Electric Fence Components
While electric fence designs and materials may vary with each fence project, there are a few main components to an electric fence system.
The main components are:
Energizers
An energizer is the power source for an electric fence. The energizer stores energy and delivers pulses of electricity through the fence system. The amount of stored energy is measured in joules. A joule is the single most important factor in choosing an energizer that is adequate to exclude grizzly bears (which will also exclude black bears).
Types of Energizers
AC energizers (plug in): AC energizers plug-in directly to a 110-volt outlet (a standard household outlet). If power is available near the fence site, this is the best energizer option.
DC energizers (battery operated): DC energizers are operated by deep-cycle batteries (6- or 12-volts). DC energizers require more maintenance than AC energizers, as the batteries must be regularly recharged for the fence to maintain optimal performance. This energizer type can be ideal for fence sites away from a power outlet.
Solar units (when no power available): Solar units consist of a solar panel attached to a DC energizer and battery, or come as a single unit with a built-in energizer and battery in an enclosed case attached to a solar panel. This energizer type can also be ideal for fence sites away from a power outlet. The location of the solar unit should receive enough sunlight to ensure that it will maintain sufficient charge for the battery.
When choosing an energizer to deter grizzly bears, be sure the energizer has a minimum of the following:
Joule rating of 0.7 - 1.0 joules or 7,000 volts or higher
0.7 – 1.0 stored joules or,
0.5 – 0.7 output joules
Pulse rate of 45-60 pulses per min, or once every 1.0-1.5 seconds
Low impedance energizer
For larger fence projects, you will also have to consider not only a minimum joule rating, but an energizer that is capable of electrifying a larger area and powerful enough to deliver an adequate charge over a longer distance. Additionally, your grounding system on your electric fence will be essential to getting the most out of your energizer. The grounding system is as important as the energizer in getting sufficient power to the fence.
AC-powered energizer
Solar-powered energizer
Grounding System
Without adequate grounding, an electric fence will be unable to deliver an appropriate shock to an animal. To complete an electric circuit, electricity must return to the energizer. This is accomplished with a grounding/earthing system. A grounding system is installed in the soil to attract and gather the flow of electricity and deliver it back to the energizer. For an electric fence to be effective, a grounding system must be big enough in relation to the energizer and soil moisture conditions. Follow the energizer manufacturers specifications for grounding the energizer and fence for your fence type and conditions.
Components of a grounding system:
Ground rods
Ground rod clamps
Ground wire
Ground rods
Ground rods receive and carry the energizer’s electricity from the soil back to the energizer. The length of the ground rod needed depends on the energizer’s output joule rating, as well as the soil conditions. Ground rods should be driven in the soil near the energizer to a depth of at least 3- 6 feet. It is necessary to drive ground rods as deep as possible so that the rod is in contact with the greatest amount of surface area, which will facilitate the flow of electric current back to the energizer.
Moist soils will need a minimum of 3 feet of ground rod per joule of energy output. For drier regions like the West, it is recommended to have at least 6-8 feet of ground rod per joule of energy output. Ground rods should be made of galvanized steel and have at least a ½-3/4 inch diameter. Multiple ground rods can be used and connected together in areas with rocky soils or sites where the rods cannot be driven deep enough. Space ground rods 10 feet apart and connect them in a series using ground wire and ground rod clamps.
Correct grounding: 6-8 feet of galvanized ground rod per 1 joule energy in energizer
Ground Rod Clamps
For connecting the grounding system, ground rod clamps and ground wire are needed. For securing ground wire connections, use one ground rod clamp per ground rod to secure the connection between the ground rod and ground wire.
Ground Wire
Use galvanized steel ground wire or insulated burial cable wire for connecting ground rods together for your system. Ground wire will also be used to connect the energizer’s ground terminal to the ground rod system. In some fence systems, a ground wire is included in the fence wire design to increase the effectiveness of the grounding system. See the Introduction to Electric Fencing section for an example design of a fence with alternating hot (live) wires and ground wires.
