problem with an Electric Fence

Pknellie

Member
Livestock Farmer
Hi. I've been using an electric fence for many decades with out any significant problems. Using 240 volt PEL with 2.5mm high tensile wire for about 1.5 Kilometers.
Recently my new neighbour installed an electric fence on our boundary using good quality standoffs and connectors. However he has put in two runs @ 200mm and 500mm off the ground using about 15mm poly-wire for about 2 klm. He has used a separate energiser for each wire. These are medium duty low impedance and specify 9 - 20 gauge wire only. They are self contained solar with lead acid battery (cheap Chinese he says). It states it's good for 5-8 kilometers. So much for the stats now for the problem. It doesn't work and he asked me for help
I don't want to advise him what I think is wrong causing him to spend more money unless I'm reasonably sure (my experience has not been with his kind of stuff).
When I test the output of the energiser I get 5.6 kV and zero amps but when I connect it to the poly-wire it drops to 2.8 -3.2 kV and still zero amps. At about 1 klm it drops to 0.8 kV. I find no evidence of a short either physically of continuity testing. Added the amps stay at zero. Question are the energiser units two weak for the job or the poly-wires two light or both. Or am I missing something? I would be grateful for your help.
Pknellie
 

holwellcourtfarm

Member
NFFN Member
Hi. I've been using an electric fence for many decades with out any significant problems. Using 240 volt PEL with 2.5mm high tensile wire for about 1.5 Kilometers.
Recently my new neighbour installed an electric fence on our boundary using good quality standoffs and connectors. However he has put in two runs @ 200mm and 500mm off the ground using about 15mm poly-wire for about 2 klm. He has used a separate energiser for each wire. These are medium duty low impedance and specify 9 - 20 gauge wire only. They are self contained solar with lead acid battery (cheap Chinese he says). It states it's good for 5-8 kilometers. So much for the stats now for the problem. It doesn't work and he asked me for help
I don't want to advise him what I think is wrong causing him to spend more money unless I'm reasonably sure (my experience has not been with his kind of stuff).
When I test the output of the energiser I get 5.6 kV and zero amps but when I connect it to the poly-wire it drops to 2.8 -3.2 kV and still zero amps. At about 1 klm it drops to 0.8 kV. I find no evidence of a short either physically of continuity testing. Added the amps stay at zero. Question are the energiser units two weak for the job or the poly-wires two light or both. Or am I missing something? I would be grateful for your help.
Pknellie
Certainly sounds like significant resistance in the poly wire.
The energisers are an unknown as well.
What's the earth like?
 

Pknellie

Member
Livestock Farmer
Hi. The earth is to a dedicated gal star post and also to the main fence plain wire. Seems ok. I think to take up the slack they have wound the Poly-wire tightly around some insulators. If it were resistance alone I can’t see why the kV would drop just after the connection to the energiser.
 

holwellcourtfarm

Member
NFFN Member
Can you disconnect one energiser completely then test the other wire?

I'm wondering whether the wires are inducing voltage in each other ave causing the problem. It's highly unusual to have 2 energisers running wires in such close proximity.

I do know some of the voltage loss in our system is due to voltage induced in the our boundary fence barbed wire from the field around the hot wire. I can get 2kV drop in under a km, even with a hefty mains energiser (12kV output at 16 Joules).
 
I do know some of the voltage loss in our system is due to voltage induced in the our boundary fence barbed wire from the field around the hot wire. I can get 2kV drop in under a km, even with a hefty mains energiser (12kV output at 16 Joules).
OOI, how close is the powered fence line to the barbed wire??

I ask, as I am looking at replacing a length of 3 strand electric fencing for pig netting, with a top electric fence wire, to use as a lambing paddock. Slightly concerning on the induction issue you describe!
 

Pknellie

Member
Livestock Farmer
Can you disconnect one energiser completely then test the other wire?

I'm wondering whether the wires are inducing voltage in each other ave causing the problem. It's highly unusual to have 2 energisers running wires in such close proximity.

I do know some of the voltage loss in our system is due to voltage induced in the our boundary fence barbed wire from the field around the hot wire. I can get 2kV drop in under a km, even with a hefty mains energiser (12kV output at 16 Joules).
I hadn’t considered induction. I’ll try that thanks.
 

