Causes for shorts in Electric fencing??

Question

We are running 2 hot wires through insulated off-set brackets on a fence with total length of 1.2km using a 2km solar energiser. We have 3 earth stakes in the ground and attached back to the energiser. The fence is only charging to 3.8-4kv consistant through the length of the fence. There is no undergrowth touching hot wires or cracked insulators. Any thoughts ???

Answer 1

Well we found out that with ours the ground moles nibbled the wires.

Another thought is there a capacitor in the relay system?

Answer 2

Normally an electric fence needs earth spikes to reduce noise in the surrounding area. I would make sure the earth is correct. The earth should go all around the fence on the bottom. Then you get the outgoing and return wires.

The best thing to do is to first check your wires for rust on the surface. This will cause a volt drop. Then you look at all the joints and see if they are not oxidised. If nothing is evident then open all the joints and make sure that you know which is the outgoing wire. Get a fence volt meter and measure at the first join. You should get 8kV or 6kV depends on your unit. Then close the join and measure at the next open join. Carry on until you get to a section with a large volt drop. If it is gradual and you get to 4kV at the end then get a bigger unit.

Make sure where it goes in pipes and under ground that there is no contact to earth. There might be water in the pipe and a crack in the pipe.

Answer 3

How good is your grounding?

I know you said you have 3 stakes in the ground but placement, depth and location all play a major factor in getting a good ground.

Install some 8 foot ground rods a minimum of 6 feet apart, further apart the better. For these I usually put them under the eaves of a barn so the soil they are in will get lots of moisture.

Some fencers only come with a short little ground rod that can be totally inadequate if the soil conditions are bad. Having more of them is better but nothing like a big 8' rod or better driven into the earth.

If you really want to get creative you can look into chemical ground rods.

You can also run a grounded strand between the two hot strands and ground it ever so often on your fencing path.

Also are you using wire with an insulation rated for 5kV at any point where the wire penetrates a wall?

Your setup may not even do this but I've seen it more than once. People will put the fence box on the inside of a shed or barn to protect it then will feed a wire through the wall. Most times they'll grab some wire around the house that only has an insulation rating of 600V. Pretty soon this insulation will fail  and leave them with no power.

Answer 4

Sounds like leakage. Isolate sections at a time and see what happens.

Because the electric fence is a psychological barrier, it does not require great strength to be effective. However, it must be well designed and constructed to absorb some pressure from animals, snow and wind. The energizer must have enough power for the length of the fence and for the animals being controlled.

Answer 5

You have checked the battery electrolyte and load tested it ,the solar panel can cook the battery if the charging voltage isn't regulated depending on the size of it and the size of the battery (google morningstar)is the panel shaded at any part of the day?(google unisolar shade tolerant),do what Numbat said,