Fence Fast is a component that converts mains or battery power into a short high voltage pulse that is sent along a bare wire. The other end of the wire is connected to a metal rod implanted in the ground, a.k.a. a ground system, that waits dormant until the animal touches both the fence and the ground. This closes the circuit causing an electric shock that deters the animal from touching the fence again.

The shock can feel like a jolt or a sharp involuntary contraction of the muscles. It is not deadly and the effect only lasts for about a second or two, but it is enough to discourage animals from trying to climb over or under the fence.

Powered Protection: A Comprehensive Guide to Choosing and Installing Your Electric Fence Kit

Using an electric fence requires a component called the power energizer that sends a small electrical pulse along an insulated fence line about once a second. The other end of the fence is connected to a ground system of metal rods buried in the ground that waits dormant until an animal contacts both the fence and the ground system. The energizer creates a circuit by releasing this pulse and an animal that contacts both the fence and the ground system completes the circuit and receives a shock.

The fence wires must be totally insulated from any other conductive material (such as grass, soil, rocks or metal) and should not loop back on itself. In the past it was a common practice to use a hose clamp holding a piece of copper wire to the t-post, but newer fence energizers use galvanized or stainless steel terminals that are less likely to cause a dangerous electrical short. Dry vegetation can also act as an insulator and does not generate current.