[RE-wrenches] double insulated wire

Tue Jul 2 11:15:18 PDT 2013

Hi Dick;

What you're suggesting is actually something I thought would work too: 
having totally odd colors that immediately said DC.
IT really would be the best, because if you go in with a meter set to 
read AC, and show no voltage, then get your voltage sniffer out, and it 
doesn't beep, you think you're double safe, when actually you could get 
hit with 500 v dc.

I try and mark every J-box that has DC conductors in it with the DC 
voltage.  The life I save probably will be my own, as I'm getting more 
forgetful with age......

I think one of the problems is that this is actually not a NEW issue;  
we are reviving the 100+ year old AC vs DC battle that Edison 
Westinghouse, and Tesla, et al. fought before.  Factories have AC and DC 
on site, and it just amazes me that marking polarity isn't required by 
code.  We have to mark the bonded conductor, or the high leg in certain 
3 phase systems, so identifying DC polarity seems just as important.
I actually really like your purple with a white stripe idea.  At one 
time I tried to color code for DC voltage too, (Red for 12 v, purple for 
24, Orange for 48 v) and even used yellow tape for my PV inputs as they 
had a higher V than the battery.  Now I just try to label everything 
copiously, and have polarity align with my meter.
My biggest problem is still old 12 v house wiring on Romex (white and 
black)  or which side of those Monkey face outlets should be + or - 
......  These days, I just try to switch the circuit over to AC   (go 
Tesla!)

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

On 7/1/2013 7:46 PM, Richard L Ratico wrote:
> 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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