Science Questions

Do electric fences work like tasers?

When you touch an electric fence and get a shock; if you touch a mate they also get a shock. Why not a taser? Succubus Huntress, Second Life

Chris - I think it’s in the answer you gave, Dave.  The way a taser works is to put two probes with very high electrical potential which means there’s a big potential difference between the two probes.  Most of the current in the taser is flowing from one probe to the other probe.  But the fence works slightly differently in that it’s putting a wire (or a cluster of wires) at a very high potential relative to the ground so that animals that brush against the fence feel a current flowing from the fence, through them to ground.  That’s uncomfortable and it puts them off. 

If you put yourself in the position of that animal you are holding onto someone and you touch the fence then both you and the person you’re holding onto have a connection to ground.  You’re offering a path to ground for the electricity flowing through the electric fence.  Therefore there will be a current.  Unlike the taser which has got the two probes, each of them with a higher amount of potential relative to one another.  It’s the ground that is the low potential and the fence that is the higher potential.  It’s a slightly different situation.

April 2009