2 ground rods

[jar546]

OK, I'll assume my confusion is in a change from 2008 to 2011....I'm still on the 2008 which allows a metal water pipe and 1 additional electrode in lieu of a resistance test.

I am talking about the 2008. Makes no difference 08 or 11

I was schooled on this in 2009 by Mr. Johnston

 

[Dennis]

OK, I'll assume my confusion is in a change from 2008 to 2011....I'm still on the 2008 which allows a metal water pipe and 1 additional electrode in lieu of a resistance test.

I think this is where your problem lies. Black bold in art. 250.53(D)(2) below tells us we must have one additional electrode for a water pipe-- don't stop there. The reddish brown part states that if the extra electrode is a rod, pipe or plate then it must comply with 250.53(A). Art. 250.53(A)(2) below (the blue part) says that a single rod must be supplemented by another rod or....

The green states one rod is fine if we get 25 ohms--- only if one rod gets 25 ohm may we ignore the second rod. Hope this helps

250.53(D)(2)(2) Supplemental Electrode Required. A metal underground water pipe shall be supplemented by an additional electrode of a type specified in 250.52(A)(2) through (A)(8). If the supplemental electrode is of the rod, pipe, or plate type, it shall comply with 250.53(A). The supplemental electrode shall be bonded to one of the following:

(1) Grounding electrode conductor

(2) Grounded service-entrance conductor

(3) Nonflexible grounded service raceway

(4) Any grounded service enclosure

(5) As provided by 250.32(B)

250.53(A) Rod, Pipe, and Plate Electrodes. Rod, pipe, and plate electrodes shall meet the requirements of 250.53(A)(1) through (A)(3).

(1) Below Permanent Moisture Level. If practicable, rod, pipe, and plate electrodes shall be embedded below permanent moisture level. Rod, pipe, and plate electrodes shall be free from nonconductive coatings such as paint or enamel.

(2) Supplemental Electrode Required. A single rod, pipe, or plate electrode shall be supplemented by an additional electrode of a type specified in 250.52(A)(2) through (A)(8). The supplemental electrode shall be permitted to be bonded to one of the following:

(1) Rod, pipe, or plate electrode

(2) Grounding electrode conductor

(3) Grounded service-entrance conductor

(4) Nonflexible grounded service raceway

(5) Any grounded service enclosure

Exception: If a single rod, pipe, or plate grounding electrode has a resistance to earth of 25 ohms or less, the supplemental electrode shall not be required.

 

[mjf]

Thanks Dennis.

Right after I hit enter, I pulled out my code book and dug into those sections.