[RE-wrenches] PV Wiring methods

Kirpal Khalsa solarworks at gmail.com
Thu Nov 14 08:41:40 PST 2013


Bill.....we have been using the Hellerman Tyton Sunbundler cable
ties....They are braided stainless steel wire with a UV resistant vinyl
jacket....We have been getting them in quantities of 500 for approximately
$.59 each....for the 12" length ties....We like them alot....they do not
have any sharp edges and are easy to install....
Hope that helps....


Sunny Regards,
Kirpal Khalsa
NABCEP Certified PV Installation Professional
Renewable Energy Systems
www.oregonsolarworks.com
541-218-0201 m
541-592-3958 o


On Thu, Nov 14, 2013 at 7:46 AM, frenergy <frenergy at psln.com> wrote:

>  William, Bill....from another Bill,
>
>         Two things:  For the rest of us (maybe it's just me?!) that's
> still trying to figure out how (or why) to stuff a MC4 connector into
> conduit and my hesitation in using SS wire ties for fear of the sharp edges
> cutting or chaffing into cables, I'm open for advice. Any wire I use on the
> roof is rated for that type of service and I have some off-grid systems
> that have been in the sun for some 25 years where the wire still looks
> nearly new even when flexing it to look for checking/cracks.  It seems
> the wire/insulation can take it, thus it seems like the key to "wire
> management is to keep the wire from moving and off the roof, secured to the
> racking, thus not compromising the insulation.
>
>         I know many on this list are way past this point in their
> installation skills.  However my living in a county in the bush of just 20K
> folks, I haven't had the opportunity to install 100's of systems....yet.
> Again, I express my humble appreciation of experienced wrenches to help
> those of us working to install the tightest systems possible despite living
> in the boonies.
>
>         Details on where to source appropriate SS wire ties (rounded
> edges?, plastic coated?) would be appreciated.  My goto place for such
> things (Grainger) has "regular" SS wire ties that range from $1.50 to $3
> each, but none that I can see that address the sharp edge issue...or is
> that an issue?  Have people been using regular SS wire ties in the field
> for 10-20 years, behind a roof mounted array without any issues related to
> the wire ties?
> Thanks for your help and patience,
>
> Bill
>
> Feather River Solar Electric
> 4291 Nelson St.
> Taylorsville, CA  95983
> 530.284.7849 / 6544 fax
> "solar powered since 1982"
>
> ----- Original Message -----
> From: "Bill Loesch" <solar1online at charter.net>
> To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
> Sent: Thursday, November 14, 2013 1:34 AM
> Subject: Re: [RE-wrenches] PV Wiring methods
>
> >
> > Hi William (and any other person who wishes to describe themselves as
> > professional (designer, installer, etc.)),
> >
> > Please accept this note as confirmation that your evangelism on wire
> > management has not fallen on entirely deaf ears.
> >
> > Additionally, I'm curious how the practice of requiring a ten year
> > equipment warranty squares with the acceptance of plastic wire ties.
> >
> > Sincere thanks from one convert,
> >
> > Bill Loesch
> > Solar 1 - Saint Louis Solar
> >
> >
> >
> > On Wed, Nov 13, 2013 at 3:41 PM, William Miller wrote:
> >
> >> Bill:
> >>
> >>
> >> I respectfully disagree with your logic:  Define "perfectly
> >> installed."  If
> >> your connections are tight and permanent and the conductors are
> >> protected
> >> from damage, you have a great chance of a reliable, safe lifetime of
> >> service.  How can you guarantee that your leads will stay protected
> >> after
> >> the ties fail?  Studies show that even UV resistant wire ties will
> >> fail well
> >> before the life expectancy of the system has expired.  When the ties
> >> fail,
> >> your PV leads are hanging on the roof.  Even before the ties fail,
> >> rodents
> >> can chew on them.  Conduit was invented for a reason and we should be
> >> using
> >> it.
> >>
> >>
> >> I agree that arc-fault breakers will improve the situation, but I
> >> don't
> >> think any form of OCPD is a substitute for good wiring practices.  I
> >> think
> >> wire protection is just as important on PV circuits as it is on any
> >> other
> >> high voltage circuit.  Try getting away with wiring a rooftop air
> >> conditioning unit by tying the conductors to some metal framework with
> >> plastic ties and see how long it takes to get red-tagged by your local
> >> inspector.
> >>
> >>
> >> I suspect we've gotten to where we are on lax wire protection
> >> standards for
> >> two reasons:
> >>
> >> 1.    In the early days, PV was low voltage, 12 to 24 volts, and was
> >> treated
> >> as such, even though current capabilities exceeded that of
> >> conventional low
> >> voltage thermostat, door-bell and telephone wiring.
> >>
> >> 2.    It is my understanding that PV wiring standards in Europe are
> >> not
> >> stringent, and European demand drove the PV market for many years.
> >> Products
> >> were built to satisfy the European market and US standards had to work
> >> with
> >> the equipment available.
> >>
> >>
> >> Some would say: "if it is under the array, it is protected."  We have
> >> seen
> >> PV wire getting damaged under arrays and it is possible to get damaged
> >> under
> >> BPIV components as well.  I believe that protecting PV wire is more
> >> important than protecting conventional AC circuit wiring because PV
> >> circuits
> >> are more prone to create and sustain arcing.
> >>
> >>
> >> Some say that protecting PV wire in conduits will add too much expense
> >> to PV
> >> installations.  Consider the cost of fires and, inevitably, injuries
> >> and
> >> deaths.  One news story about an obscure, rarely used product is
> >> already
> >> causing many of us headaches.  Statistically, it is inevitable that
> >> more
> >> accidents will happen. I don't want that on my conscience.
> >>
> >>
> >> I would suggest that we need to expand the discussion beyond fire
> >> hazards.
> >> I also worry about electrocution hazards in high voltage PV circuits.
> >> Good
> >> wire protection is essential in preventing contact with high voltages.
> >>
> >>
> >> Unprotected PV wiring is an irresponsible practice.  I am fighting an
> >> uphill
> >> battle to develops methods to protect PV wiring because the industry
> >> is not
> >> helping at all.  The trend has been to make it harder to protect
> >> wiring.
> >> This trend will result in accidents.  I think we should do better.
> >>
> >>
> >> Sincerely,
> >>
> >>
> >> William Miller
> >>
> >>
> >>
> >> From: re-wrenches-bounces at lists.re-wrenches.org
> >> [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Bill
> >> Brooks
> >> Sent: Monday, November 11, 2013 3:38 PM
> >> To: 'RE-wrenches'
> >> Subject: Re: [RE-wrenches] RE-wrenches Digest, Vol 6, Issue 423
> >>
> >>
> >> William and David,
> >>
> >>
> >> This particular problem goes away with arc fault detection. The longer
> >> we
> >> wait to introduce arc fault detection into our systems, the more we
> >> will
> >> have opportunities for news reports such as the one William brings
> >> forward.
> >> Wire ties are not the problem. Could a wire tie cause a problem-sure,
> >> just
> >> like anything improperly installed.
> >>
> >>
> >> At the end of the day, you can a have a perfectly installed system,
> >> but if
> >> it does not have arc fault detection and high resolution ground fault
> >> detection, it can still catch on fire. You have no control over
> >> product
> >> failures other than buying from large companies that can actually
> >> insure
> >> their products in a failure.
> >>
> >>
> >> Fires are not that common, but it didn't take much to get all the
> >> viewers of
> >> this news report up in arms did it?
> >>
> >>
> >> Bill.
> >>
> >>
> >>
> >>
> >>      ------------------------------
> >>
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