Respectfully: 
My Fluke 87 does not use this convention. Black is labeled the COMMON terminal,
the red terminal is labeled according to function, not polarity. Battery based
inverter manus. using this convention typically provide BOS enclosures with OCP
for only one inverter conductor. This requires the other conductor to be
grounded and colored white or gray. Therefore IMHO the manus. should use only +
or - to identify inverter terminals. Many, if not most, battery companies do
this already. Mr. Wiles is, of course, welcome to his opinion. 

I would suggest we stay with the NEC required use of any color other than white,
green or gray for ungrounded conductors. This gives installers some flexibility.
It also encourages the guy on the hot roof or the gal in the stuffy mechanical
room to check and double check, maybe triple check polarity, as they should be
doing anyway. I do like the practice of enhanced identification of conductors in
positive ground systems.

Dick Ratico
Solarwind Electric


--- You wrote:
The convention of red for positive and black for negative is not just 
automotive.  It is also used by all battery based inverter manus, all 
battery companies, and all multimeters.
John Wiles also agrees;
red = positive, black = negative  for ungrounded systems
red = positive, white = negative for negative grounded systems
white = positive, black = negative for pos grounded systems.
I take it a step further, and use white label tape with red lettering 
that says "+ positive ground + ",
because I've seen so many problems with positive grounded systems, and 
people not getting polarity correct.
All of this is NEC compliant, and follows standard conventions.
Make it easy on yourself and your journeymen on a hot roof, and have 
your color coding match their multimeter.
You might save an inverter or even a life.

R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760

On 6/28/2013 12:09 PM, Allan Sindelar wrote:
> On 6/28/2013 11:47 AM, aram@aramsolar.com wrote:
>> And of course Red for positive and black for negative.
>> Most building departments have not pick up on this yet. But they will.
>> Aram
>
> Where does "of course Red for positive and black for negative" come 
> from, please? I only know it as an automotive standard that has often 
> caused confusion when used by DIY offgridders in years past, as black 
> thus could represent either positive or negative in a DC conductor pair.
> Is there yet a convention for ungrounded arrays? While red and black 
> are technically correct as ungrounded current-carrying conductors, use 
> of this color convention could cause as much confusion as resolve it 
> in the future. How about "black and black" or for that matter "yellow 
> and orange" (if supplied by manufacturers) for ungrounded arrays?
> Thanks, Allan
>
> *Allan Sindelar*
> _Allan@positiveenergysolar.com_ <mailto:Allan@positiveenergysolar.com>
> NABCEP Certified PV Installation Professional
> NABCEP Certified Technical Sales Professional
> New Mexico EE98J Journeyman Electrician
> Founder and Chief Technology Officer
> *Positive Energy, Inc.*, a Certified B Corporation^TM
> 3209 Richards Lane
> Santa Fe, New Mexico 87507
> *505 424-1112 office 780-2738 cell*
> _www.positiveenergysolar.com_ <http://www.positiveenergysolar.com/>
>
--- end of quote ---

