Horse Barn, Equipotential Grounding

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jmellc

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Location
Durham, NC
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Facility Maintenance Tech. Licensed Electrician
I have made mention of similar issues before but have come up with no real answers.

We are quoting a job on a horse barn. Has 2 concrete slabs on each side entrance with dirt floors between 4 stalls. I have no idea if the concrete has grid wire or rebar in it. I hope I don't have to break up the concrete to find out. Would it work to drill through slabs to ground and drive a rod at each? Or maybe drill sideways with a 3 foot bit and insert rebar for a longer contact surface? Or core drill a 4 inch hole, drive rebar to ground below and fill in with fresh concrete patch?

What has anyone done lately? I am also contacting head of inspections for that county for his opinion.
 
jmellc said:
I have made mention of similar issues before but have come up with no real answers.

We are quoting a job on a horse barn. Has 2 concrete slabs on each side entrance with dirt floors between 4 stalls. I have no idea if the concrete has grid wire or rebar in it. I hope I don't have to break up the concrete to find out. Would it work to drill through slabs to ground and drive a rod at each? Or maybe drill sideways with a 3 foot bit and insert rebar for a longer contact surface? Or core drill a 4 inch hole, drive rebar to ground below and fill in with fresh concrete patch?

What has anyone done lately? I am also contacting head of inspections for that county for his opinion.
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I've done a lot of equipotential bonding with all the dairy work our shop does. You'll need to read the code sections in 547 and determine if it applies to your situation. As well as get your inspector on board with anything you plan on doing before you start. Some inspectors make a big deal out of it, others are more lax, this code is very open to interpretation in my opinion.

To put things in perspective, on the dairy we're doing now, every piece of concrete the cows can stand on has mesh we've bonded. The only electrical in the barn is the panel and other electrical enclosures taking up 8' of wall space in one area, as well as lights in the ceiling. But yet, we still have to have the concrete crew install mesh for an equipotential plane the entire length of a 2200' long barn.
 
ActionDave said:
There are a lot of 'hobby horse' barns in my area, twenty five acres or less, three or four stalls, a few lights and convenience recpts, tack room wired for a computer, lights and a desk. In my opinion these type of places do not require equi potential bonding.
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Strict reading of 547 probably requires it if it is a place frequently occupied by an animal of about any kind, maybe even the rats in an outbuilding;)

But I agree, that many times it isn't or hasn't been done and there has been little problems. The places that seem to have the most issues is dairy farms. If they have low level stray voltage problems but the owner/operators aren't directly noticing it, it may first show up as loss in milk production. But in those kinds of places you have a lot more items that are associated with electrical operated equipment that is also more directly associated with the animals. Many other animals only come in contact with water tank heaters for potential electrical hazards and not much more then that. If the water tank is in an area that doesn't freeze they may not have much risk at all.
 
We make a voltage ramp so to speak. rods or rebar driven at a 45 degree angle starting at the doorway. the rods are 1 foot apart across the whole doorway. Down and away from building.
 
jmellc said:
I have made mention of similar issues before but have come up with no real answers.

We are quoting a job on a horse barn. Has 2 concrete slabs on each side entrance with dirt floors between 4 stalls. I have no idea if the concrete has grid wire or rebar in it. I hope I don't have to break up the concrete to find out. Would it work to drill through slabs to ground and drive a rod at each? Or maybe drill sideways with a 3 foot bit and insert rebar for a longer contact surface? Or core drill a 4 inch hole, drive rebar to ground below and fill in with fresh concrete patch?

What has anyone done lately? I am also contacting head of inspections for that county for his opinion.
Click to expand...

Knowing the reasoning and why it works will help you here. By simply driving vertical rods, you don't create a voltage "ramp", the potential differences in the ground around such an electrode can change quite a bit in a short distance. With an animal with a long base between potential points of contact you need to make those potential differences occur over a longer distance so it has less effect on the animal. An angled rod that gets deeper as you leave the area will leave less voltage potential between the animal's feet as they enter or approach the electrode then it will for same electrode in a vertical position.
 
I recently designed an equipotential bonding ground plan for a new race horse stables and yard. The contractor bitched at me about the cost until I asked how much is a race horse is worth?

Ufer and perimeter earthing systems are alien to most UK electricians. They’d better get used to it, they’re in the next thrilling episode of BS7671
 
interesting problem OP lists. a concrete slab that may not be conducive to becoming a ufer......, sounds like you need to invent a electrically conductive solution that you can soak the concrete with, thus allowing the concrete to become a ufer :thumbsup:
 
kwired said:
Knowing the reasoning and why it works will help you here. By simply driving vertical rods, you don't create a voltage "ramp", the potential differences in the ground around such an electrode can change quite a bit in a short distance. With an animal with a long base between potential points of contact you need to make those potential differences occur over a longer distance so it has less effect on the animal. An angled rod that gets deeper as you leave the area will leave less voltage potential between the animal's feet as they enter or approach the electrode then it will for same electrode in a vertical position.
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From personal experience it does matter. I had a "ramp" on the entry to a Dairy, however we neglected the exit.:ashamed: All the cows would jump out. Angled rods worked.
 
You can do what is sometimes done for pool decks that don't have the required bonding. Saw cut the surface and install #6 solid copper in the saw cuts. Cover the top with sealant and connect the #6 to the electrical grounding system in the area.
 
don_resqcapt19 said:
You can do what is sometimes done for pool decks that don't have the required bonding. Saw cut the surface and install #6 solid copper in the saw cuts. Cover the top with sealant and connect the #6 to the electrical grounding system in the area.
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high traffic animal surface though. tripping hazard over time? perhaps the cut has to be 2-3x deeper than dia of wire, then cuts filled with epoxy. sounds expensive.
 
FionaZuppa said:
interesting problem OP lists. a concrete slab that may not be conducive to becoming a ufer......, sounds like you need to invent a electrically conductive solution that you can soak the concrete with, thus allowing the concrete to become a ufer :thumbsup:
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In an animal confinement building mother nature has already done that for us - to name it in a way that can be mentioned here lets just call it animal waste.:happyyes: Raises the conductivity of everything in the area pretty well.
 
ActionDave said:
There are a lot of 'hobby horse' barns in my area, twenty five acres or less, three or four stalls, a few lights and convenience recpts, tack room wired for a computer, lights and a desk. In my opinion these type of places do not require equi potential bonding.
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But have you considered what some horses are worth & what if they put some other animals in there?:jawdrop:
I try to cover myself with people's animals.
 
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