Ground conductor question

[alaskanassassin]

I started wiring a house for a friend and before I got there they had a 200 amp single phase service already put up on a pole. The house is 250 feet away. They purchased three 3/0 direct burial cables and proceeded to bury it with no ground. I am considering digging a new trench and running a #6 ground between the house and pole, is this the correct thing to do? Thanks

 

[jbelectric777]

If the service conductors are outside and buried without overcurrent protection its legal. Drive the rod @ the house for the main panel. The wires are considered "outside of building" hence not a feeded but service entrance.

 

[roger]

What code cycle are you under?

Roger

 

[roger]

If the service conductors are outside and buried without overcurrent protection its legal.

The service is on the pole per the OP.

Roger

 

[alaskanassassin]

In addition to running a new ground cable, I installed a ground rod at the service and another ground rod at panel of the house, I am told this is going to create a parallell ground path is this right?

 

[zbang]

If the service is really on the pole (disconnect, bond, grounds, and all), then this is a feeder, not a service lateral. Is the service live already? Permitted/inspected?) What code cycle? That makes a big difference here. How deep are they buried? If you can't guarentee that their work is to code, put something in writing that you're only responsible for the work that you do, and this wasn't included. (Yes, I'd even do this to a friend.)

 

[raider1]

In addition to running a new ground cable, I installed a ground rod at the service and another ground rod at panel of the house, I am told this is going to create a parallell ground path is this right?

No, there is no issue with installing a grounding electrode system at both the service and at the home.

In fact 250.32 (A) specifically requires that you have a grounding electrode system at a detached building supplied by a feeder.

Now back to Roger's question, what code cycle are you working under?

If you are under the 2005 NEC or an earlier code, then provided that there is not bonded metallic path between the 2 structures you can use the grounded conductor for bonding purposes at the detached building that is supplied by the feeder. (This would be 250.32(B)(2) in the 2005 NEC)

Chris

 

[alaskanassassin]

This is under the 2008 code. Can someone give me an example of a parallel ground path?

 

[augie47]

This is under the 2008 code. Can someone give me an example of a parallel ground path?

One example would be if you had bonded to a metallic water pipe at the pole and to the same water pipe at the house.
Current traveling thru the earth between two ground rods is not considered a parallel path.
Prior to '08 this would give reason to install the equipment ground that you installed, once '08 was adopted the EGC was required regardless.

 

[roger]

Another example could be a telephone wire or coax between the pole and the house.

Roger

 

[zbang]

Sounds to me like the only proper thing to do is dig up the existing conductors and drop a properly sized EGC to the same trench (250.32B "with supply conductors").

I don't think you can use the exception in 250.32B to use a separate trench.