Electric fence, how far through flex cable?

5312

Member
Location
South Wales
I would like to put mains electric fence around the farm. The main obstacle are the buildings and yards.

The proper lead out cable is quite expensive but we have loads of flexible cable and twin and earth cable.

I have read somewhere that you should only use the lead out cable but I don't know what the problem would be with the flex.

Does anyone know if you can use the flex and how far it could be used? Have some runs of 100m where we need insulated wire.
 

neilo

Member
Mixed Farmer
Location
Montgomeryshire
I was led to believe the insulation on mains cable breaks down over time as your putting 10,000v through it, not 240v, although a lot lower current of course. If that’s true, you would end up getting leakage through the cable, rather than getting almost full power at the other end.
 

Dry Rot

Member
Livestock Farmer
I think conductivity will depend on (a) the conductivity of the metal, and (b) the cross sectional area of the wire, and (c) it's length (if I remember my school boy physics correctly).

So lead out cable is usually aluminium and fat so satisfying the two main requrements. Yes?

The cross sectional area of twin and earth, even though you'll use all threee wires is not going to be great but copper is a good conductor (and cheaper). Why not try it and see? Surely easy enough to use a multimeter to test the restsitance of a length of each and compare while still in a coil? There are probably statistics somewhere and if they can't be found, ask the manufacturers? I do think the special "under gate" and "lead out" cables are a bit of a con when you can put ordinary fencing wire through water pipe to insulate it (but obviously not your 100m lengths). Could you not put 2.5mm high tensile high up and out of reach?
 

Paddington

Member
Location
Soggy Shropshire
We have runs of 50m and bit the bullet and used co-ax lead out cable which hopefully was a one off job 15 years ago. We put the co-ax through alkathene pipe under ground and gateways, sealing the ends with silicone. Hopefully anyone in the future seeing a blue pipe will assume it's a water pipe and not stick a spade through it.
 

neilo

Member
Mixed Farmer
Location
Montgomeryshire
I think conductivity will depend on (a) the conductivity of the metal, and (b) the cross sectional area of the wire, and (c) it's length (if I remember my school boy physics correctly).

So lead out cable is usually aluminium and fat so satisfying the two main requrements. Yes?

The cross sectional area of twin and earth, even though you'll use all threee wires is not going to be great but copper is a good conductor (and cheaper). Why not try it and see? Surely easy enough to use a multimeter to test the restsitance of a length of each and compare while still in a coil? There are probably statistics somewhere and if they can't be found, ask the manufacturers? I do think the special "under gate" and "lead out" cables are a bit of a con when you can put ordinary fencing wire through water pipe to insulate it (but obviously not your 100m lengths). Could you not put 2.5mm high tensile high up and out of reach?

Water pipe definitely breaks down and leaks voltage over time, so not ideal for threading ordinary fencing wire through, especially underground. I would always put lead out wire under a gateway through a pipe, but only for protection.

We used to make post insulators out of 6” lengths of water pipe years ago, stapled onto wooden stakes to fence most of the farm for cows. After a few years (Maybe decades ?) a lot would ‘crack‘ through to the post in a wet time.
They were only cheaper than buying packs of proper insulators if you made good use of cheap child labour (me at the time).
 

jonny

Member
Location
leitrim
I would like to put mains electric fence around the farm. The main obstacle are the buildings and yards.

The proper lead out cable is quite expensive but we have loads of flexible cable and twin and earth cable.

I have read somewhere that you should only use the lead out cable but I don't know what the problem would be with the flex.

Does anyone know if you can use the flex and how far it could be used? Have some runs of 100m where we need insulated wire.

Don’t bother with the twin and earth cable it’s only good for less than 1000 volts and the joints where you connect to the fence lines will corrode in time Better bite the bullet and use proper lead out cable and bolt every joint too not wrap around. Have 2 miles of 2 strand of ht wire on top of 2 ft sheepwire and there’s the same power at the fencer unit as the far end
 

Ukjay

Member
Location
Wales!
It is not as expensive in the realms of knowing the job is done right if you buy 500m drum, rather than having to dig it up later to rectify faults - I assume you can also claim the vat back too

 

Poorbuthappy

Member
Livestock Farmer
Location
Devon
I too always understood flex cable was not up to the job.
However, I would like to know why all the short cables on battery fencers are only copper flex? Or is it a particular spec? Guessing not as it never seems to last that long before breaking up. Usually only a very small wire too.
 

Bury the Trash

Member
Mixed Farmer
For fencing fields where sheep are would people recommend 2.5mm HT wire or 3.15mm HT wire? I have been using 3.15mm until now but wonder if 2.5mm would be better. Mainly used for top wiring by drystone walls and also above HT8-80-22 netting.
2.5. Is way cheaper and easier to put up.

3 takes fair bitmore straining and really for no extra gain .

I often wonder whether that green wire is actually easier for them to see, grey blends right in. That's wherewhite poly in a non or semiperm situation has an advantage ime, the sight of the fence as an aid to the phsycological side of it that is.......:unsure:
 

dt995

Member
Location
Carmarthenshire
Any good ideas to raise the visibility of steel wire? I've seen people talk about hanging plastic bags on, but I feel they might come off and get eaten, same with tinfoil (although being conductive would be better than bags while on the line).
 

Dry Rot

Member
Livestock Farmer
Any good ideas to raise the visibility of steel wire? I've seen people talk about hanging plastic bags on, but I feel they might come off and get eaten, same with tinfoil (although being conductive would be better than bags while on the line).

I cable tie white tape to it. I've found it is best to invest in the better tape up here which lasts quite well.
 
Don’t bother with the twin and earth cable it’s only good for less than 1000 volts and the joints where you connect to the fence lines will corrode in time Better bite the bullet and use proper lead out cable and bolt every joint too not wrap around. Have 2 miles of 2 strand of ht wire on top of 2 ft sheepwire and there’s the same power at the fencer unit as the far end
Have been thinking of fencing like that for some time. The wire netting I've seen is softer and thiner. My thoughts were it will stretch it sheep rub on it. What is your experience please
 

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