Energized fences

Excluding deer and other wildlife from your garden with energized fences

Properly designed and maintained energized fences are effective at reducing deer damage to gardens. Energized fences are inexpensive to maintain and can last for many years. However, an energized fence is not a physical barrier against deer entry. An energized fence acts as a psychological barrier which some animals will continually test for an entry location. It is important that an energized fence be properly installed, maintained, and powered at all times. For best results, install and energize your fence prior to spring planting.

NOTE: Check local fencing ordinances before investing in an energized fence. They are prohibited in some municipalities.

Fence design

The four critical components of an effective energized fence are:

1. a high voltage, low impedance energizer capable of delivering a minimum of 5000 volts to the fence under all conditions;
2. an adequate electrical grounding system;
3. proper wire and post spacing; and
4. monitoring of the fence power status with a digital voltmeter.

Energizer

• A high voltage, low impedance energizer delivers a short (0.003 second), painful, but safe shock to deer. The short pulse will not set fire to plants contacting the wires, nor injure humans or animals.
• Energizers may be powered by 110-120 volt household current, a 12-volt battery, or D-cell alkaline batteries.
• Household current (110-120 volt) is the most reliable and maintenance free power source for most gardeners. Electrical costs are minimal. Deep cycle marine batteries are recommended for 12-volt energizers. Solar panels are simply a recharging system for battery powered energizers. Use a 110-volt energizers for gardens that require year-round protection.
• Install 110-volt energizers in a shed, garage, or other building and bury insulated underground cable from the energizer to the fence. Protect your 110-volt energizer with a single outlet surge protector. Hang D-cell energizers directly from the fence wire.
• Install the energizer and grounding system prior to installing posts and wire. Energize all fence wires.
• Remember, the shocking power of the fence deters the deer. The fence is the delivery system; it is not a physical barrier and will not be effective unless constantly energized (turn the fence off only for maintenance).

Grounding

• Use a minimum of three, 6-foot galvanized steel grounding rods. Avoid copper. Additional rods may be necessary in sandy soils. Drive ground rods so that approximately 3-4 inches remain above the surface to attach the ground cable from the energizer.
• Place ground rods at least 10 feet apart in the wettest soil available.

Wire and Posts

• Recommended wire spacing for deer from the ground up: 12", 20", 28", 36", and 44".
• Use 8-foot by 4-inch treated wood posts with insulators at the corners. Place the wide end of wooden posts in the ground. Lean corner posts slightly away from the pull of the fence. Back fill and tamp wooden posts. You will need at least 46 inches of the post above ground.
• You may use electroplastic or polywire, seventeen gauge steel wire, or light gauge twisted steel cable. Polywire with a minimum of nine strands of stainless steel wire is recommended. Polywire is easier to use than steel wire. However, it is more costly and not as durable. Use light gauge steel cable or wire around gardens that require year-round protection.
• Adjust wire tension by hand pulling to remove visible sag, and hold with knots on the ends. Spring-type gate handles also serve to maintain tension. Use small tension springs with twisted steel or seventeen gauge wire.
• Use porcelain or heavy duty plastic insulators on wooden corner posts.
• Wooden posts with insulators, fiberglass, or 1/2" Schedule 40 PVC plastic pipe are recommended for line posts. To prevent shorting, avoid using steel posts with insulators.
• Place line posts no more than 15 feet apart.
• Many gardeners prefer to leave a 4- to 6-foot wide area between the fence and garden o maneuver wheelbarrows and tillers.

Voltmeter
A voltmeter is essential for monitoring the fence power and trouble shooting. Digital voltmeters are available from energized fence manufacturers.

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