Ground Wire to seperate building

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scott657

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I 'm pretty sure I am right about this , but I need some positive reinforcement.

We have a service on a pole, the service is grounded and the neutral is bonded.
The service serves to small buildings. the feeders running to these buildings are in PVC underground No ground wire was pulled from the service to these buildings. They are sub panels from the service. The panels themselves are grounded via #6 and a driven rod. A ground wire should have been pulled and sized as an equipment ground. Am I correct?
 
Depends on which code cycle was being referenced when the install was made. If the install was made before the '08 NEC, then the installation as described does not require an EGC as long as there are no other metallic paths between the service and either building.

At that point, the panels in each building would be grounded as though they were services, bonding the GEC/MBJ/EGC/grounded conductor all together.
 
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250.32 Two or More Buildings or Structures Supplied from a Common Service.
(A) Grounding Electrode. Where two or more buildings or structures are supplied from a common ac service by a feeder(s) or branch circuit(s), the grounding electrode(s) required in Part III of this article at each building or structure shall be connected in the manner specified in 250.32(B) or (C). Where there are no existing grounding electrodes, the grounding electrode(s) required in Part III of this article shall be installed.
If a single service supplies more than one building, such as illustrated in Exhibit 250.16, and the feeder is installed with an equipment grounding conductor, 250.32(A) requires that a grounding electrode system be established, unless one already exists. The equipment grounding bus must be bonded to the grounding electrode system. The disconnecting means, building steel, and interior metal water piping must be bonded to the grounding electrode system. All non-current-carrying metal parts of electrical equipment are required to be grounded by connection to the equipment grounding bus.
 
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In 05 you we're allowed to do it either way. A three wire or a 4 wire.
Some direct burial wire always had a 4th wire.
Single phase 240 v.
 
scott657 said:
This diagram was what I was going by. It was from my 05 hand book from
Click to expand...

You have to read pass that illustration, 250.32(B)(2) would be your application.

Roger
 
250.32 Two or More Buildings or Structures Supplied from a Common Service.
(B) (2) Grounded Conductor.
Where (1) an equipment grounding conductor is not run with the supply to the building or structure, (2) there are no continuous metallic paths bonded to the grounding system in both buildings or structures involved, and (3) ground-fault protection of equipment has not been installed on the common ac service, the grounded circuit conductor run with the supply to the building or structure shall be connected to the building or structure disconnecting means and to the grounding electrode(s) and shall be used for grounding or bonding of equipment, structures, or frames required to be grounded or bonded. The size of the grounded conductor shall not be smaller than the larger of
(1) That required by 220.22
(2) That required by 250.122


Similar to the provisions of 250.30(A)(2), 250.32(B)(2) also eliminates the creation of parallel paths for normal neutral current on grounding conductors, metal raceways, metal piping, and other metal structures. In previous editions of the Code, the grounding electrode conductor and equipment grounding conductors were permitted to be connected to the grounded conductor at a separate building or structure. This multiple-location grounding arrangement could provide parallel paths for neutral current along the electrical system and along other continuous metallic piping and mechanical systems as well. Connection of the grounded conductor to a grounding electrode system at a separate building or structure is permitted only if these parallel paths are not created and if there is no common ground-fault protection of equipment provided at the service where the feeder or branch circuit originates.
 
wireways said:
Connection of the grounded conductor to a grounding electrode system at a separate building or structure is permitted only if these parallel paths are not created and if there is no common ground-fault protection of equipment provided at the service where the feeder or branch circuit originates.
Click to expand...

Do you find it odd that the NEC is concerned about parallel paths on the load side of the service but requires them on the line side?
 
iwire said:
Do you find it odd that the NEC is concerned about parallel paths on the load side of the service but requires them on the line side?
Click to expand...
Bob,
You know that the electrons don't behave the same way on the line side of the service:D
 
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