HOW AN ELECTRIC Bear FENCE WORKS, page 1
All electric fences have two parts, an active part and an inactive part. The active part consists of the positive terminal on the charger, the insulated hookup wire (if there is one) connecting the electric fence charger's positive terminal to the conductor (metal wire, polywire, or polytape), and the actively charged conductor that runs along the fence. The inactive or “neutral” part consists of the negative (ground) terminal on the electric fence charger and everything connected to it. In the traditional setup using a ground rod, these inactive components are a wire connecting the negative terminal to the ground rod, the ground rod itself, and moisture in the soil running from the ground rod over to the fence.
The incoming bear gets a shock when it unsuspectingly serves as a unique bridge between these two systems. That is, when it touches the active wire a charge passes from the active wire through the bear’s body, through its feet, and out its feet into the water in the ground (dry soil cannot carry a charge but water can). Using this water, the charge travels over to the ground rod, up the ground rod, along the ground rod wire, and over to the negative terminal on the charger, thereby completing the circuit.
Typical materials for an electric bear fence, in this case a fence for protecting beehives (see kit 13-84-S2JPLUS) are shown below: