that white wire in those array circuits
for TL inverters?

Thanks,

marco

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