Electric fencing relies on an animal’s ability to learn, once they associate touching it with an unpleasant shock, they will avoid it in future. So the most important period is the first week after erecting the electric fence. Check it daily to ensure it is working well, so your animals are more likely to receive a shock during this initial learning period. Thereafter, you need only check the fence once a week or so – even if the power is off for a period, the animal will already have learnt to avoid it.
At each inspection, check:
- The connection between the battery and the fence energiser. Look for any sign of displacement, interference from animals, or corrosion
- The connection between the energiser and the earth rod
- The connection between the energiser and the electric fence
- Using a Digital Voltmeter or a Fault Finder, check the pulse at each end of the electric fence, and on each conductor wire on multi-wire fences. It should read at least 5kv
- Walk the fence line looking for signs of damage to insulators or evidence of ‘arcing’ (charring of the insulation material) which indicates a breakdown of insulation. If the fence energiser is on, you may hear arcing as a regular click, or in low light you may see sparks
- In electrified netting, check the horizontal wires at 10m intervals and the connections between rolls of netting
- Make sure you control surrounding vegetation to avoid leaks that reduce the voltage
Understanding Fence Load
Along the course of a typical electric fence there are many factors that can divert or impede the flow of electricity – these factors make up what is known as the ‘fence load’.
The most common cause of a high fence load is vegetation touching the electric fence – this draws current away from the line, reducing the power available to give the animal an effective shock. While larger, better quality fence energisers will power through a certain amount of vegetation, and animals can do a fair job of grazing beneath the wire, you cannot rely on either – control excess vegetation with a strimmer or broad-spectrum herbicide, such as glyphosate.
Other factors contributing to fence load include:
- Poor quality insulators
- Cracked or damaged insulators
- Sagging or broken wire
- Rusty wire
- Poor joins in wire
- Inadequate energiser for your fence length
- Insufficient earthing
Wet weather can magnify many of these problems, possibly leading to the fence ‘shorting out’. This happens when all the electricity produced by the energiser leaks away, or is prevented from flowing effectively.