[RE-wrenches] transformerless inverters and conductor colors

Brian Mehalic brian at solarenergy.org
Mon Sep 23 14:09:13 PDT 2013


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 Engineer303 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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