Water Ground

[1793]

If the Driven Ground conductor max size is #6, what size is used for the Water Ground, within 5 feet of the entrance to the dwelling?

If different what is the reference?

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[bphgravity]

Re: Water Ground

Grounding electrode conductors are sized from Table 250.66.

Only rod, plate, pipe, concrete-encased, and ground ring electrode conductors have a maximum required size. All the other permitted electrodes should be size from the table, including water pipes.

 

[1793]

Re: Water Ground

I thought I would use 250.66. I have a garage, detached, with a new underground 200 amp service from the pad. There will be NO water available. What is the most widely accepted method to ground this type of installation?

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[bphgravity]

Re: Water Ground

Any of the allowable grounding electrodes as specified in 250.52(A).

 

[1793]

Re: Water Ground

Bryan:

250.52(A)(5) Rod & Pipe Electrodes. I have been using Copper Ground Rods (5/8") with #6 as Driven Grounds.

Do I read this correctly that I can use this Cu rod buried 30" deep horizontally and then use #4 for the Conductor as the sole Grounding System?

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[bphgravity]

Re: Water Ground

CU ground rods are permitted to be 1/2 in. 5/8 are more than adequate.

You technically can't just arbitarily bury a ground rod 30 in deep without first trying to drive the rods vertically, and then at angles up to 45 degrees. See section 250.53(G)

A #6 is still the maximum required electrode conductor required to a ground rod whether its driven or buried.

 

[1793]

Re: Water Ground

Bryan:

The installation is in an area where I KNOW that rock bottom is less that 8'. I hate to beat a dead horse but I'm trying to do a correct, safe, installation. Even though the service feeder is rated for 200 amps, 1/0CU or 4/0AL, and Table 250.66 lists the GEC as #4, with the grounding system only consisting of the driven, buried, then #6 is all I HAVE to use?

Thanks for working with me on this.

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[bphgravity]

Re: Water Ground

That's fine then. Here in coastal Florida, all you have to do is hit a ground rod about three times to get it 8' down! Obviously, the known geography of the area will dictate how installations will be made.

Yes, a #6 GEC to a ground rod is the maximum size required no matter what the size of the service entrance. You can run a #4 or larger to a ground rod, but it will not be any more effective than the #6.

 

[1793]

Re: Water Ground

Bryan:

I'm sorry it has taken me so long to get back with you to thank you for your time and expertise. The information you provided has helped me understand this somewhat confusing situation.

Again, thank you.

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[bphgravity]

Re: Water Ground

No problem Norb. I'm glad I could help.

Click on the search function above, put in a topic, and you will find endless information. Feel free to post any questions you have, and post answers to other's questions.

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