Equipotential Plane for Livestock

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Little Bill

Little Bill

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Tennessee NEC:2017
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Semi-Retired Electrician
I have a customer that is adding on to his barn. He is adding a wash down pad for his show cattle. It will be a concrete pad with washing equipment. I don't think any of the equipment requires power other than maybe an igniter for a gas tankless water heater. But there will be two fans mounted there to aid in drying them. I was wondering if an equipotential plane would be required in and around this concrete pad?
 
I believe I would really do some studying and research on this.
Cattle can be very sensitive to stray voltage.
 
ptonsparky said:
It’s not so much the power you are using but whats around you. Kwire gave an excellent run down on pool bonding in another thread. Treat it the same way.

Don’t forget the gradient ramps.
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I'm very familiar with pool bonding as I have done lots of pools. However, I've never dealt with a live stock equipotential plane. Not sure if tying rebar together, making grids, under or in the concrete would suffice or if a wire mesh would need to be installed before the pour. Also don't know how far away from the pad I would need to extend the grid or mesh.
 
Little Bill said:
I'm very familiar with pool bonding as I have done lots of pools. However, I've never dealt with a live stock equipotential plane. Not sure if tying rebar together, making grids, under or in the concrete would suffice or if a wire mesh would need to be installed before the pour. Also don't know how far away from the pad I would need to extend the grid or mesh.
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The important thing is to make it "taper off" when leaving the slab. Make it get deeper as you move away from slab so there won't be a sudden point with a large voltage change when the cow takes that next step, which is what would happen at an abrupt end to the equipotential plane or if you tapered off too steep.

Remember a cow can span across a bigger distance between a front hoof and a rear hoof than a human can and is why they are more sensitive to voltage gradient in the surface, plus they typically don't wear anything with any insulating qualities on their feet like humans often do.
 
Little Bill said:
I'm very familiar with pool bonding as I have done lots of pools. However, I've never dealt with a live stock equipotential plane. Not sure if tying rebar together, making grids, under or in the concrete would suffice or if a wire mesh would need to be installed before the pour. Also don't know how far away from the pad I would need to extend the grid or mesh.
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It’s been awhile for me. Mesh or rebar. The gradients have spacing farther apart at the approach, then reduce as they get closer to the pad. Both entry and exit.
 
Hv&Lv said:
I believe I would really do some studying and research on this.
Cattle can be very sensitive to stray voltage.
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Maybe not so sensitive.
My father was a farmer, Sometimes we had a few cattle in a temporary field with an electric fence. It didn't bother them other than a slight twitch. Of course they have cloven hooves. Unlike my poor collie who got his wet feet on the electric fence..............:(
 
Besoeker3 said:
Maybe not so sensitive.
My father was a farmer, Sometimes we had a few cattle in a temporary field with an electric fence. It didn't bother them other than a slight twitch. Of course they have cloven hooves. Unlike my poor collie who got his wet feet on the electric fence..............:(
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Cattle are very sensitive. I've heard they won't drink if they sense voltage/current. Even effects their milking.
Electric fence is different than stray voltage they may be standing on.
 
Little Bill said:
Cattle are very sensitive. I've heard they won't drink if they sense voltage/current. Even effects their milking.
Electric fence is different than stray voltage they may be standing on.
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Well, it's just what I found found with them in real life. There were about half a dozen milking cows, about 30 heifers, and a field full of stirks.
My engineering degree left that behind.
 
Besoeker3 said:
Well, it's just what I found found with them in real life. There were about half a dozen milking cows, about 30 heifers, and a field full of stirks.
My engineering degree left that behind.
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There is my new word for the day although I doubt I'll ever be able to use it
 
Understood... looked it up as it was new to me... no doubt I'll use it in watercooler conversations often :p :p
 
augie47 said:
Understood... looked it up as it was new to me... no doubt I'll use it in watercooler conversations often :p :p
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Ah, OK. A little digression on more livestock. Besides the bovine species we had about 3,000 sheep. March/April was lambing season. I help with the lambing shepherd.
Excuse the digression.
 
Cattle generally just stay away from an electric fence once they learn what happens if you get too close.

A water tank or other object that has a voltage gradient surrounding it, they start to sense that voltage as they approach, don't like that and generally will just stay away. If you are trying to herd them into an area where they must cross such a voltage gradient they will put up some fight or will run when finally crossing that gradient.
A good cattleman will know they are disturbed by something by the way they are acting.

Say it is a faulted water tank heater - there may be voltage gradient in the surface as you approach - cattle feel this and just stay away. Pigs however are more curious about things, they will likely come all the way to the water tank and be electrocuted when they touch it. Then the next one will be curious and approach and get electrocuted as well.

Same with electric fence - cattle learn to just stay away, pigs have to come back and test it every so often just because of curiosity.
 
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