Electric Fence With Large Acreages
The second design is meant for commercial agricultural situations.
The design, developed in Pennsylvania, is given the name Penn State
Vertical Electric Deer Fence1.
The fence has five wires. The bottom wire must be approximately 10
inches (25 cm) from the ground, while the remaining wires are spaced
at 12 inch (30 cm) intervals above each other, making the fence 58
inches (145 cm) high. Wider spacing is not recommended.
The key materials are: high-tensile smooth steel wire (200,000 psi,
12 ˝ gauge), special accessories (indicator springs, in-line wire
strainers, crimping sleeves instead of knots, tube insulators, and
wrap-around insulators) to maintain 250 lb. (114 kg) wire tension, and
high voltage, low impedance energizers.
High-tensile wire absorbs the impact of a deer, falling trees, or
branches and farm equipment without stretching or breaking. The
tensioned wire and high voltage ensure good shocking power.
Penn State Vertical Electric Deer Fence
The amount of compression of the indicator spring determines when
250 pound (114 kg) tension is reached. Wrap-around insulators used at
corner or end posts have galvanized metal inserts that prevent the
fence wire from cutting through the insulation under high strain.
Each straight length of fence begins or ends at an end post, corner
post, or gate post. These are thicker and longer and are set deeper in
the soil than other posts. Construction of brace assemblies at these
points is probably the most important aspect of a high-tensile fence
because these strong points support the tension on the wires.
Corner Post Construction
End Post Construction
Line posts can be smaller and spaced 50 to 60 feet (15 to 18 m)
apart on level terrain where minimal lateral, upward, or downward
forces are expected. Removing underbrush and debris along the line,
and grading off humps, eliminates many construction problems and
results in a fence that is straighter and easier to maintain. An open
site about eight feet (2.5 m) should be left outside the perimeter of
fences; this ensures that deer will be walking as they approach.
Leaving woody fence rows or bushy cover just outside the fence might
encourage a deer to jump. In curves or on uneven terrain more posts
are needed to maintain the 10 inch (25 cm) bottom wire spacing. The
fence must be adequately grounded and have approximately 7.5 yards (7
m) of grounding rod or pipe in the soil. Rather than one long rod,
this implies several shorter rod lengths connected by wire. Space
ground rods at least 10 feet (3 m). A buried sheet of galvanized
roofing also makes an excellent ground.
Electric fences require regular inspection and maintenance. Even
with high-voltage, low impedance energizers, weeds growing against the
fence must be removed. The weeds, especially if wet, can drain enough
voltage to reduce effectiveness.
Fences should also be checked after lightning storms.
The Penn State Vertical Electric Deer Fence is well past the
experimental stage and has proven to be an effective deterrent to deer
in Nova Scotia and other places. If built properly, it will give good
For cost and further technical information contact a farm supply