Water pipe supplemental grounding electrode(s)?

[Power Solutions]

Hi All,
Had a discussion with the AHJ today.
He is under the impression that if I am using a municipal (metal) water pipe as my primary grounding electrode that I must install two supplemental ground rods according to 250.53.
I do not see it. The way I have always read it, it only requires one supplemental (grounding electrode) ground rod.
We need clarification on this please and thank you.
Dj

 

[Dennis Alwon]

Look a bit further in 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...

 

[infinity]

There are some semantics involved here. You both might be correct. A single ground rod is not considered an electrode unless it's supplemented by another a electrode (can be a second rod) or if the single rod is proven to be 25 ohms or less.

 

[winnie]

And guess which is cheaper: proving a single rod has a resistance to distant earth less than 25 ohms, or simply driving a second rod.

 

[tom baker]

Or "drive two and go home"

 

[LarryFine]

I was told by an inspector on my second service change that I had to drive two rods because I was unable to ascertain that the existing water pipe was metallic and long enough to qualify as an electrode.

On another, more recent job, I was able to use a single existing rod because I was able to prove the new water pipe was metallic and long enough to qualify as an electrode:

 

[Eddie702]

I have an old beater rotary hammer just for that purpose, it usually slams rods in pretty good

 

[infinity]

I was told by an inspector on my second service change that I had to drive two rods because I was unable to ascertain that the existing water pipe was metallic and long enough to qualify as an electrode.

On another, more recent job, I was able to use a single existing rod because I was able to prove the new water pipe was metallic and long enough to qualify as an electrode:

View attachment 2553516 View attachment 2553517 View attachment 2553518 View attachment 2553519

A single rod unless tested to prove that it's 25 ohms or less does not qualify as an electrode.

 

[LarryFine]

A single rod unless tested to prove that it's 25 ohms or less does not qualify as an electrode.

I normally do two. I'm just relating what I was told on two specific jobs.