Many farmers and wildlife reserves install electric fences to keep animals in or thieves out. Ordinary citizens also install electric fences around their properties in an effort to improve security and sleep peacefully at night.
However, an electric fence is only doing its job when it is in could repair and maintained properly and regularly. Test your fence from time to time and do not turn off the siren when it sounds continuously, this is a tactic used by criminals in the hope that you will be irritated and switch it off.
Keep your fence free of vegetation; this is often the cause of false alarms. A blade of grass with dew on can set off the siren. Inspect your fence regularly, once a month is a good idea. Test the fence with a piece of wire attached to a wooden surface, something like a wooden pole. This way you cause the short yourself and you can find the problem area, if there is one. If you hear your fence making a tic-tic sound, it does not mean the fence is working, it only means the energizer is working. Other faults on a fence include jumpers and loops that touch another wire, broken bobbins and wires, and earth loops that touch one another.  
If the electric fence is around your domestic property you should make doubly sure that it is working order, otherwise there is no point. Do not touch the wire directly though; it will hurt, it is supposed to do just that.
Incorrectly repaired or installed electric fences can be the cause of many a false alarm. Many installers know something about the electric fences they are installing but do not have in depth knowledge of electrical equipment. When they bridge a fence, they do it to stop the alarm and not to repair the problem, which means it can happen again. Find a reputable installer who can do the installation correctly the first time and who will find the cause of false alarms using the correct test equipment.