The Electric Fence is the same as a Fence, but is blue and when you are trying to cut it, it will electrocute you. (You will take 20 damage, and be sent to infirmary if knocked out.) They also electrify the ground tiles beneath them, which means that attempting to dig a tunnel through these tiles will shock the player. Note that the tiles below an electric fence are not destroyed by cutting tools, but are simply dug through like any other ground tile.
In The Escapists 2, electric fences bear electric sparks and shock you if you get too near.