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 <[email protected]>
*To:* RE-wrenches <[email protected]>
*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 <[email protected]
<mailto:[email protected]>> 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
[email protected] <mailto:[email protected]>
*From:*[email protected]
<mailto:[email protected]>
[mailto:[email protected]
<mailto:[email protected]>] *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
[email protected] <mailto:[email protected]>
817.917.0527
NABCEP Logo
*From:*[email protected]
<mailto:[email protected]>
[mailto:[email protected]] *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 <[email protected] <mailto:[email protected]>> 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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