Making an Old Fence Work!

Good fences let you sleep at night! One of the biggest challenges when renting pastureland is marginal perimeter fencing.  It is very hard to justify the investment in new fencing if you are on a short-term lease.  One option is to install an electrified offset on the interior of the perimeter fence (Figure 1).  This works especially well with old woven wire fences.  The electrified offset 1) helps to contain livestock, 2) extends the life of the existing fence by keeping animal pressure off of it, and 3) provides a source of electricity for further subdividing pastures with temporary fencing.  Lastly, offsets can be easily removed and taken with you if the lease doesn’t work out.  

Since electric fencing is a psychological barrier (nothing likes to get shocked) it needs to deliver a knee bending, eye watering jolt preferably to the moist nose of the animal.  It is imperative that the animal’s first experience with electric fencing be a really painful one.  For this to occur, offsets need to be installed correctly.  If you take your time and install electric fencing correctly, it can be an extremely effective tool to control livestock.  If you cut corners and use cheap materials or materials not designed for electric fencing, it can be an extremely frustrating experience.  The objective of this article is to provide you with some practical tips for installing offsets that can effectively control livestock and extend the life of an old fence.  

Use good quality offsets.  Make sure that plastic components in the offsets that you use are UV stabilized.  Saving a few pennies now can result in a real headache as plastic components start to breakdown in the sunlight.

Use 170,000 PSI high tensile wire with a Class III galvanization.  This wire is corrosion resistant, able to be hand tied, and economical.  A good quality high tensile wire will cost about 2.5 cents/ft.  One installed, fence should be tensioned just tight enough to take the slack out.    

Mount offsets at nose height of the livestock that you are trying to control.  The height of the offset is important since your goal is to shock the animal in the face.  For cattle this will be around 30 inches off the ground.  

Use twist on offsets for woven and barbed wire fences.  The offsets consist of two galvanized legs that are twisted onto the existing fence holding the electrified offset approximately 10 inches from the existing fencing.  One advantage of these offsets is that they move with the existing fencing reducing the chances of the electrified wire coming in contact with the old fence (Figure 2).  They are also easy to install and take off.

Use wood post offsets at beginning and end of runs and on problem posts.  I like to use a more rigid wood post offset at the beginning and end of runs.  This helps to get the offset wire away from the existing fencing (Figure 3).  I also like to use these offsets on problem posts with in the run, like old railroad ties that have the existing fencing wrapped around them (Figure 4).  

Start and end runs with an end strain or bullnose insulator designed for high tensile fencing.  These insulators are designed for the tension exerted by high tensile fencing (Figure 5).  They are constructed of either reinforced UV stabilized plastic or porcelain.   If the electrified offset is close to the existing fence at the start and end of runs, install the bull nose insulator 4 to 6 ft from the end post.  

Use a good quality double insulated cable designed for electric fencing for lead-out, jumping wires or going underneath gates.  Never use residential wire for electric fencing.  This wire is designed to carry 120 volts NOT 10,000.   

Always place underground wires in protective tubing. Whenever a cable carrying current is run under the ground, always place it in some type pipe or conduit that will protect it from future damage. Wires going under gates should be buried to a depth of approximately 6 to 12 inches. If not protected, breaks will occur in these wires and these shorts can be difficult to find and repair. I like to use pvc electrical conduit and secure it to post with a clamp (Figure 6).  The larger the conduit, the easier it is to push the double insulated cable through it.  I prefer to use ¾ or I-inch piping in most situations.  I also like to drill a hole in an end cap just large enough to slip the wire through and simply push the end cap onto the conduit with NO glue.  

Make all connections with clamps. Loose connections result loss of voltage. Connections should NOT be wrapped, but rather clamped together with a high-quality clamp that is designed for high tensile fencing (Figure 7). Never use clamps that are constructed of dissimilar metals. Although economy clamps constructed of cast metal are sometimes available, they often fail upon tightening. Saving a few cents on clamps often leads to exponential headaches in the future.

Use a doughnut or bull nose insulator secured to a wood post to make gentle turns.  Gentle turns where the offset wire pulls to the inside of the pasture can be make using a doughnut type or bull nose insulator secured to a stable post (Figure 8).  NEVER use wrap around insulators.  They almost always fail prematurely resulting in hard to find shorts.  

Use heavy duty wood post insulators to make gentle turns.  Gentle turns that pull toward to the outside of the pasture can be made by securing one or more heavy duty wood post insulators to a stable post.  In cases where the offset wire is too close to the old fencing, a treated 2 x 4” can be secured to the post with deck screws and the insulators can then be screwed to the board (Figure 9).  

Use a high-quality energizer.  Energizers are the heart of electric fencing systems and are NOT a component that you should try to “save” money on.  If electrical service is available, plug in energizers are considerably more powerful and offer the best value in terms of cost to power ratio. For remote areas, solar or battery powered energizers are viable alternatives for smaller acreages. Power comparisons of energizers should be done using “stored energy” which is measured in joules.  One accessory that I cannot do without is an energizer that has a remote control that allows you to shut the fence off from anywhere.  Once you have one, you will wonder how you ever got along without it!   

Proper grounding is essential. For an electric fencing to work properly, current from the fence must travel through the animal into the ground and back to the energizer. The grounding system on the energizer works as an “antenna” to collect this current and complete the circuit. Most of the problems associated with low voltage on an electric fence are caused by a poorly constructed grounding system. Grounding systems should have a minimum of 3 galvanized grounding rods, 10 ft apart, 6 ft in the ground, all connected with a single galvanized wire running from the energizer. For very large energizers or very dry conditions more grounding rods may be needed.

The above tips will help you install offsets capable of controlling all classes of livestock.  However, for these offsets to work properly they should be kept “hot” at all times and vegetation below them must be controlled.  This means that someone, preferably not you, will be manning a string trimmer this summer! ~ Dr. Chris Teutsch. Based on article in Cow Country News.

Figure 1.  Electrified offsets can breathe new life into an old fence.  They control livestock, extend the life of an existing fence, and allow for further subdivisions using temporary fencing.   

Figure 2.  Twist on offsets are easy to install and remove and are ideal for older fences since they move with the fencing material reducing the chances of shorts.  

Figure 3.  Wood post offsets are more rigid making them a good choice to install at the beginning and end of runs where there will be more pressure pushing back against them.  

Figure 4.  Wood post offsets are a good option for getting the hot wire away from posts that protrude and are littered with old fence.

Figure 5.  The beginning and ends of runs should be terminated using a bull nose insulator designed for high tensile fencing.  

Figure 6.  Double insulated lead out wire going under gates should always be placed in a pvc pipe to protect it from breaks.  

Figure 7.  Make all connections using a high-quality galvanized clamp.  Wrapping wires results in loose connections causing voltage losses.  

Figure 8.  Doughnut or bullnose insulators can be used to make gentle bends in the offset that pull toward the inside of the pasture.  

Figure 9.  Gentle bends that pull toward the outside of the pasture can be made using heavy-duty wood post insulators.  If the electrified offset is too close to the existing fence, then a treated 2 x 4 board can be mounted to the post.