Electric Fencing

 


Note: Be sure to check your local ordinances regarding electric wire fencing to find out what is permissible in your community.

Electric fences are among the most effective deterrents. They can be constructed in a variety of configurations such as a baited, single strand or 5,7, or 9 wires pitched either horizontally or vertically. They are powered by high‑voltage, low amperage chargers that provide timed pulses of short duration. Deer quickly learn to avoid these fenced‑in areas. Electric fences are more of a "behavioral barrier" than an absolute barrier, which means that if they're not properly maintained (see Tips), deer will learn how to get through them.

If you have a small garden or area to protect, check with your local garden store because many sell electric fence kits that may suit your needs. Know that deer are quite resistant to electric shock due to their hollow, well-insulated hair, and the small, pointy design of their hooves which lessens the electrical impact. This is why they can often get through the horizontal wires of electric fences without feeling much of a shock.

 


Tips for Successful Electric Fences

  • Inspection and Maintenance: Fences must be regularly inspected and maintained to remain effective. Every week, check for broken wire and do a voltage check. Deer constantly test fences and if they get through once, it is much more difficult to recondition them.
  • Mowing: Vegetation must be cleared away—and kept away—from the lower wires or the wire may short out. Be sure to clear a minimum 10-15 foot buffer on the outside of the fence so deer see it and don't run through it.
  • Baiting: Many professionals believe that baiting with peanut butter or other lure is vital to make electric fences fully functional. Some fencing suppliers incorporate bait holders into their fence kits (see Premier 1 Supplies and DeerBusters products, Table 3). Peanut butter baits can be applied to aluminum foil strips each week (see diagram under “Peanut Butter Fence” but be sure to scrunch the foil around the peanut butter so it doesn’t flutter in the wind) or directly onto the electric wire/polytape. You want the deer to first taste the peanut butter, not to be scared of it. When the deer make nose-to-fence contact, they get an unpleasant jolt that conditions them to avoid the fence in the future. Clean off any old peanut butter so it doesn’t get moldy. [A recent publication (Craven et al, 2001) suggests that baiting may not be necessary.]
  • Leave Fence On: Leave the electric fence ON at all times to prevent deer from testing the fence when it’s off.
  • Chargers and Warnings: It is important to use a high quality energizer (or charger) that puts out 5000 volts. Chargers (also called energizers) are AC, battery or solar‑powered. How well a charger performs is dependent on its power output measured in "joules under load." To effectively repel deer, a good rule of thumb is that one joule of output from a charger will adequately power 3000 feet of fence wire. Check with your fence supplier to make sure that the charger is matched to the fence design and is appropriate for your needs (Kays 2001). And don’t forget to put up warning signs.
  • Repellents: For added deterrence, after deer have made initial contact with the fence, you can take strips of cotton and soak them in an odor repellent (Table 2). Hang the strips at regular intervals and reapply the repellent every month. The odor will help reinforce the negative impact of the electric shock.

 


Some Electric Wire Fence Types

Single-Strand "Peanut Butter Fence": This single‑strand fence design relies on a peanut butter or other “bait” being attached to the wire (usually through strips of aluminum foil hung from the wire with cloth adhesive tape) to reinforce a negative message. This fence is only 2 ½ feet high and most effective for small gardens and nurseries under 3 acres. Use 17-gauge smooth wire and attach to wooden posts (as illustrated, except be sure to scrunch aluminum foil around the peanut butter so it doesn’t flutter in the wind). The cost is under 15 cents per linear foot. DeerBusters sells a single strand, baited fence kit for properties under 4 acres. This kit has aluminum caps built into the fence design to hold lure, which makes bait application easier and “less messy.”

Polytape and Polywire Fences: These temporary fences are highly portable and best suited to home gardens, small nurseries, and orchards under 40 acres that don’t have severe browsing pressure. Polywire is composed of 3, 6, or 9 strands of metal filament braided with stands of colored polyethylene. Polytape is wider and more expensive, yet flutters in the wind more so it may not last as long as polywire. It is best to purchase materials with the least electrical resistance (ohms/1000 feet) to prevent loss of voltage due to long distances. Polytape or polywire fences are usually suspended 30 inches off the ground by fiberglass rods at 2‑4 foot intervals. It is recommended that a second wire be added to increase effectiveness, so one is at 18 inches and the other at 36 inches. These fences can last 15+ years and be installed for less than 25 cents per linear foot. Many kits, which include all materials, are available so checking fencing suppliers (see Table 3) and your local garden store.

3-D Scented Anti-Deer Fence: This new electrified rope system sold by Premier 1 Supplies takes advantage of the fact that deer have limited depth perception. Two electric fences are spaced 3 feet apart from each other to create somewhat of a 3-D effect. The outer fence has one rope with scent caps attached (which contain cotton to hold an apple scent lure) to attract the deer. The inner fence has 2 strands of electrified rope. Both fences are electrified by the same energizer. The whole system costs under 35 cents per linear foot to install and will last 7-10 years. The apple scent is sold separately for $5 an ounce, and a few drops are used per application. It is recommended that the scent be refreshed every 10-14 days.

Electric-Bait Kit: Deerbusters sells a single-strand electric fence kit that comes with “deer pops” (aluminum caps that hold scented lure), posts, corner supports, polywire, a tester, and warning signs. The kits come in either solar or plug-in designs. The plug-in is recommended because it’s more powerful. This kit is for small (under 4 acre) gardens. Cost of kit ranges from $225-315 depending on size of area to be covered.

Electric Spider Fence: This relatively new fence is mainly used to protect domestic animals or crops. It contains a 5‑wire system that is only 4 feet tall and uses a light 16‑gauge wire. It relies on fiberglass posts that maintain wire tension and spacing. It does not require bracing but requires wood posts on the corners. It comes with an electrified gate. Note: this is a semi‑permanent fence (lasts 10‑12 years), and not as durable or long lasting as woven wire. Baiting with peanut butter (as outlined above) is important to make this fence fully effective. The cost is under 50 cents per linear foot.

High-Tensile Vertical Fence: These fences deter deer effectively as long as a height of 8 feet is achieved and the wires are correctly spaced so deer don’t go through them. We recommend the design using 9 high-tensile wires (Craven et al, 2001 --- see diagram). Deer will try to go under or through these kinds of fences, so the bottom wire should be no more than 2 inches off the ground (strung very tightly) with additional wires spaced at 8-9 inch intervals. The materials include high-tensile, smooth wire, (12 ½ gauge) and an energizer that puts out 5000 volts at a maximum pulse. This fence can last as long as 25 years. Installation and materials range from 50 cents to $1.50 a linear foot. Some people run an additional, baited strand of hot wire (such as Premier Fence’s Intellitape or Intellirope) outside the fence to ensure that deer encounter electrified wire and get a shock before attempting to go through the vertical fence. The main problem with vertical fences is that deer tend to get through them, which is why this new design (9 high tensile wires, strung no more than 9 inches apart) replaces the older recommendation of a 7-wire vertical fence, with wires 10-12 inches apart (Craven et al, 2001).

Slanted 7‑Wire Fence: This 12 gauge fence is a variation of the vertical fence and generally more effective because it confuses deer. It must be slanted at a 30‑degree angle to the ground. Because of the slanting effect, the deer see a much more formidable barrier than really exists. It measures only 5 feet high but 8 feet wide, and contains an electrical "incentive" which increases its deterrent value. This kind of fence costs about $1.50‑2.00 per linear foot. The disadvantages are that it’s more difficult to maneuver around this slanting fence to do maintenance (mowing, etc.) due to its wide berth. More importantly, far fewer people use this fence because it “requires strict adherence to construction guidelines concerning rigid fence corner assemblies and fence configurations (Craven et al, 2001).”

 


Peanut butter bait
Electric fencing
Unbrowsed due to electric fencing