Grounding electrode clarification

[nizak]

Have a question regarding GE system. If a copper water line is used as a grounding electrode and there is footing re-bar also available, does there still need to be a driven rod? What would the proper system consist of if water came in as plastic
and the re bar is present? I'm working in two different municipalities, one is requiring the driven, the re bar, and the copper water, the other is requiring any 2 of the three I named. To my knowledge neither of the two AHJ's are doing any type of Ohm's check on the system. In either of the scenarios I've listed, the footing re bar is always present. Thanks much.

 

[iwire]

If you have concrete encased electrode there is no NEC requirerment for a driven rod with either a metal or plastic water main.

 

[nizak]

Somewhere I always thought that (2) grounding electrodes was a requirement. You are saying that if the main is plastic, only the concrete encased is required to be code compliant?

 

[SparkyHC]

Somewhere I always thought that (2) grounding electrodes was a requirement. You are saying that if the main is plastic, only the concrete encased is required to be code compliant?

Yes, iwire is correct..NEC 250.53 (D)(2) requires grounds rod(s) as supplemental to the underground metal water pipe...
If the Concrete encased electrode is used then there are no requirements for ground rods...

 

[ActionDave]

Somewhere I always thought that (2) grounding electrodes was a requirement.

A lot of old timers think the same way.....my boss is one of them.

You are saying that if the main is plastic, only the concrete encased is required to be code compliant?

What they said is correct.

 

[Sahib]

Unfortunately, the concrete encased electrode is not a made electrode like a ground rod. You can not make use of it unless it is made available during the construction of a building.

 

[SparkyHC]

After construction...

After construction...

Unfortunately, the concrete encased electrode is not a made electrode like a ground rod. You can not make use of it unless it is made available during the construction of a building.

Actually in New Jersey, and other states I would expect, you can add a concrete encased electrode to a
project after the footings are done...
The following is a Bulletin from NJ DCA:

B U L L E T I N 02-2

The Department of Community Affairs has assigned the building subcode
official/inspector responsibility for the inspection of bonding connections to
the rebars. This can be accomplished during inspection of the footings before
the concrete is poured. As outlined in the Electrical Subcode, Section 250.70,
this involves inspecting a listed clamp that connects the rebar of a specified
size, which is located at the bottom of the footing and will remain in direct
contact with the earth, to a solid or stranded copper conductor of size 4 AWG,
as specified in the Electrical Subcode, Section 250.66(B). The 20 feet of rebar
can be one continuous piece, or many pieces tied together by tie wires to form
a continuous length of 20 feet or more.

A concrete-encased electrode can also
be a 4 AWG bare copper conductor at least 20 feet long that is encased in 2
inches of concrete in or near the footing. Field inspection of this installation by
a building inspector does not require any specialized training.

 

[Sahib]

Thanks, sparky for your reply.
My point is if the building construction is over, digging into the ground near footings for placing concrete encased electrode may damage the footings and so should not be done.