[RE-wrenches] Stainless Steel Cable Ties

Thu Apr 25 10:19:32 PDT 2013

Ray,

Your points all seem good. And I echo the other comments that white non-UV
zip ties should never be used. I bumped into a tracker installation a few
weeks ago out in the Fresno area with very poor wire management! See
attached pic - I have no idea who installed the system or when. It looks
like the wire management was never any good in the first place although if
you zoom in you'll see traces of a few white zip ties here and there that
seem to be falling apart.

We've managed to get our rooftop installations to be completely managed
with stainless s-clips and then maybe just a couple black plastic zip ties
in critical locations. So far so good. A lot of it just goes back to good
craftsmanship and running the PV wire in strategic locations so it's mostly
supported by channel or rail. A tracking system is a completely different
story where the wires will be moving as the system tracks. Plastic zip ties
clearly don't seem like a good idea for tracking applications.

Best,

August

*From:* re-wrenches-bounces at lists.re-wrenches.org [mailto:
re-wrenches-bounces at lists.re-wrenches.org] *On Behalf Of *Ray Walters
*Sent:* Thursday, April 25, 2013 9:30 AM
*To:* Solar Energy Solutions; RE-wrenches
*Subject:* Re: [RE-wrenches] Stainless Steel Cable Ties

Black UV resistant ties only last a few years at altitude in New Mexico and
Colorado.  UV is brutal, and causes PVC conduit to discolor within 2
years.  The zips will actually hold for 10+ years, but aren't really
strong.  I've come back on my own work, and just yanked on them, and popped
them right off.
They just get very brittle. If on a tracker that is constantly pulling on
them, they'll be trash on the ground after less than 5 years.  I use wire
loom clamps with rubber insulators in those cases, and then the zip ties
just hold the bundle of wires together, but aren't actually securing the
wire to the structure.
I looked into this recently for a large PV installation company and I found
that Nylon 6.6 is probably the best, but the specified design life of the
zip when exposed to UV was 6 to 10 years.  We found a nylon zip rated to
over 15 years, but it was special order and cost something like $2/ ea
(cough, cough)
I like the idea of SS ties, but they are not the same as the SS clips as
mentioned.   The clips have curved edges that won't cut into the cables.
USE wire actually is pretty easy to cut into, and I've seen a few shorts
due to metal cutting into it. ( module edges, romex type connectors, etc)
I would wrap the wire with a thick electrical tape before zip tieing with
SS ties. There is a heavy mil pipe wrap tape (UV and underground rated)
that plumbers use on gas lines.

R.Ray Walters

CTO, Solarray, Inc

Nabcep Certified PV Installer,

Licensed Master Electrician

Solar Design Engineer

303 505-8760

On 4/25/2013 9:48 AM, Solar Energy Solutions wrote:

We have used black cable ties since 1987 to strap sensor wire to PVC pipe
for our solar pool heating systems.  I was just at a system we installed in
1989 mounted on an East facing roof yesterday.  The exposed 20g sensor wire
still had intact and plyable sheilding and the black cable ties still
firmly attached and not brittle.  We have other similiar scenes with
systems mounted on South facing roof were the black cable ties are still in
tact under full solar exposure... for Portland Oregon.  Yanking on some of
these cable ties sometimes break the ancient tie.  But, more often than
not, as yesterday, we have to break out our wire cutters to accomplish this
task.

Thus, I gotta think that black cable ties under a PV array which are not
exposed to any of the heat or sun we usually subject them to... are going
to last an even longer time.

*Andrew Koyaanisqatsi*

President

*Solar Energy Solutions, Inc.*

Since 1987,

Moving Portland and Beyond

to an Environmentally Sustainable Future.

