electric fence

mugsyy

having a few problems with a mains electric fence

have it in this 4 years and up to know worked well but this year cattle keep going through it

disconnected the fence from the mains unit and tested with a electric fence tester and it is working fine, getting a reading of 6000 - 7000v.

Then cleared away any briars / whins etc that were close to the line and reconnected. Happy now there is nothing touching the line.

Now getting a reading of 2000v on the fence (tested on a few different points along the line and it reads the same)

just wondering is it normal for a fence to loose this much power or have I another problem (poor earth)?

If this is normal is 2000v enough to keep the cattle in or should i be looking at a larger mains unit?

any suggestions appreciated...

Markcheese

Is it a big enough fencer for the lenght of fence you have, is the earth connection for the fencer good enough?
Are you sure its not earthing off fence posts or if you have insulated wire going under gateways ect, or poor joints.
Can you break/disconnect the system down into sections or blocks , and then add the sections back on one by one to see if you can narrow down where theres a problem..

_Brian

What sort of wire have you from the unit out to the earth and fence. It needs to be double insulated steel wire. No copper wire should be used in any section to carry power.

Then check the earth. You should be able to put your hand on the earth bar and not get any shock if you get a shock then the earth has a problem. Ideally three earth bars a meter long each and a meter apart. The earths need to be in damp ground, not at the back of a wall or hedge where the ground is snuff dry. In really dry weather ours dry out and we run a hose round the earths for a few hours to moisten the ground.

Once there is no copper wire being used and the earth is good then I'd advise testing right at the end of the wire carrying out the power without it connected to the fence. Then add on sections as advised above to identify where the problem is.

mugsyy

_Brian wrote: »

What sort of wire have you from the unit out to the earth and fence. It needs to be double insulated steel wire. No copper wire should be used in any section to carry power.

Then check the earth. You should be able to put your hand on the earth bar and not get any shock if you get a shock then the earth has a problem. Ideally three earth bars a meter long each and a meter apart. The earths need to be in damp ground, not at the back of a wall or hedge where the ground is snuff dry. In really dry weather ours dry out and we run a hose round the earths for a few hours to moisten the ground.

Once there is no copper wire being used and the earth is good then I'd advise testing right at the end of the wire carrying out the power without it connected to the fence. Then add on sections as advised above to identify where the problem is.

Used the good insulated wire. have a feeling it could be the earth, will test tonight, thanks for advice.

lalababa

The 6-7kv suggests you have earth problems (rusty connections/ rusty earthing rod/ dry weather) as most fencers are 10-11kv, the 2kv suggests you also have grounding problems around the fence which can easily crop up. This senario always happens this time of year. ALL wire must only touch insulators and all bare wire must be at least 11/2 to 2cm away from any metal or wet wood. The odd bit of vegetation is not too bad.

blue5000

Another possibility is a cracked egg insulator near a strainer. Underground cable has failed here too, I run it through a length of hydrodare pipe. Do you have bryce spigots going through the strainers? Sometimes they earth inside the strainer, put your hand on the wood on a wet day and you'll find them.

Disconnect a section near the fencer and see what sort of power you have. Then gradually add a section.