Ufer grounding an electric fence

2462 Views 11 Replies 6 Participants Last post by gregzoll, Mar 6, 2016

jaybee3

Discussion Starter · Mar 5, 2016

Hello ~

I am putting in an electric fence. I have what I think is a simple question about grounding, and about Ufer grounding specifically.

I have located the conductor to the buried/enclosed electrode in my garage wall behind the main source box, but the conductor is pretty well insulated and I would like to avoid cutting that all open if I can help it. Next to the conductor, however, is a piece of rebar that was "stubbed up" and sticks a couple of inches out of the foundation. In an Ufer grounding system, is all of rebar enclosed in the concrete foundation considered to be ground? Can I just clamp the fence's ground wire to the rebar instead to the actual electrode conductor?

For kicks, is it a code violation for me to clamp on to the conductor?

Save

1 - 12 of 12 Posts

gregzoll

· #2 · Mar 5, 2016

Yes all rebar in the slab is tied together as a complete bond. The ground point is supposed to be open for inspection and also if needing to fix.

You can get the ground blocks that use a Split clamp to attach to the ground wire from the panel or meter. They come with a PVC protective cap and back.

I had to clamp my Satellite & DSL line to the ground wire for my meter with a Split bolt, since I could not get deep enough below the main ground bolt. It is still compliant, since I used a bolt made for two wires.

Save

ArcLazer

· #3 · Mar 5, 2016

250.52 (A)(3) states that if multiple concrete-encased electrodes are present at a building or structure, it shall be permissible to bond only one into the grounding electrode system.

It doesn't say you can't use more than one location. Does that help?

Save

AllanJ

· #4 · Mar 5, 2016 (Edited)

It is permissible and actually better to ground a new item (such as a separately run equipment grounding conductor) by clamping to to a ground wire (grounding electrode conductor) running from the panel to a ground rod or protruding rebar as opposed to clamping to the ground rod or protruding rebar itself.

Save

Reactions: 1

jaybee3

Discussion Starter · #5 · Mar 5, 2016

Awesome, thank you all and I love this site, glad I finally took a minute to sign up.

I figured worst case scenario, I try the easiest possible grounding solution and test the voltage right at the fence charger before I spin any wheels setting up an ungrounded fence. But now I can proceed with more confidence.

For what it's worth, my whole neighborhood was built in 2001 or thereabouts, and I suspect all of the houses around here have the ground access blocked off. The main meters are typically off the garage, but all of the wiring for the meter is harnessed between the house frame and the garage drywall, and there's a swarm of insulated wired running across the attic down into that one spot. It looks nice because everything's out of sight, but now I'll be patching up and netting off a section of my drywall. Oh, the pains of doing it all yourself!

Save

Reactions: 1

Oso954

· #6 · Mar 5, 2016

Why are you connecting the electric fence to the house Ufer ?

Typically you set the ground rods near the fence about 10 ft apart. If the ground point is too far away, you can render the fence ineffective.

Conversely, having electric fence pulses on your house ground can raise heck with electronics.

Save

Reactions: 1

DanS26

· #7 · Mar 5, 2016

Oso954 said:
Why are you connecting the electric fence to the house Ufer ?

Typically you set the ground rods near the fence about 10 ft apart. If the ground point is too far away, you can render the fence ineffective.

Conversely, having electric fence pulses on your house ground can raise heck with electronics.

Totally agree....why are you connecting an electric fence ground to the residence ground. Big mistake especially if you are using the high powered Australian fence chargers.

Treat the fence charger system as a completely separate electrical system. That independent system will use the earth as a return path without involving the residence ground.

Save

jaybee3

Discussion Starter · #8 · Mar 6, 2016 (Edited)

Oso954 said:
Why are you connecting the electric fence to the house Ufer ?

Typically you set the ground rods near the fence about 10 ft apart. If the ground point is too far away, you can render the fence ineffective.

Conversely, having electric fence pulses on your house ground can raise heck with electronics.

Thanks for replying! I was waiting for this, and I agree with you in essence. So do you mean that simply the pulses could raise heck, or that a true surge on the fence could? If it's just the fact that the fence is plugged in, then I'm definitely listening. If ground is ground, I just don't understand (meaning that I am ignorant) how grounding my AC-powered charger would necessarily or automatically affect my home electronics, unless there is a lightning strike. In that vein, I also didn't understand why people could connect their cable, satellites and antennae to their Ufer grounds but not a fence charger. My fence charger is a low-impedance, .07 joule output with a 2-mile range. I don't know what an "Australian" charger is.

