An electric fence is setup as a barricade, and is used to dissuade people or animals from crossing a boundary. The electric fence delivers painful or sometimes even a lethal electric shock to anything that comes in contact with it.

The electric fence was first described in 1889, as a defensive weapon in Mark Twain's novel 'Yankee in King Arthur's Court'. In the early 1930s, farmers used electric fences to control livestock. One of the earliest known applications of the electric fence was created in 1936-1937, by a New Zealander named 'William 'Bill' Gallagher Snr'. It was built out of a car's ignition coil and a meccano set. The Gallagher Group of companies is still involved in electric fencing today. The Electric fence creates an electrical network, when it comes in contact with a person or animal. A high-voltage pulse is generated though a device called a power energizer that converts power into electricity. One terminal of the power energizer generates an electric pulse across the fence at duration of around one pulse per second. The other end of the power energizer is connected to a metal rod called the ground rod. When a person or animal comes in contact with the fence, the electric circuit is completed, thus resulting in an agonizing electric shock. The intensity and fatality of the shock depends on the voltage and electric current being used.

Electric fences are being widely used for security purposes by both private as well as government bodies. Lethal electric fences are setup in prisons to prevent convicts from escaping. Modern day electric fences have monitoring devices that can detect an intruder rather than directly electrocuting the animal or person in contact with it.