Learning How to Use a Fence Tester

All fences require routine maintenance. I guess that’s a pretty bold statement coming from an ol’ fence guy, but truthfully correct. I don’t care if you are talking about barb wire, electric, board or pipe fences – they will all require that you periodically make some routine checks and repairs to keep it in good operational condition. We all know that most physical barriers must be maintained and tight. If neglected, they will soon become useless and need replaced.

With the mere mention of electric fencing, some people immediately think of all the maintenance that invariably goes along with it. It doesn’t and shouldn’t have to be that way. Most problems on electric fences are generally “human”. If you did a reasonably good job with the initial installation and used a good powerful energizer as well as installed adequate grounding – then maintaining it should not be all that big of a problem. Being an electric fence post salesman I can’t go on here without saying that if you use insulated line posts; you will have even less maintenance to deal with.

Here's a quick how-to. First, find a section of fence that is hot and get the baseline amperage reading (the 0 reading above is uncommon, most fences will have some leakage).

Then connect a set of jumper leads to the post and wire to create a short.

Then take a reading downstream of the short. It should return to the baseline amperage reading that you took before the jumper leads were connected. This tells you that the short - the alligator clip in this case - is somewhere between the two readings.

Take a reading upstream of the short (between the source of the power and the short). Notice that there is now a large amperage reading showing.

So, what do you need to monitor or keep your electric fence working properly over the years? The best item that you can get is a good fence tester. They come in all colors shapes and sizes. Some read voltage only and others will read current and voltage. Some will also have remote control features that allow you to turn off your energizer from anywhere on the fence. Most run off of an internal (replaceable 9V battery).

Personally I feel very strongly that you shouldn’t have electric fence if you are not going to spend a few dollars for a management tool. You cannot just assume that the fence is working – you need to know how much voltage is on ALL of your fence wire. So, at the very least, you will need a voltmeter that will show you a voltage reading.
In recent years there has been a lot of improvement and additions in management tools. Some of them now also read current. These are referred to as, Fence Compass, Fault Finder, Smartfix and so on, depending on brand. They will read voltage, current and direction of current. In essence, they will help walk you to a short or problem. The current reading will normally be shown as Amps. A fence with no shorts will read 0 Amps (if there is leakage, the amps will, so to speak, flow out thru the short). Most meters will read up to 100 Amps. With practice, the severity of the short can usually be determined by the number of Amps.

Each manufacturer will usually include an instruction sheet on usage. Below is the manufacturer’s instructions for the Stafix Fence Compass describing how to find a short by monitoring your meter readings:

“Start near the energiser’s leadout wires. Move down thefence line following the arrow away from the energiser. Take readings at regular intervals and at any junction points. The previous current reading is shown briefly in the top right corner of the screen so that you can compare the readings. If the current reading suddenly falls, you have gone past a fault. Retrace your steps to find the fault.”

This seems like a pretty simple process of taking readings to find a short. But I have been amazed at how many people purchase these tools and still don’t know how to use them. Once they are “shown” you can see the light go off in their heads, but until then these are just numbers on a screen.

I remember once at a pasture walk, someone had a meter and asked if anyone could show him how to use it. There were a lot of comments and opinions expressed but you could tell that the guy still didn’t have a clue. So I offered to do a little demo for him. I hooked up a set of jumper leads with alligator clips to create a short from a hot wire to steel t-post. We took readings before and after the short. Once he could visually see the readings – he immediately understood how it worked. Don’t be intimidated or afraid to ask questions.

I would suggest that when you purchase a meter that you read the instructions first, but follow up with some actual experimenting with it. Go ahead and create some shorts, and then take some readings so that you can visually see how the readings are generated. Once you do this it will all make good sense to you.

Once you master your management tool it will save you a lot of walking looking for problems. Most people get very good at this. When you understand your system, you will be able to find and repair any problems in rather quick order. Not that it is foolproof, as I myself have from time to time stood and scratched my head, talking to myself, over meter readings.

Another thing to keep in mind is that during the high vegetation months, you may get high amp readings from grass and weeds. If you are showing a high amp reading at the beginning of the system and they gradually reduce as you walk your fence – what you are probably seeing is an accumulation of many small grass shorts that add up to a lot of fence load over distance. So, when you have a lot of grass on your fence wires you will likely read a lot of amps that will drop off as you progress down the fence line, rather than a large major short.

Good luck and learn your meter! If you run into a difficult and confusing situation; call me on my cell at 417-260-1277. I’ll be happy to help if I can.


About Gary Duncan

Gary has been active in the fence business for over 15 years. He also raises Highland cattle in a management intensive grazing system and was the first person to market the PasturePro post back in 2005. He enjoys discussing all things grazing and is the main contributor to the blog.
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