Installing Electric Fence Posts
Post Length and Insertion Depth: Electric horse fence height ranges from an absolute minimum of 3 feet (for single-strand portable fences) to a rarely exceeded maximum of 6 feet. However, most portable and temporary electric horse fences are roughly 4 feet tall, and most permanent electric fences designed to serve as the outer barrier for an equine area are 5 to 6 feet tall. Knowing these heights, one must still know how far the fence posts must go into the ground in order to determine the post length needed. Thin (3/8 and 1/2-inch) fiberglass posts are typically inserted about a foot into the ground. Thick fiberglass posts and steel T-posts (whether on not their above-ground parts are to be sheathed in 5-foot vinyl sheaths) should be inserted 18 inches to 2 feet–unless heavy clay soil and a deeper frost line raise the potential for frost heaves, in which case they should be placed below the frost line. Both thick fiberglass posts (which have pointed ends and come with drive caps) and T-posts can be driven in with a hammer or sledgehammer, though it is generally more convenient and faster in the case of T-posts to use a manual post driver like product 15-05. Beware of having an assistant steady the top of a tall post by hand, because the driver can do major damage to a hand as it descends. Thick wooden posts should be driven deep into the ground with a mechanical post driver (a massive piece of equipment that requires a truck). The depth of insertion for wooden line posts ranges from a minimum of 30 inches (where deep frost is not a problem) to 48 inches or however far one must go to get below the frost line. Wooden corner posts should go deep–typically between 42 and 48 inches–and should in all cases extend below the frost line.
Post Braces, Cement Footings, and Earth Anchors: Any corner, end, or gate post placed under significant sideways stress, even if it is set relatively deeply into the ground, needs to have some way to counter that stress or it may tilt. This tendency to tilt can be countered by installing braces, earth anchors, or a combination of the two. Sometimes no extra devices are needed (if the sideways stress is moderate and the post is a massive wooden post), and sometimes the corner, end, and gate posts for a fence system (like the fiberglass Common Sense Fence™ system) come with their own braces and earth anchors. However, if one is using steel T-posts at the corners, ends, and gate openings of a large fence, then installation of braces or earth anchors is advisable. If one is planning to encase the T-posts in vinyl sleeves, it should be noted that this sheathing is not compatible with braces or earth anchors. Therefore, 4 x 4 pressure-treated wood posts or larger round wood posts should be substituted for vinyl-clad T-posts requiring braces or earth anchors. If desired, these wood posts can be sheathed in vinyl or painted white to match the vinyl sleeves.
In many cases where braces or earth anchors are used to support T-posts it is also desirable to install cement footings. That’s because the brace post(s) supporting a corner or end T-post may be forced into the ground by stress instead of providing much support for the corner or end post–unless the feet of both the support post(s) and the corner or end T-post are embedded in cement. And likewise, instead of supporting a T-post, an earth anchor may simply serve to press it into the ground unless the post has been encased in a cement footing. The following procedure is one good way of installing a cement footing, something that is a little bothersome, but not nearly so involved or costly as renting a massive motorized post driver to install thick wooden posts.
How to Install a Cement Footing: Dig a 10 to 12 inch diameter hole with an auger or manual post-hole digger. This hole should be 3 or more feet deep if there is deep winter ground frost, and 2 feet deep if frost is not a problem. If the hole is 3 feet deep fill the bottom 12 inches with large rocks (softball size to hardball size), place the post in the hole, and measure to ensure that the top is the desired height above the ground, adding or removing rocks as necessary to obtain the proper height. If the hole is 2 feet deep follow the same procedure without initially placing rocks but adding rocks if necessary.
