Guidelines for the Installation of Electric Fence for Excluding Black Bears

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The following has been prepared by the Ministry of Natural Resources and attempts to provide an overview of the subject for information purposes only. The Ministry does not guarantee the accuracy or completeness of the contents and assumes no liability for any consequences arising out of anyone's use of, or reliance on, the information. The Ministry does not recommend any particular manufacturer or product. However it is hoped that the information below will provide some assistance as you consider what specific solution will address your particular needs.

 

The installation of electric fence is an effective and relatively inexpensive way to prevent black bears from entering large areas such as landfills, agricultural sites and apiaries. Electric fence is easy to install and, although it requires some regular maintenance, is the most effective bear barrier for large areas.

 

  • Install a permanent fence with a minimum of six (6) strands of 12.5 gauge high tensile galvanized wire tightened to a minimum of 125 lbs. tension at 20 C. High tensile wire ensures that the fur of the bear is parted and the wire touches the skin directly. Place the bottom wire approximately five (5) cm from the ground, with alternating positive and negative strand, with the top wire at a height of approximately one hundred and ten (110) cm from the ground. Fence line preparation (leveling) and/or closer spacing of posts may be required to keep the bottom strand five(5) cm above the ground.
  • When the fence line is on loose or sandy soil, bears may dig under the fence (this also occurred when chain-link fencing was installed to exclude black bears). On such sites, install an apron (a six-foot chain link or page-wire fence attached to the posts of the electric fence and angled out and buried to a depth of approximately 1.5 m) or cement barrier at the base of the fence.
  • Attach the wires to fiberglass, wooden, or T-bar posts with insulators on the posts. Pound posts into the ground to a depth of 60 cm, rather than digging holes. On sites with < 60 cm of soil it may be necessary to drill into the bedrock and anchor posts with concrete. Space the posts a maximum of 7.5 m apart, closer on uneven terrain.
  • Choose an energizer of one (1) joule or larger, capable of delivering a minimum shock of six thousand (6000) volts. Electric or solar energizers are available. Check the voltage output of the fence regularly to ensure it is functioning properly. Secure the energizer in place or store it in a locked building to prevent theft.
  • Connect the first (bottom), third, and fifth strands to each other and the negative (cold) terminal on the charger, and the second, fourth, and sixth (top) strands to each other and the positive terminal on the charger, using insulated wire. Alternating hot and cold strands ensures the bear still receives a shock when there is poor conductivity between the bear's feet and the ground.
  • Ground the system using three (3) 16mm ground rods, 2-3 m deep and spaced at least three (3) m apart, connected to the negative output terminal of the fence charger by ground clamps. Where possible, locate the ground rods in a moist area. Consider longer ground rods on very dry sites, or ground mats on sites with exposed bedrock.
  • Install a lightning diverter to channel lightning strikes into the ground rods to prevent damage to the energizer.
  • Electric gates can also be installed where required.
  • Choose fence materials approved by the Canadian Standards Association (CSA) or Underwriters Laboratory (UL).
  • To prevent vegetation from growing up beneath the fence and touching the strands, which can drain power, partially bury geotextile cloth (landscaping cloth) along the fence line prior to post installation, or apply glyphosate herbicide (e.g. Roundup©) along the fence line.
  • Post warning signs to identify the site as electrified.
  • Ensure the fence is operational during the entire bear season (from April 1st to November 30th unless environmental conditions, such as snow depth, dictate otherwise).
  • Walk the perimeter of the fence at the beginning of each active season and regularly (at least weekly) thereafter to check (1) for evidence bear activity, particularly entry points or attempts to dig under the fence, (2) damage to the fence, and (3) wire height and tension. Clear vegetation and other objects that may short-out the fence.

 
 

Matchedash Waste Transfer
Station, Simcoe County.
Photo by: Jeff Schosser,
Ministry of Natural Resources

 
 
 

Matchedash Waste Transfer
Station, Simcoe County.
Photo by: Jeff Schosser,
Ministry of Natural Resources

 
 
  The electric fencing around
this 10 acre Ramara Township
corn field is powered by a
solar-powered energizer
which can provide a 7000
+ volt charge over several
kilometres of multi-wire fence
line. Crop depredation was
severe at this site in 2003
and in 2004. In the fall of
2005 the fence was erected
to protect the farmer's field
against black bears and other
wildlife. Initial results indicate
that electric fencing works and
is a viable tool in protecting crops. Photo by: Jeff Schosser, Ministry of Natural Resources


Install electric fence early in the season so that a bear receives a strong, negative experience the first time it attempts to access the area. It is much easier to keep bears away from an area if they receive a shock before they have a successful feeding experience. Bear activity in landfill sites typically peaks in July and August but may extend for months prior to and after that period.

 

In cases where there is no apron installed and bears dig an entryway beneath the fence, filling in of entry points and other low spots along the fence line with large cobble (15 - 30 cm stones) or logs may be required. Electrified ground mats can also be placed at entry points or spots where the bottom strand is higher than the recommended 5 cm, to deter bears from trying to dig or crawl under the fence at these points. An additional strand of charged wire running out 12 - 18" (30 - 45 cm) from the fence, and 8 - 12" (20 - 30 cm) above the ground can increase the change of a bear receiving a shock if it attempts to dig under the fence. These measures should be implemented immediately if bears gain entry to the fenced site.

 

NOTE: Where applicable follow all manufacturers' instructions when installing electric fencing or components or contact a knowledgeable electric fence installer prior to installing a fence.

 

NOTE: The information provided contains certain suggestions which are provided as a matter of courtesy for information purposes only. The Ministry of Natural Resources assumes no liability or responsibility, and makes no warranties, express or implied, statutory or otherwise, respecting the accuracy, currency or completeness of the information contained herein or its effectiveness to achieve a particular purpose. In no event will the Ministry be liable or have any obligation whatsoever for any damages or losses of any kind (including without limitation personal injuries or death) resulting in any way from any errors, inaccuracies or omissions in this information or the ineffectiveness of this information to achieve any particular purpose. The Ministry does not recommend any particular manufacturer or product.

 

TO REPORT BEAR PROBLEMS: contact the Bear Reporting Line at:
1-866-514-2327  (TTY) 705 945-7641

In a life-threatening emergency, call your local police or 911.

 

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