STAFF When swath grazing on frozen ground, or in areas where getting a good ground is difficult, sometimes a bipolar fencing system is a better option.
Instead of running a single positive wire and a negative ground, a bipolar system uses two above-ground wires. First, a single ground rod is hooked up to a yellow terminal on the fencer, which activates the bipolar function, then the positive wire is attached to the red terminal and the other to the green negative terminal.
“So, we’ve got two wires, one with 5,000 positive volts on one wire and 5,000 negative volts on the other,” said Rob Davidson, a Powerflex fencing dealer, who explained fencing theory at a grazing tour in Manitoba last year.
“If you touch both those wires, you get a 10,000-volt jolt. You’re really going to slap that cow.”
Bipolar fencing was originally designed for use with six-wire fences for species such as sheep and goats, but the system can be used with two wires for cattle. Running two wires is more cumbersome, however. That’s because the two wires have to be close enough so that the animals touch both at the same time, yet far enough apart that they never touch.
“It’s similar to the way a stock prod works, with positive voltage on one prong and negative on the other,” said Davidson.