OK, here is the results of my investigation today. First, the blue
coloring of tie wraps
(note - the industry calls these ?cable ties?) are nothing special. We
also get them in other colors, such as, green, orange, red, gray, yellow,
aqua, and white. The reason for the colors is for separating different
system cable bundles from others. Here at our nuclear plant, we have all
wires/cable installed inside conduit or cable trays. When the
wires/cables were installed, it was decided to use the different colored
cable ties to bundle separate system?s cables together, thereby saving
maintenance time when troubleshooting system problems across the plant
site.
For outside use, which requires UV protection, we use standard commercial
cable ties that have a UV rating. Still these cable ties are nothing out
of the ordinary. They are made by Panduit and Thomas & Betts, easily
purchased through any electrical warehouse or via Newark Electronics.
For use inside the reactor containment building (where radiation is
potentially the highest), we use cable ties that are made of Tefzel.
Tefzel is a material that does not easily breakdown when subjected to
radiation and other harsh environments. And, if it does melt, due to
intense heat, the byproducts do not contaminate or affect other critical
components.
Here is what I found when I looked at Thomas & Betts
Technical/Specification Catalog
(1400 pages!):
Types - Rating Nos.
Standard Nylon - 11333
Weather Resistant Nylon - 41333
Fire Retardant Nylon - 11234
Wx Resist. Nylon 12 - 41421
Polypropylene - 11321
Wx Resist. Polyproplene - 41321
Tefzel - 54444
Stainless Steel - 55555
Respectively, each digit represents - UV resistance, Radiation, Low
Temp., High Temp,
Flammability. 5 = most suitable, 1 = least suitable. NOTE - stainless
steel is the best.
Here is the T&B quote on cable ties for special applications: ?Natural
nylon cable ties are excellent performers in most application. However
to answer your cable tying needs in more severe environments, T&B offers
ties in a variety of special materials. ... The ties are available in a
range of lengths and tensile strength ratings. .... For example, if your
application is in an extremely cold environment, 3 materials will answer
your need: Tefzel, Nylon 12, and stainless steel. If you require high
tensile strength, then stainless steel is your best choice. Where high
strength is not required, Nylon 12 might be your choice as it is the
least costly. .... This information is based on data provided by the
manufacturers of the specific materials listed and is provided only as a
guide. ... As each application may vary, testing should be conducted by
the user in the intended environment.? In looking at the description of
the various stainless steel cable ties, it appears that you would need a
special tool for using T&B?s ties. I could not find a Panduit catalog;
however, I did look at their cable ties that were listed in the 1998
Newark Electronics catalog and noted that they have the Pan-Steel series
(Type MLT) that can be easily installed by hand or tool. Plus, the Type
MLTC are plastic-coated. Depending on size and rating, prices ranged
from just under $1 to over $2 each. Although this is expensive when
compared to the other types, once installed they should not breakdown due
to sunlight, weather, etc.
In further investigation, I talked with one of our plant engineers about
the use of nylon
cable ties in the plant. The color of the Tefzel ties that we use are
aqua. There is
currently no maintenance plan to replace the commonly-used black UV-rated
ties that are in outdoor locations. There has not been any cable tie
degradation problem noted in the 12 years that the Harris Nuclear Plant
has been in commercial operation.
The bottom line: For the best, cost no object, get the stainless steel
cable ties. For the
standard black type, easily hand-installed, get the UV-rated weather
resistant in either
nylon or Tefzel. But remember, get the name-brand ones from an
electrical supply
warehouse, not the cheap ones from your local hardware store, unless you
like climbing your tower more frequently.
BTW, I work at the Harris Nuclear Plant, New Hill, NC, and have no
connections with any cable tie companies.
73,
Henry Pollock - K4TMC
Raleigh, NC
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