Ground rod clamp
Ground rod
Ground wire
Insulated burial cable
Wire
Types of Fence Wire for Electric Fencing
Electric Wire for Permanent Fences
Galvanized smooth steel wire is stronger than standard fence wire and best for permanent high-tensile fence designs. Aluminum wire is highly conductive, lightweight wire and can also be used for permanent fences. Both galvanized smooth steel and aluminum wire should be 12-14 gauge
Electric Wire for Temporary/Seasonal Fences
Turbo wire or polywire consists of multiple strands of aluminum or stainless steel wire braided within temporary fencing wire. It is flexible, strong, and can be unrolled and rerolled multiple times without breaking, making it ideal for temporary or seasonal fences. Avoid polytape or polybraid, as it has been shown to be less effective for bear exclusion.
Insulated Wire
For connections and buried wires, use insulated wire or insulated cable specifically designed for electric fencing. Insulated wire can be used to connect the energizer to the fence hot wires, connect the hot wires together in a series, and for connecting two sections of fence together, such as under gates. Insulated wire can also be used in locations where it might come into contact or cross uninsulated wire, causing an electrified wire to ground out.
For wires that will be buried underground (i.e. under gate openings), use heavy duty double-insulated wire that is 12.5 gauge. If vehicles or heavy machinery will use the gate or drive over the buried wire, the wire can be buried in conduit pipe to provide additional protection.
The type of fence wire used in electric fencing varies, depending on if the fence is permanent or temporary. Wire for permanent electric fences should be made of galvanized smooth steel or aluminum. Smooth steel wire is strong and durable, and a great option for high-tensile fence designs. Aluminum wire is lightweight and easy to use, but will break with constant or repeated bending. Permanent electrified wire should be 12-14 gauge in size. For temporary, portable, or seasonal fencing, consider using a temporary fencing wire such as polywire, or electric fence netting wire kits. Polywire is flexible, strong, and can be unrolled and re-rolled multiple times without breaking.
Galvanized high tensile electric fence wire (top) and insulated wire (bottom)
Other Wire Tips
Do not over-tighten the wires, as you want a flexible fence system that allows for impacts, including from wildlife, vegetation, or snow overloading.
Do not energize barbed wire. Animals can become entangled and trapped.
Electrified wires should be hung on the outside of the fence when deterring wildlife, compared to on the inside of the fence when containing animals such as livestock.
Posts
The type of fence posts used in an electric fence will vary, depending on budget and if the fence is permanent or temporary.
Types of Fence Posts
Wood fence posts are best for permanent, high-tensile fence designs. Treated wood posts hold up best. They should be set several feet into the ground
Fiberglass posts are best for temporary fence designs. They can also be used in permanent high tensile fence designs when reinforced with stronger fence posts for corners, braces, and end posts.
Composite posts are best for temporary fence designs. They can also be used in permanent high tensile fence designs when reinforced with stronger fence posts for corners, braces, and end posts.
Metal T-posts can be used in temporary and permanent fence designs. However, it’s best to avoid or limit the number of metal T-posts used when possible, as the metal may cause grounding issues if wires come into contact with the posts. Metal T-posts are best used for smaller fence projects, such as bee yard fences.
From right to left: a wood post, metal T-post, fiberglass post, and composite post
Fences can be designed to use a combination of posts (i.e., treated wood posts for corners and braces, and mix of wood posts and composite posts for the fence line). This can be helpful if trying to reduce fence costs. If fence cost is not a limiting factor, an electric fence built with treated wood posts will be the most effective fence design and last the longest.
Avoid metal or steel posts whenever possible in electric fence designs, as it can cause bleeding of the voltage in the fence and reduce its effectiveness and/or increase grounding faults.
Post Spacing
Spacing between posts may depend on the type of posts being used. When setting posts, choose a spacing that will allow you to keep your wires at the correct height from the ground. For an effective fence that holds tension of a high tensile fence system over time, in general, we recommend spacing posts 10-15 feet apart. Steep and uneven terrain will need to be considered and may require additional posts and shorter spacing.
Insulators
Insulators hold electric wires in place, keeping the wire from contacting the post. Insulators are commonly made of plastic or ceramic, which are nonconductive materials. There are various types and styles of insulators available, made for different posts and uses.
