October 11, 2014
The most commonly used materials for portable fencing are polywire and polytape. Both of these
materials are combinations of plastic strands and metal filaments. Usually the plastic component is
polyethylene and the metal is stainless steel. Other products are available that use fiberglass
strands for structure and aluminum or tin-copper alloy for the conductors. The main feature of
these products is that they are lightweight and require no tools for setup. Virtually no bracing is
needed to hold the fence and very light duty line posts may be used. The main limitation of the
poly products is the distance that they can be energized before the internal resistance of the fine
wire filaments used as conductors becomes restrictive.
Most polywire contains either 6 or 9 strands of conducting wires. The wires may either be stainless
steel or some alloy with higher electrical conductivity, such as tin-copper. The 9-strand stainless
steel can be effectively energized for distances up to ½ mile or 2640 feet. Beyond this distance,
voltage may begin to drop off. A 6-strand tin-copper product is usually more conductive than
9-strand stainless steel and may be energized for greater distances. The downside of tin-copper
filaments is they are not as durable as stainless steel. More strands of plastic in 9-strand
products also serve to increase the breaking strength and visibility of the product. Both 6 or
9-strand products may contain two or three color filaments, which greatly adds to the visibility
and longevity of the material.
Polywire is available in two different basic forms: twisted or braided. Braided polywire offers
several advantages over twisted products. Conductivity of any braided cable is greater than a solid
wire of similar gauge. This is because electricity moves along the wire surface, not through its
core. Braiding increases the effective surface area of wire. Braiding also increases strength
whether we’re talking about plastic string or wire. Braided polywire has significantly higher
breaking strength compared to twisted polywire. Added strength means greater longevity for the
product. Cheaper polywires end up being much more expensive than buying top quality polybraid due
to their much shorter life expectancy.
We now use gallaher Polybraid exclusively in our temporary fence situations.
Polytape comes in a similar array of options. Generally the cheaper the price, the fewer wires and
less durable the plastic. Polytape should be purchased on the basis of number of filaments and
quality of the plastic weave in the tape. A good polytape will have the visible appearance of good
stout strapping tape and contain at least 6 wire filaments.
Tape has the advantage of greater visibility when compared to polywire. The tape tends to flutter
in the breeze and attract animal attention and inspection. This generally leads to quicker animal
recognition and training to the fence. However, the same fluttering may cause greater wear of the
tape on metal post clips or insulators that will reduce the useful life of the fence. A good
quality tape should have a useful life of 5 to 7 years unless it is handles abusively. Polywire may
last up to 10-15
years with proper use. Each new generation of products has a longer useful life.