wayne123
Senior Member
- Location
- North Carolina
If I have an equipment grounding conductor run with a 240v w/ a neutral circuit and there are no grounding electrodes to ground in the barn do I need to drive a ground rod?
Barn
- Thread starter wayne123
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mvannevel
Senior Member
- Location
- Hesperia, Michigan
Re: Barn
Yes, 250.32(A).
Yes, 250.32(A).
- Location
- Logan, Utah
Re: Barn
If the circuit is a multiwire branch circuit than you can use the exception to 250.32(A). A multiwire branch circuit is treated as a single branch circuit, see Article 100 definitions.
Chris.
If the circuit is a multiwire branch circuit than you can use the exception to 250.32(A). A multiwire branch circuit is treated as a single branch circuit, see Article 100 definitions.
Chris.
wayne123
Senior Member
- Location
- North Carolina
Re: Barn
Its just a storage barn of sorts, no animals involved.The N and egc are not to be bonded together for this is it? I consider this as a sub panel from the main house. The ground rod goes to the ground and the N is isolated, correct?
Its just a storage barn of sorts, no animals involved.The N and egc are not to be bonded together for this is it? I consider this as a sub panel from the main house. The ground rod goes to the ground and the N is isolated, correct?
Re: Barn
If you ran a grounding conductor from the house to the barn, then the grounds and neutrals must be kept separated, otherwise you will have neutral current on your grounding conductors. If the barn is to be used for livestock, then the grounding conductor must be insulated or covered copper. If you have more than one branch circuit in the barn then you must install a grounding electrode. See 250.32 and 547.9 in the NEC.
If you ran a grounding conductor from the house to the barn, then the grounds and neutrals must be kept separated, otherwise you will have neutral current on your grounding conductors. If the barn is to be used for livestock, then the grounding conductor must be insulated or covered copper. If you have more than one branch circuit in the barn then you must install a grounding electrode. See 250.32 and 547.9 in the NEC.
mvannevel
Senior Member
- Location
- Hesperia, Michigan
Re: Barn
If you've run an EGC along with your feeder (and I'm assuming this is a feeder so the exception to 250.32(A) can't be used and you'll need a grounding electrode system) to the storage "barn", you keep it separate from the grounded conductor in the panel at the "barn. Bond to your grounding electrode system from the equipment grounding bar in that panel. Even if this is just a storage building, if this is an agricultural structure fed from a distribution point, there are some specific requirements for the sizing and connection of the EGC in 547.9.
[ August 12, 2005, 09:01 AM: Message edited by: mvannevel ]
If you've run an EGC along with your feeder (and I'm assuming this is a feeder so the exception to 250.32(A) can't be used and you'll need a grounding electrode system) to the storage "barn", you keep it separate from the grounded conductor in the panel at the "barn. Bond to your grounding electrode system from the equipment grounding bar in that panel. Even if this is just a storage building, if this is an agricultural structure fed from a distribution point, there are some specific requirements for the sizing and connection of the EGC in 547.9.
[ August 12, 2005, 09:01 AM: Message edited by: mvannevel ]
- Location
- Massachusetts
Re: Barn
I suggest you get a newer code book than 1999 as 547-8(c) is entirely different now.
250.32(B)(2) directly allows using the grounded conductor as the grounding means.
Please explain how using the grounded conductor as a grounding means would overload the grounded conductor?
I suggest you get a newer code book than 1999 as 547-8(c) is entirely different now.
250.32(B)(2) directly allows using the grounded conductor as the grounding means.
- Location
- Massachusetts
Re: Barn
Bump
Bump
peter d
Senior Member
- Location
- New England
Re: Barn
Sam, you'll just have to be left out of the loop. I happen to know why they bumped it, but that's for me to know and you to find out.
Sam, you'll just have to be left out of the loop. I happen to know why they bumped it, but that's for me to know and you to find out.
- Location
- Massachusetts
Re: Barn
Originally posted by physis:
Just when I thought I understood you two guys.
Bump?
Bump, as in I bump you to the front of the line.
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
Re: Barn
Sam, don't talk to those strange fellows bumping each other. They're not to be trusted.
BTW, I PM'ed a fella, some grind should accompany the bump in short order.
Sam, don't talk to those strange fellows bumping each other. They're not to be trusted.
BTW, I PM'ed a fella, some grind should accompany the bump in short order.
james wuebker
Senior Member
- Location
- Iowa
Re: Barn
wayne123
You wrote (Its just a storage barn of sorts, no animals involved.The N and egc are not to be bonded together for this is it? I consider this as a sub panel from the main house. The ground rod goes to the ground and the N is isolated, correct?)
