Grounding a metal barn sub panel

I am running power to my barn from the house main panel. It is a 300 ft run using 6 awg wire. The wire will be in 1 1/4" conduit.I intend to put a 20 amp 120 volt sub panel there. I buried a 8 ft ground rod. The guy who built my house tells me the code says to not connect a ground at the main panel. He says the only ground should be to the buried ground rod. I’m concerned because I inspected a house once where a horse was electrocuted touching the metal barn. I appreciate any advice. I got rid of all my code books when I retired.

I would first suggest that you wire it for 240V, even if you feel it won’t be necessary.

By today’s standards, you are required to run both a neutral (grounded) conductor and a grounding conductor. For a 240V feed, this would be a four-wire run. If you decide to go with a 120V system, you still need three conductors.

The ground-rod is required at separate structures, so your EGC will be bonded to the sub panel and to the ground-rod. The neutrals should remain isolated at the sub panel, but bonded to the service panel.

The information that you’re receiving is incorrect.

What do you mean by a buried rod? Rods are required to be installed down into the earth.

The guy who said not to connect the feeder EGC to the main panel is wrong, it’s required to do so.

IMO you should consult a qualified electrician to help you ensure that everything is done correctly. Aren’t there permits and inspections required?

I didn’t word my question very well. When I say a buried rod I mean I have driven an 8’ ground rod about 2" below the earths surface.

I’m told the new code that the city of Prescott Valley recently adopted requires the barn ground be completley seperate from the ground buss at my main panel.

In other words I need to pull just 3 conductors through the conduit and then ground the sub panel to the earthen ground at the barn. No ground connection at the main panel.

I don’t have access to the latest code and wondered if anyone else was aware of this.

The NEC stopped allowing 3 wire feeders to subpanels in outbuilding a while ago.

The grounding conductor will connect to the ground buss in your service panel as well as the isolated ground bus in the remote panel. The remote will also connect to the ground rod.

This information sounds incorrect and is not consistent with the NEC.

If you only have a single 20 amp circuit the NEC does not require that you install a ground rod or any other grounding electrode.

Although Robert and my information may sound contradictory, the answer depends on whether you have a single circuit or a feeder with a subpanel. The rules change. A better description of the circuit size and usage would narrow the answer down.

May I suggest:

  1. A second ground rod. (may be code)
  2. Bonding the metal barn to the GEC or ground bar in the subpanel.
  3. GFCI protection for any circuit in the barn. (not a GFCI breaker in the house main panel as this would tend to nuisance trip.)

Horses have four feet in contact with the earth. And they don’t wear rubber soled shoes. They may even wear metal ones. For these reasons, and others, a horse can be killed by stray current that an adult person may not even feel.

Some of this may be above the code, but I think all of it is prudent.

I agree, more information is needed to properly answer these questions. I would start with why would you install a subpanel for one 120 volt, 20 amp circuit?

Does anyone see the possibility that 547.10 may also be applicable?

Originally I was going to run 220 volt. After pricing copper wire and figuring the size I would need for about 50 amps at that distance (300 ft) I realized I really only needed a lighting circuit and an outlet or two. I decided to run 6 awg wire and be content with a 20 amp service.

Based on what you have posted (and I commend Robert and Jim for trying to decipher your intent) I appears that even if you are only intending to run a 120V line to this building…you are installing (in your own words) a sub-panel. This leads me to believe you are intending it to be a Feeder…with that said you will need to be aware of exactly what Jim and Robert are telling you. While they are both speaking of different situations (eg: feeder versus branch circuit) they are both correct…

If you were simply running a branch circuit to the barn and the last overcurrent device was in your dwelling…and the device at the barn was simply a disconnection means then you would not need a GES at the barn. If indeed you are intending to establish an electrical distribution system in the barn with additional circuits (branch circuits) in the barn and protection of those circuits in the barn…then you do not have a branch circuit feeding the building…you have a feeder.

Beyond that…I believe Jim and Robert are clear. You have to decide which circuit you have.

Maybe…If the location meets the scope of 547.1(A) or (B) and if the space meets the design of 547.10(A)(1) or (A)(2).

The question always comes up…are horses considered “livestock” and I think this answers that.

"Yes, horses are livestock. Traditionally, and legally, horses have been considered livestock in the United States. Even today, horses are still kept and raised on a farm or ranch and are used in a commercial enterprise. The United States horse industry is a major business that makes a significant contribution to the economic well-being of the entire country. The U. S. horse industry has a $112.1 billion impact on the U. S. economy; generates 1,404,400 full-time equivalent jobs; and pays $1.9 billion in taxes to all levels of government. " Source - http://www.thehorse.com/articles/10520/definition-of-horses-as-livestock