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 <aug...@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-boun...@lists.re-wrenches.org > [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Richard L > Ratico > Sent: Monday, July 01, 2013 6:46 PM > To: re-wrenches@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" <dk...@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" <r...@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, a...@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:al...@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 --- > >>>> _______________________________________________ > >>>> List sponsored by Home Power magazine > >>>> > >>>> List Address: RE-wrenches@lists.re-wrenches.org > >>>> > >>>> Change email address & settings: > >>>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.or > >>>> g > >>>> > >>>> List-Archive: > >> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > >>>> List rules & etiquette: > >>>> www.re-wrenches.org/etiquette.htm > >>>> > >>>> Check out participant bios: > >>>> www.members.re-wrenches.org > > --- end of quote --- > > > --- end of quote --- > _______________________________________________ > List sponsored by Home Power magazine > > List Address: RE-wrenches@lists.re-wrenches.org > > Change email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out participant bios: > www.members.re-wrenches.org > _______________________________________________ > List sponsored by Home Power magazine > > List Address: RE-wrenches@lists.re-wrenches.org > > Change email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out participant bios: > www.members.re-wrenches.org > >
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