Tuesday, October 20, 2015

How an electric fence works

Well, how does an electric fence work?
  1. The fence energizer sends an electric pulse through its positive terminal to the fence. 
  2. The fence then carries this pulse until an animal comes in contact with the fence. 
  3. The pulse travels through the animal and into the soil/ground. 
  4. The pulse is then absorbed from the soil back into the energizer via the ground rod system. 
So where do the terms joules, voltage and ohms come into play?
  • Joules is the volume of electrical energy in a pulse (think gallons, pints etc. in water systems). 
  • Voltage is the measure of pressure upon the pulse to move from A to B (similar to PSI in air and water systems).
  • Ohms is the resistance to electrical flow (constrictions in these systems). Higher ohms reduce the felt pulse.   
Points to consider:
For a fence to be effective, we suggest a minimum of 3000 volts. This means the fence needs to have reasonable high pressure (voltage). But that's just half of it. The other half being the size of the pulse, which is measured in joules (read as released, not stored, on fence energizers).

High pressure (volts) behind a large pulse (joules) results in a deterring shock when the fence is touched by an animal. The smaller the joule (output) the smaller the potential shock and vice versa. Also, the lower the voltage the smaller the felt pulse.

If bigger is better (or so it seems), why do we recommend .5 joule units?
For fences with low resistance (ohms) and have high voltage (at least 3000v), a .5 joule energizer is enough to deter animals. Longer fences with more resistance need more joules in order for pulse to be felt.