Deterrents – Electric fencing

Electric fences provide a cost-effective means to prevent bears from entering campsites and from acquiring food from human facilities in residential, agricultural or industrial settings.

While management of odours will minimize the likelihood of a bear encounter, fences can prevent bears from receiving a food reward or causing damage in the event they locate the facility. Several types of portable and permanent fencing systems are available that have proven to be effective barriers for bears.

Electric fences must be properly installed and regularly maintained in order to be effective.

What should I consider when building my electric fence?

Properly installed electric fence prevents this grizzly bear from accessing garbage dump

• A fence charger that has a joule rating of more than 0.5 joules and delivers at least 5,000 volts should be used. Either a 12-volt portable system or a 110v AC power system can be used where AC power is available.
• The 12-volt systems work best with a 12-volt deep-cycle marine battery connected to a solar panel, which keeps the battery charged. A 12-volt battery can power a fence for several days or weeks without recharging, depending on the size of the battery and charger.
• The charger must be located within the fenced area to prevent damage by bears.
• The fence material should consist of metal wire or interwoven poly-metal wire.
• In areas with good soil conductivity, all fence wires should be "hot." Where the soil is dry, wires should alternate "hot" and "ground."
• The distance between posts is not critical as long as the wires remain at the indicated heights above the ground.
• A 120-centimetre (four-foot) ground rod pounded into the ground and attached to the grounded portion of the fence should be adequate at most sites. Water can be poured in the area of the ground rod in drier soils if required. The fence voltage should be tested regularly to ensure proper grounding.
• A gate can be constructed with the same materials and design and fastened with rubber fasteners. For permanent sites, an electrified cattle grate entrance can be used.
• Fences should be buffered by two metres on each side with vegetation controlled within this area to prevent electrical failure.
• The fence should be powered at all times between April 1 and November 30.
• For increased effectiveness, there are a variety of testers, sensors and alarm systems that can be added to electric fences.
• The fence should be marked with appropriate signs warning the public that electric fencing is a safety hazard.

What electric fencing is best for my facility?

• Permanent or long-term facilities (longer than one bear season) should be enclosed with a six-foot chain-link fence with either three strands of barbed on top surrounded by a four-strand electric fence or a seven-strand electric fence.
• Seasonal facilities (one bear season) should be enclosed with a seven-strand electric fence.
• Short-term temporary facilities (less than one bear season) should be enclosed with a four-strand electric fence.
• Remote facilities should be enclosed with a four-strand electric fence. Specially designed, light-weight fencing systems that utilize D-cell batteries and wire-mesh fencing material are available for use in backcountry situations.