Grounding of sub Panel

[taylord40]

I need a clarification on Article 250.32. I have a 100 amp 1 phase sub panel ran to a detached building 225' away from the house. No water line or gas line ran to the new building. I ran 3 lines to the building, drove two ground rods and treated the sub panel as a new service. The Article say you should run a Equipment ground. with the feed conductors, but under the exceptions is says the 4 wire is not needed if these conditions are met, which they all are. Please give me your input. If there was an issue where a fault would occur at the detached building I would not want it going back to the house, but going to the driven grounding rods.

Thanks,

 

[KaBoom!]

Which conditions did you meet?
What makes this a new service?

It is my understanding that you would need to run 4 wires if doing this new, but I am interesting in hearing your reasoning.

 

[roger]

I need a clarification on Article 250.32. I have a 100 amp 1 phase sub panel ran to a detached building 225' away from the house. No water line or gas line ran to the new building. I ran 3 lines to the building, drove two ground rods and treated the sub panel as a new service. The Article say you should run a Equipment ground. with the feed conductors, but under the exceptions is says the 4 wire is not needed if these conditions are met, which they all are. Please give me your input. If there was an issue where a fault would occur at the detached building I would not want it going back to the house, but going to the driven grounding rods.

Thanks,

What year code book are you using and what year code is your area under?

Roger

 

[electrofelon]

. If there was an issue where a fault would occur at the detached building I would not want it going back to the house, but going to the driven grounding rods.

No, you want the fault to travel through the feeder back through the house back to the utility transformer. Dirt doesn't conduct very well.

 

[infinity]

I need a clarification on Article 250.32. I have a 100 amp 1 phase sub panel ran to a detached building 225' away from the house. No water line or gas line ran to the new building. I ran 3 lines to the building, drove two ground rods and treated the sub panel as a new service. The Article say you should run a Equipment ground. with the feed conductors, but under the exceptions is says the 4 wire is not needed if these conditions are met, which they all are. Please give me your input. If there was an issue where a fault would occur at the detached building I would not want it going back to the house, but going to the driven grounding rods.

Thanks,

The exception to bond the neutral has been out of the NEC for several code cycles. Unless you're under the 2005 NEC or earlier you'll need an EGC in with the feeder.