[RE-wrenches] double insulated/PV wire

Tue Jul 2 09:56:01 PDT 2013

Sorry for my density..is "PV wire" necessarily double insulated?

Thanks,

marco

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Jason
Szumlanski
Sent: Tuesday, July 02, 2013 6:52 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] double insulated wire

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 <tel:303%20505-8760> 

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 <tel:%28264%29%20235-5670> 
> St. Kitts  (869) 662-5670 <tel:%28869%29%20662-5670> 
> 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 <tel:303%20505-8760> 
>>>
>>> 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 <tel:303%20505-8760> 
>>>>
>>>> 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 <tel:505%20424-1112>  office 780-2738 cell*
_www.positiveenergysolar.com_
>>>>> <http://www.positiveenergysolar.com/>
>>>> --- end of quote ---
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