Definitions Of Terms
Low Impedance: Gallagher models are the latest state-of-the-art Low Impedance design which allows more shocking power to be delivered to the fence. Gallagher fencers will effectively charge a wider range of fence conditions and lengths with less power loss due to weeds and brush contacting the charged fence wire. Gallagher Low Impedance fencers will shock through wet weeds and brush and will shock to end of fence.
Fence Load: Electric shock is a product of voltage and current (amps) and it is the current that provides the power of the shock that the livestock feel. Voltage provides the electrical pressure that makes the current flow. Fence load is vegetation (weeds, vines, etc.) contacting the charged wire which creates a short to ground through the weed. The more weeds touching the charged wire, the greater the fence load becomes, causing voltage on the fence to drop and current (amps) to rise. Open Circuit is when the fence charger is operating with no fence load. 500 ohm load equals approximately 5 miles of medium weeded fence. 100 ohm load equals approximately 5 miles of heavily weeded fence.
Joule Rating: The joule is a measurement of heat in British Thermal Units (BTU's) or foot-pounds Energy. The distance a given weight can be moved in a unit of time, or the amount of heat that is generated for a specified time, equals a joule. i.e. a joule is equivalent to .7378 foot pounds of .0002778 watt-hours (approximately 1 watt second). The joule does not measure the effectiveness or safety of electric shock. The joule is a mathematical equation of (Voltage x Amps x Time). The longer the "on-time" of the pulse, the higher the joule rating will be even though a longer "on-time" is less effective and less safe to use. It is important to point out that Underwriters Laboratories (U/L) and Canadian Standard Association (CSA) do not recognize the joule as a measurement when applied to electric fence chargers. We agree with U/L and CSA that the joule rating is not an accurate way to measure the effectiveness of any fence charger, however, we have provided the above joule ratings so you will have a basis of comparing gallagher with other brands which do rate their fencers in joules. Gallagher joule ratings are based on the lowest and highest rating that model will produce based on varying fence conditions.
NOTE: Fence conditions (fence load) constantly varies 24 hours a day and there are no two fences which are the same. The joule rating of any electric fence charger constantly varies as the fence load varies. No one can tell you accurately the joule rating on your fence without actually measuring it on your fence.