Insulators by Post Type
Most often, the type of insulators used will depend on the type of posts used in the fence. In-line post insulators include the following:
Wood post insulators (claw insulators, extension insulators, donut insulators)
T-post insulators (claw style, reverse T-post, extension insulators, cap insulators)
Fiberglass and composite posts insulators (clip insulators)
Insulators by Use
Specific insulators are designed for corner posts, end posts, and gate posts where wire sections end.
End post and gate post insulators (bull nose strainers, ceramic strainers, wrap around tubing insulators, heavy-duty lag-bolt insulators)
Corner posts (regular in-line post insulators, heavy-duty lag-bolt insulators, wrap around tubing insulators)
Gate-hooks (double-eye bolt insulators)
Insulators by Length
Insulators come in a variety of sizes and lengths to help customize the distance the insulator holds the electric wires offset from the fence posts.
For most in-line posts, a standard short insulator holds the wire 2 inches offset from the post—a sufficient distance.
If there is existing wire on the fence, look for insulators that will hold electrified wires at least 4-6 inches away from any existing wire. Extender insulators can extend the offset wire further from the posts, between 2-5 inches away. For electrified wires added to the outside of woven fence wire or wire panels, extender insulators can give more spacing between the woven fence wire and the electrified wires.
For fence designs that include a ground wire return system (i.e., an alternating hot and ground wire electric fence), the ground wires (-) may be directly attached to a post without an insulator, as the wires do not need to be insulated from the ground. If you are not using an insulator for the ground wire, be sure to still staple or secure the ground wire in place on the post to ensure it does not come into contact with the electrified hot (+) wires. For a uniform look in the fence wires, insulators can be used.
Ring insulator
Lag bolt corner insulator
T-post insulators, which may vary in style depending on the direction the post is facing
Wood post claw insulator
Accessories
Wire Connection Accessories
Nicropress sleeves: These are used to connect two wires together to create a permanent connection between the wires (i.e., connecting strands of hot wire together).
Wire taps: These are used to connect a wire to an existing strand of fence line for a permanent connection (i.e., when you already have the fence wire up and need to connect a wire to an existing strand or jump wires together). One end of the tap is open to allow for easy installation over the wire you are connecting to.
Ground rod clamps: These are used for securing ground wire to the ground rods in the ground system.
Wire Tightening Accessories
In-line wire tighteners: These are used for tightening in-line wires. They can be installed without having to cut the fence wire, and are useful in permanent electric fences, as wire may loosen slightly over time.
Fence strainers: These are used for tightening and joining electric fence wires. Strainers can also aid in reducing strain on posts.
Gripples: Gripples are a versatile accessory for joining, tensioning, repairing, and terminating wire on electric fences. They can be used to splice two wires together, including connecting and tensioning two opposite strands of wire on an electric fence, as well for tightening fence wires.
Gate and Wire Accessories
Gate insulated handles: Various custom gate handles are available to customize fence gates.
Cut-off switches: These are used to turn off power to sections of the fence (i.e., turning off the fence gate wires while accessing the gate, or the lowest hot wire if obstructed by vegetation or debris).
Various other accessories are available to customize and assist with offsetting wires for gates on electric fences, as well as innovative solutions such as drive over mats.
Energizer Protection
Energizer protective box: Depending on the energizer type (AC or DC/solar) and location, you may want to consider items to protect the energizer from outdoor elements.
Lighting diverter: For large-scale permanent electric fences in areas that may be prone to lightning strikes, a lightning diverter can help protect the energizer if lightning strikes the fence.
Fence Maintenance
Voltage meter fence tester or fault finder: A voltage meter or fault finder is used to check the voltage on the fence wires and at the energizer. This is an essential tool to help ensure the electric fence is working and maintaining sufficient voltage, as well as to identify faults or grounding issues in the fence. A voltage meter provides only readings on fence voltage. A fault finder provides additional information including amperage, the flow/current of amperage, and the direction of the fault to make locating faults easier.
Electric Fence Warning Signs
Adding signs to the fence can be a useful safety measure that informs others the fence is electrified.
Various accessories are available to customize an electric fence design for your particular fence and personal preference. Explore supplies in local fencing stores, check fencing catalogs, or look online for more information. Here are some commonly used accessories:
Gripple and gripple splicing tool
Wire cut-off switch
Lightning diverter
Wire sleeve
Open wire tap