Protecting a Barrier Horse Fence with an Electric Fence:
Obviously, the main fence element not needed in electric fences that protect barrier horse fences is fence posts–because insulators and the charged conductor can be mounted on the existing barrier fence.
Chargers: Choose a charger suited to the size of the enclosure. If the fenced-in area is small (surrounding a paddock for example) use a low-powered charger like 01-24A, 01-23, or 01-12 to avoid panicking the horses. If the fence is moderately long (enclosing a several-acre pasture) with little or no weed burden, consider using a more powerful but still modest charger such as 01-04, 01-09, or 01-15. And if the fence is very long (several miles around) with a substantial weed burden, do what you can to reduce the weed burden, but also consider using a powerful charger such as 01-06A, 01-11A, 01-22, 01-28, or 01-29, and plan on making frequent use of a fence tester like 04-04 or 04-07 to ensure that you have 4,000 volts on all parts of the line.
Insulators: If the existing fence is made of wood, use nail-on insulators for wood posts that extend in from the fence however far they need to extend in order to keep the charged conductor from touching anything that is not insulated (including wood). Five-inch insulators like 07-57 or 07-11 are fine, but they cost more than shorter insulators. If the small arms of the extender insulator do not hold the conductor securely enough, take an extra turn or so around the end of the insulator to make sure the conductor stays put; or, if the insulator doesn’t need to hold the conductor far out from the post, consider some other style of insulator that holds the conductor tightly (see product 07-59). If the barrier fence is made of vinyl, use wood screws to attach insulators like 07-53 or 07-54 to the vinyl posts. In most cases plan on placing an insulator on every post to prevent the conductor from coming into contact with any posts, and plan on using corner knobs like 07-13, 07-13A, or 07-68 at the corners instead of line insulators.
Conductors: Visibility is not an issue here, because the barrier fence is plenty visible; so one should avoid the wide polyconductors (polyrope and polytape), and instead should use polywire or heavy metal wire (14 or 12.5 gauge) to protect a barrier horse fence. The main advantage of polywire (products 02-10 thru 02-12B, 02-67. and 02-68) is that (in contrast to metal fence wire) it can be reeled up, stored, and used again. But heavy metal fence wire (such as products 02-75 thru 02-77) is a better conductor than most polyconductors, so it is well-suited to protecting and reinforcing long barrier horse fences. Both polywire and metal wire should be maintained under enough modest tension to ensure that the conductor does not come in contact with other portions of the fence–something that can be accomplished by mounting small circular tensioners (like product 08-04) on the line.
Grounding: If grounding conditions are good (moist ground most of the time, ground not hard frozen) use a single line of conductor (carried by a single line of insulators) to protect each part of the barrier fence (generally the top line of cross-members) that needs protecting. If grounding conditions are poor (dry or frozen ground) install two lines of conductor-bearing insulators a few inches apart (the two lines must not touch). Plan on hooking one conductor up to the positive terminal on your fence charger and the other to the ground terminal on the fence charger. So long as the two conductors do not touch, an animal will get a shock whenever it touches both conductors at the same time, regardless of the conditions on the ground. Even so, to promote maximum effectiveness in all seasons one or more ground rods (see products 06-01C thru 06-06) should be inserted into a generally moist area of ground near the fence. Attach one end of a wire securely to the top of the ground rod(s), and attach the other end to the wire to the ground terminal on the charger. PLEASE NOTE THAT NO PART OF THIS GROUNDED CONDUCTOR, GROUND ROD, OR GROUND ROD WIRE CAN TOUCH ANY PART OF THE CHARGED SYSTEM (positive terminal on the charger, hookup wire leading to the fence conductor, or the charged conductor itself) because that will short out the system, and an animal touching the active conductor (or both conductors) will receive no shock.