My view up to this point is that ground rods are not practical and using the Ufer ground is a risk -- or at least a lesser of two evils -- that I'm willing to take. I'm in a very arid climate with some serious hardpan within about 12" of the surface, which makes ground rods a legitimate hassle and potentially ineffective. We also get almost no inclement weather beyond some gusty winds and intermittent winter snow, so lightning is very low on my list of concerns. Very high on my list of concerns, however, is my family, pets, neighbors and other passersby around my small suburban lot. The specifications are that the ground rods ought to be a minimum of 50' away from any existing grounding electrode, which simply isn't possible in my case. So I can either use ground rods and risk turning my property and my neighbors' into an electric field between an array of closely-placed grounds, or I can use the Ufer ground and risk some damage to my home electronics. Again, I haven't taken the latter risk very seriously because I'm under the impression that (1) lightning is the only real threat and (2) the moisture of the foundation's concrete and all of the rebar would sufficiently absorb the charge.

Could I just do what a buddy of mine did and not even bother grounding the fence at all? His charger is solid state.

What's funny is that we all know that after all this fuss, the dogs will get one or two shocks and then I'll never plug the stupid thing in again.

See less See more

Save

Oso954

· #9 · Mar 6, 2016

As Dan stated, you are setting up a earth return system.

The hot wires on the fence are energized at hi voltage. The current flows from the fence, down the animal to earth, and travels to the ground rods. (Neutral pickup rods would also be an accurate name) once the neutral current hits the ground rod, it transfers to the return line and returns to the charger.

The manual is telling you to keep your ground rods at least 50 feet away from an
Existing Equipment grounding system. Elsewhere in the manual, it should say never connect the fence ground to an equipment grounding system.
Yet, when you say connect to your Ufer, you are proposing to make a direct connection to an existing equipment grounding system.

If you do connect it to the Ufer it could damage electronics. But even without damage, it could wipe data on your computer, it can make your phone skreech, it might scramble your tv picture, every time a shock is delivered.

I sure hope the system you are talking about is a pet level system, not a farm animal system. But with a 2 mile range it sounds like farm animal size. That would be cruel and unusual treatment of your pets.

An even better choice would be a wireless fence, or an electronic fence. It is a signal wire that is buried a few inches deep around the area that you wish to contain the pet in. The pet wears a collar unit. When it approaches the wire, a tone sounds. If he crosses the boundary, there is a shock delivered. They learn quickly to back away from the boundary on hearing the tone. After they have learned to respect he boundary, you can go back to a standard collar.

See less See more

Save

Reactions: 1

gregzoll

· #10 · Mar 6, 2016

jaybee3, there is a reason why electric fence systems are not attached to a barn ground, or building ground. It as what has already been state. The majority of the systems are Solar powered, since they are going to be away from any main electrical, along with they now use a tape vs. wire.

The manual will state proper method for connecting or running mains power to the equipment if not battery or solar powered. The worse thing that you want to happen with a electric fence system, is to have it get hit by a lightning surge and then have the surge back feed to the panel and fry equipment. That is the biggest cause of why dairy barns end up with the newer computerized milking equipment fried when someone has not properly hooked up an electric shock system.

Save

jaybee3

Discussion Starter · #11 · Mar 6, 2016

Okay, I'm convinced. I'll figure out a non-Ufer solution to this, like an obscure corner of the property where I can use irrigation to keep the ground moist.

As for my poor pets, the charger is specifically for small animals, the amperage is low and the current pulses. People with shoes are also protected, based on the reviews. This is the only way to keep dogs (and rabbits) out of the garden and away from trees (the dogs literally are eating the trunks and roots). There is a ton of dirt and sand where they are free to dig and bury their bones, and they have plenty to chew on, so I just need this one deterrent.

Thanks again, everyone. I'll check back in a day or so to see if anyone else has any additional insights. Even if I suck at doing it myself, I do love the learning process.

Save

Reactions: 1

gregzoll

· #12 · Mar 6, 2016

You do not need to keep the ground moist. It would actually cause thr unit to drain more to Earth, then it should.

You want the unit where you can get to it easy, so that you do not have to go take a hike to check on it.

Even on dry ground, you can still get shocked.

Save

1 - 12 of 12 Posts

This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.

Top Contributors this Month