This is correct wayne123
Bye now,
Jim
wayne123
You wrote (Its just a storage barn of sorts, no animals involved.The N and egc are not to be bonded together for this is it? I consider this as a sub panel from the main house. The ground rod goes to the ground and the N is isolated, correct?)
This is correct wayne123
Bye now,
Jim
wayne123
Senior Member
- Location
- North Carolina
Re: Barn
Thanks Jim.
Thanks Jim.
Re: Barn
When attempting to use a neutral to carry normal generated unbalanced loads AND your fault currents, you generate more heat. Now consider the length of the run and estimated continual load and either upsize your neutral when using this method or just go ahead a run a grounding conductor with your feed. If you decide neither it is a good suggestion of mine to drive a ground rod at Barn and establish a grounding system there.
When attempting to use a neutral to carry normal generated unbalanced loads AND your fault currents, you generate more heat. Now consider the length of the run and estimated continual load and either upsize your neutral when using this method or just go ahead a run a grounding conductor with your feed. If you decide neither it is a good suggestion of mine to drive a ground rod at Barn and establish a grounding system there.
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
Re: Barn
Consider a service: We are allowed to have a smaller neutral than ungrounded conductors. URD is designed that way. The neutral only has to be sized large enough for the unbalanced current that could flow on it.
When dealing with a service, we're dealing with virtually unprotected conductors. It is an industry standard that the neutral of URD is smaller than the ungrounded conductors.
The reason that a 6/3 NM cable has a #10 grounding conductor is because 250.122 calls for that size EGC. Why is a #10 acceptable for carrying fault current for a 50 amp circuit fed with #6? We're talking about a tremendous amount of energy moving here, a lot of heat.
Because faulting is short-lived by nature. The NFPA took that into account when they created 250.122.
...For the duration of the fault, which will be very short. It is absolutely no different than a regular short circuit. Would you consider the neutral to be undersized if it were the same size as the ungrounded conductor? The ungrounded conductor is an acceptable size for a fault.
Consider a service: We are allowed to have a smaller neutral than ungrounded conductors. URD is designed that way. The neutral only has to be sized large enough for the unbalanced current that could flow on it.
When dealing with a service, we're dealing with virtually unprotected conductors. It is an industry standard that the neutral of URD is smaller than the ungrounded conductors.
The reason that a 6/3 NM cable has a #10 grounding conductor is because 250.122 calls for that size EGC. Why is a #10 acceptable for carrying fault current for a 50 amp circuit fed with #6? We're talking about a tremendous amount of energy moving here, a lot of heat.
Because faulting is short-lived by nature. The NFPA took that into account when they created 250.122.
It's a good suggestion, but you can't take credit for it.
Re: Barn
Let us assume that this topic is about mounting an enclosure in the barn for service in this area.
Is the Barn a metal structure or wooden? Lets assume it is metal. My earlier comment on sizing the neutral was based on sizing the neutral to that of the largest ungrounded conductor feeding the barn. Now all the conductor need be the same in rating. With that being said, lets focus on the service there. Mount your service disconnect or panel and attache the neutral to the terminal bus determined to be your grounding bus. Then run a grounding electrode conductor to your new grounding electrode(ground rod). Install your main bonding jumper, which should be bonded to the service disconnect or panel, and the ground bus. This ground bus shall be where your neutrals and grounding conductors terminate. Because you have pulled a Neutral that is the same size as your largest ungrounded conductor you will be within the code specified in the other postings.
[ August 17, 2005, 03:58 PM: Message edited by: OneWay ]
Let us assume that this topic is about mounting an enclosure in the barn for service in this area.
Is the Barn a metal structure or wooden? Lets assume it is metal. My earlier comment on sizing the neutral was based on sizing the neutral to that of the largest ungrounded conductor feeding the barn. Now all the conductor need be the same in rating. With that being said, lets focus on the service there. Mount your service disconnect or panel and attache the neutral to the terminal bus determined to be your grounding bus. Then run a grounding electrode conductor to your new grounding electrode(ground rod). Install your main bonding jumper, which should be bonded to the service disconnect or panel, and the ground bus. This ground bus shall be where your neutrals and grounding conductors terminate. Because you have pulled a Neutral that is the same size as your largest ungrounded conductor you will be within the code specified in the other postings.
[ August 17, 2005, 03:58 PM: Message edited by: OneWay ]
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