Pknellie

Member
Livestock Farmer
OOI, how close is the powered fence line to the barbed wire??

I ask, as I am looking at replacing a length of 3 strand electric fencing for pig netting, with a top electric fence wire, to use as a lambing paddock. Slightly concerning on the induction issue you describe!
The poly-wire is on 200mm star post stand offs
 

holwellcourtfarm

Member
NFFN Member
OOI, how close is the powered fence line to the barbed wire??

I ask, as I am looking at replacing a length of 3 strand electric fencing for pig netting, with a top electric fence wire, to use as a lambing paddock. Slightly concerning on the induction issue you describe!
It's a 2mm high tensile hotwire about 4 inches below the top stand of barbed wire and 4 inches above sheep netting. The power loss would be a big deal if the energiser was battery powered.
 

Pknellie

Member
Livestock Farmer
I hadn’t considered induction. I’ll try that thanks.
Can you disconnect one energiser completely then test the other wire?

I'm wondering whether the wires are inducing voltage in each other ave causing the problem. It's highly unusual to have 2 energisers running wires in such close proximity.

I do know some of the voltage loss in our system is due to voltage induced in the our boundary fence barbed wire from the field around the hot wire. I can get 2kV drop in under a km, even with a hefty mains energiser (12kV output at 16 Joules).
I disconnected 1 wire at a time and shut down that energiser and found no differences in the voltages from when they’re both running at the same time.
The voltage still drops dramatically when I connect the energiser to the poly-wire.
 

Sid

Member
Livestock Farmer
Location
South Molton
Certainly sounds like significant resistance in the poly wire
This 👍

Compared Gallagher,Hotline and old own brand one.

The own brand the resistance was massive compared to Gallaghers. Complete waste of time and I heard the wires in it became brittle very quickly , Animal welfare issue as well.

I did point it out to them, but fell on deaf ears.

Don't know what the new own brand range is like.
 
It's a 2mm high tensile hotwire about 4 inches below the top stand of barbed wire and 4 inches above sheep netting. The power loss would be a big deal if the energiser was battery powered.
Thanks.

Something to be thought about.... In my case, I use a mains unit, BUT, the power drop could be an issue as the 300m fence in question is the lead out to another area of fencing.
 

holwellcourtfarm

Member
NFFN Member
Thanks.

Something to be thought about.... In my case, I use a mains unit, BUT, the power drop could be an issue as the 300m fence in question is the lead out to another area of fencing.
Our energiser kicks out 12kV with no load. Our fence tests at 8.5 kV just now with around 2 miles of fence connected but much of that is with the perimeter hotwire close to barbed and net as described above and some shorting to hedge. It's still plenty to maintain cattle respect so I don't worry. It'd be a no-go with a battery unit though.

Ideally I'd re-fence the boundary as just permanent electric but it's not worth the time and hassle (we should be moving within the year).
 

Pknellie

Member
Livestock Farmer
I disconnected 1 wire at a time and shut down that energiser and found no differences in the voltages from when they’re both running at the same time.
The voltage still drops dramatically when I connect the energiser to the poly-wire.
Our energiser kicks out 12kV with no load. Our fence tests at 8.5 kV just now with around 2 miles of fence connected but much of that is with the perimeter hotwire close to barbed and net as described above and some shorting to hedge. It's still plenty to maintain cattle respect so I don't worry. It'd be a no-go with a battery unit though.

Ideally I'd re-fence the boundary as just permanent electric but it's not worth the time and hassle (we should be moving within the year).
Thank you people for your input. I will pass on all your thoughts. My take on it all is that the poly-wire is being run beyond its capability and that the Chinese solar exciters are also not powerful enough for the job. That’s what I’ll pass on.
Pknellie
 

Mc115reed

Member
Change the earth garuntee it will sort it… I’m just wrapping up a 1800m field of 2 strands of poly so that’s 3200m of poly ran on a 2 joules rappa 12v battery energiser it was giving out 11KVA all around and I just clipped the earth onto exsisting stock netting that was down 1 side of the field already but half knocked over
 

Top cereal and oilseed growers honoured at the Yield Enhancement Network Awards 2021

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Despite an average growing year for most crops, many growers managed to go above and beyond their predicted max yields, with Lincolnshire grower Tim Lamyman taking the top spots for his wheat yields and his world record breaking winter barley yield.

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