Electric fencing quotes from registered installers

How an electric fence works

An electric fence is a set of insulated wires carrying short, high-voltage pulses from an energiser. Anyone touching a wire completes the circuit to earth and gets a painful but non-lethal shock. The energiser also monitors the fence: if a wire is cut, shorted or earthed, it can trigger a siren or signal your alarm system.

The energiser is the heart of the system. Its output and the quality of the earthing decide how well the fence works, especially on long runs or where vegetation touches the wires.

Wall-top or free-standing?

Wall-top fences sit on brackets on top of a boundary wall or palisade, adding height and a deterrent to an existing barrier. They're the most common home installation. Brackets angled outwards make the fence harder to climb over from the street side.

Free-standing electric fences are a complete barrier on their own, built on posts at ground level. They're more common on farms, estates and commercial sites, and need more strands and a clear zone free of plants.

The certificate of compliance

Electric fences are regulated by the Electrical Machinery Regulations, 2011, under the Occupational Health and Safety Act. Installations must comply with the safety standard SANS 10222-3, and an Electric Fence System Certificate of Compliance must be issued by a registered electric fence installer: someone registered with the Department of Employment and Labour's chief inspector.

Every new electric fence system needs one. Fences installed before 1 October 2012 only need one if they're added to or altered, or when the property changes hands, which is why the certificate comes up so often when people sell a house. The electrical certificate of compliance for your house wiring doesn't cover the electric fence; it's a separate document.

Common upgrades and repairs

• Replacing a tired energiser with a more powerful or smarter unit, often with app notifications.
• Adding strands or raising the height to close gaps an intruder could use.
• Linking the fence to your alarm and armed response, so a cut wire brings a response rather than just a noise.
• Lightning protection. Lightning strikes on fence wires can destroy an energiser; diverters and surge protection reduce the risk, which matters most in thunderstorm-prone regions.
• Fault finding. Shorts from vegetation, broken insulators and corroded joins are the usual causes of a fence that keeps alarming or has lost its voltage.