*503-238-4502*

*http://www.solarenergyoregon.com/ *

*"Better one's House too little one day*

*than too big all the Year after."*

*From:* Chris Mason <cometenergysystems at gmail.com><cometenergysystems at gmail.com>
*To:* RE-wrenches
<re-wrenches at lists.re-wrenches.org><re-wrenches at lists.re-wrenches.org>
*Sent:* Thursday, April 25, 2013 8:12 AM
*Subject:* Re: [RE-wrenches] Stainless Steel Cable Ties

Make sure you use black cable ties, the white ones fail in UV from sunlight.

On Thu, Apr 25, 2013 at 11:06 AM, August Goers <august at luminalt.com> wrote:

I too share the concern about standard plastic zip ties. However, I started
in the industry in 1997 and have yet to see zip ties that are falling
apart. Does anyone on the list have firsthand experience with failed
plastic zip ties?

Best,

August

August Goers

Luminalt Energy Corporation

1320 Potrero Avenue

San Francisco, CA 94110

m: 415.559.1525

o: 415.641.4000

august at luminalt.com

*From:* re-wrenches-bounces at lists.re-wrenches.org [mailto:
re-wrenches-bounces at lists.re-wrenches.org] *On Behalf Of *Solarguy

*Sent:* Thursday, April 25, 2013 7:08 AM
*To:* 'RE-wrenches'
*Subject:* Re: [RE-wrenches] Stainless Steel Cable Ties

We have used 8” flat  SS ties for years and I have no concern about the
wear on the conductor insulation. They are long enough to circle a standard
Unirac rail and several wires leaving 1” or so tag end. Needle nose pliers
work to twist the end and snug down the tie as tight as you’re comfortable
with. The metal tie, once bent around the corners cannot stretch any
tighter, unlike nylon, regardless of how tightly you twist the pliers. As
for the edges, quality ties are not sharp. Or cheap.

Jim Duncan

North Texas Renewable Energy Inc

http://www.ntrei.com/

NABCEP PV 031310-57

TECL-27398

ntrei at 1scom.net

817.917.0527

*From:* re-wrenches-bounces at lists.re-wrenches.org [
mailto:re-wrenches-bounces at lists.re-wrenches.org<re-wrenches-bounces at lists.re-wrenches.org>]
*On Behalf Of *Jason Szumlanski
*Sent:* Thursday, April 25, 2013 8:08 AM
*To:* RE-wrenches
*Subject:* Re: [RE-wrenches] Stainless Steel Cable Ties

There was a recent thread about wire management. Heyco SunBundler ties have
a vinyl coating. I recommended the clips from PV Racking that are stainless
steel coated in rubber. I've had the same concern, and both of these seem
like good solutions to me.

*Jason Szumlanski** *

*Fafco Solar*

On Thu, Apr 25, 2013 at 1:20 AM, Benn Kilburn - DayStar Renewable Energy <
benn at daystarsolar.ca> wrote:

Wrenches,

I searched the archives, but came up with nothing on this….

I have found a good supplier for reasonably priced stainless steel cable
ties and have been using them in place of black nylon cable ties for
supporting cables, PV wires and micro-inverter wires to the mounting rails
and such.  I feel better knowing the wires under the array are supported
this way rather than with plastic/nylon cable ties, for which I tried but
cannot get a manufacturer to guarantee will last 20+yrs.

A colleague is questioning this method (SS ties) with the concern that over
time the (albeit small) movement in the wires and/or expansion/contraction
of the rails could result in the stainless steel cable ties cutting thru
the wire's insulation and then…..

I have heard this concern before from others as well.

The way I see it is that the very popular stainless steel "S" cable clips
that hold wires to module frames have comparable equal sharp edges as well
and would pose the same risk, but there doesn't seem to be any concern
there.

I am wondering who else is using SS ties in place of nylon ones, and if you
are taking additional steps to protect the wire's insulation from the SS
ties?

Common sense abides, meaning don't wrap a wire around the SS ties so that
the wire has tension on the sharp edge of the tie.  Flat edge contact with
the wire only, the same way that you wouldn't run a wire across/around a
sharp cut edge of a rail or anything else.

Thanks,

benn

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