Friday, March 26, 2010

What distance can your energizer power?

How far should you fence with an Energizer?

The distance of fence which an energizer can power is a hotly debated topic. The reason for this is largely due to the discrepancy between the distance you SHOULD fence and the distance you CAN fence with a particular energizer.

Most manufactures will claim that for one JOULE you can power up to (10) ten kilometers of multi strand fence. While these claims cannot be disputed, experience has shown that in practice, this is not ideal and often not practical.

For example, Gallagher claim that the Gallagher Smart Power MX7500 energizer which has an output energy of 57 Joules can power 160 kilometers of multi-strand fence. Similarly Stafix claim that a M36 energiser which puts out 36 Joules of energy can power up to 360km of multiwire fence. These claims are based on fences in New Zealand conditions that have no vegetation or other power leakages.

Other than the “up to” qualifying statement, there are two important factors that need to be borne in mind here. The first is that New Zealand has particularly high rainfall when compared with many other parts of the world such as most parts of Africa and the Middle East. The resultant moist soil conditions have a positive effect on earthing which is crucial to power fencing. The second factor is that the fence needs to be clean of vegetation. Once again, in environments where farming is carried out intensively, keeping fence-lines clean may be practical, but in environments where the vast majority of electric fences are used to control wildlife and cattle which are extensively ranched, fences are generally not free of all vegetation.

It is in these more arid and extensive conditions where it should not even be attempted to try and push these energizers to the distances claimed by the manufacturers. The first reason for this is that for the fence to be effective, fence hygiene has to be impeccable. The second is that if there is a fault on the fence, the entire fence is compromised.

It therefore makes more sense to use more energizers powering shorter distances of fencing. The energizers will then have surplus power to overcome the load caused by growth of vegetation and a dead short on the fence will not affect the entire fence. There is however a cost implication to this which forms the basis of the counter argument to this practice. If the cost of keeping the fence clean is considered, together with the value of the property and stock being protected or managed by the fence, the cost of an additional energizer or two is relatively very small.

For example, the cost of veterinary fees, immobilizing drugs and possibly the hire of a helicopter to recover a single rhino or buffalo which has broken through an underpowered or compromised fence is far greater than the cost of a Stafix M36 energiser. To try and stretch an energizer to its maximum therefore makes little sense and will probably not amount to a saving in the long term.

It should always be remembered that the energizer is the heart of the system and that the greater the effect on the animal, the more effective the system. So before you design your power fence system, contact your electric fence installer to get the right advice on how far you SHOULD fence with an energizer in your area.