[RE-wrenches] double insulated wire

Tue Jul 2 09:52:10 PDT 2013

No wiring color convention or code requirement will reduce the need to
check (double-, triple-check) polarity during any DC wiring task. I'd
almost prefer everything to be black except the grounded conductor (white
if present) and grounding conductors in a DC system.

(opinions stated without consideration of code or convention)

Jason Szumlanski
Fafco Solar

On Tue, Jul 2, 2013 at 10:09 AM, August Goers <august at luminalt.com> wrote:

> The most common mistake I've seen is not correctly using white/gray for
> the grounded conductor on the DC side. I've seen errors most commonly with
> positive grounded systems (SunPower) but often times installers use black
> in place of white or something along those lines. It definitely gets
> confusing. Otherwise, my opinion is that you can basically do what you
> need with white, black, red, and green for the majority of isolated and
> non-isolated PV systems with relatively little confusion as long as
> everything is well labeled. Corey Shalanski's color coding sheet looked
> good to me. We've tried different colors such as purple and orange and
> having the extra rolls of wire in the warehouse and other new conventions
> just causes more confusion. If I'm troubleshooting a system installed by
> someone else I'm going to check everything with my multimeter before
> concluding how everything is wired. Wire color isn't going to help that
> much other than giving me a few hints on what the other installer was
> thinking.
>
> Best, August
>
> -----Original Message-----
> From: re-wrenches-bounces at lists.re-wrenches.org
> [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Richard L
> Ratico
> Sent: Monday, July 01, 2013 6:46 PM
> To: re-wrenches at lists.re-wrenches.org
> Subject: Re: [RE-wrenches] double insulated wire
>
> Ray,
> I really DO get it. But, after 20 years of mostly working with AC, almost
> always terminating black conductors to the left of red conductors: black -
> red, black - red, black - red..... I don't think it's much of a mental
> stretch to see how RED
> - BLACK might possibly cause some confusion in the heat of the moment.
> What say the negative conductor was required to be purple or purple with a
> white stripe when grounded, or some other very infrequently used or even
> completely new color, or color combination? Some system that immediately
> screams "DC!". Would that not make more sense?
>
> It's still a new world, having DC and AC conductors terminated in the same
> system and enclosure. Thanks for the conversation.
> And keep an eye on those electricians ;-)
>
> Dick Ratico
> Solarwind Electric
>
>
> --- You wrote:
> Dick;
>
> I'm not advocating for  a color coding system I invented.  It is not
> dependent on how a wrench's head is wired; its corresponds to how his
> meter is wired.  This is simply combining NEC compliance with almost
> universal common practice (batteries, automotive, forklifts, multimeters,
> battery based inverters)
>
> R.Ray Walters
> CTO, Solarray, Inc
> Nabcep Certified PV Installer,
> Licensed Master Electrician
> Solar Design Engineer
> 303 505-8760
>
> On 6/30/2013 9:58 AM, Richard L Ratico wrote:
> > Ray,
> > Conductors can be mislabled regardless of the system used. The
> > accident you described had nothing to do with conductor color or
> > labeling. It was caused by
> a
> > gross violation of sound electrical procedure and plain common sense.
> > Your electricians failed to check for correct polarity before making
> > their terminations.
> >
> > I grant your system works for you and could for others. But until the
> > NEC
> forces
> > us all onto the same page, an argument can be made that any coding
> > system is
> as
> > confusing as another. Pardon the pun, it depends on the way a
> > wrenches's head
> is
> > wired.
> >
> > Dick Ratico
> > Solarwind Electric
> >
> >
> > --- You wrote:
> > We have standardized on DC markings White negative and Red positive.
> >
> > Chris Mason
> > Comet Systems
> > Anguilla (264) 235-5670
> > St. Kitts  (869) 662-5670
> > skype netconcepts
> >
> > NABCEP Certified Solar PV InstallerTM
> > Renewable Energy Systems professional
> > Generac Generators Factory technician
> > On Jun 29, 2013 8:30 PM, "David Katz" <dkatz at aeesolar.com> wrote:
> >
> >> Watch out for accountants who become installers.  They always thing
> >> red negative and black positive.
> >> David Katz
> >>
> >> Sent from my iPhone
> >>
> >> On Jun 28, 2013, at 5:40 PM, "Ray Walters" <ray at solarray.com> wrote:
> >>
> >>> Richard, when you use your Fluke 87  to measure Vdc, black is
> >>> negative, red is positive.  The black is labeled common because the
> >>> meter can also be used for current measurements. (I have a Fluke 89)
> >>> When you start using black wire for positive, it may be allowed by
> >>> code, but there just isn't a good reason for it.
> >>> Its just too easy to make a mistake, and its just too easy to adhere
> >>> to the multimeter convention and keep it safer.
> >>>
> >>> I have personally watched seasoned electricians argue color coding
> >>> with me, then minutes later get mixed up and wire two 10 module
> >>> strings in series, because they forgot for a moment that they were
> >>> working on a positive grounded system.  The result was an almost
> >>> 1000 v arc that jumped an opened fuse holder (only rated to 600 vdc)
> >>> and started a small fire in the inverter, before I disconnected it at
> the array.
> >>>
> >>> Please give one example where leaving positive unmarked with black
> >>> wire makes more sense than taping it.  Colored electrical tape, and
> >>> label tape are much cheaper than inverters and people.  THHN, USE,
> >>> and PV wire can all be purchased in red, white, and black. (which
> >>> saves time with multiple  home runs) Its not code yet, but it's good
> >>> sense, all the way back to the color coded jumper cables you might
> >>> have in your trunk.
> >>> I have discussed this with many electricians over the years, but
> >>> eventually every single one sees that's its really easy, no cost,
> >>> and still code compliant to make things safer.
> >>>
> >>> R.Ray Walters
> >>> CTO, Solarray, Inc
> >>> Nabcep Certified PV Installer,
> >>> Licensed Master Electrician
> >>> Solar Design Engineer
> >>> 303 505-8760
> >>>
> >>> On 6/28/2013 2:49 PM, Richard L Ratico wrote:
> >>>> 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 at 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 at positiveenergysolar.com_
> >>>>> <mailto:Allan at 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 ---
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