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Subject - Supplemental grounding
karlwayne Art. 250.53(C)(2) basically states that a ground rod must supplement the use of a water pipe electrode, and that the ground rod must comply with "art. 250.56."

Article 250.54 states that a supplementary ground rod is not required to comply with 250.56.

Can you help clarify this
iwire I will give it a try.

First we have to notice that the NEC is using two different words that sound close but to the NEC have entirely different meanings.

Supplemental

and

Supplementary

A Supplemental electrode is a required electrode and must be installed meeting all code sections.

quote:
250.53 Grounding Electrode System Installation.

(D) Metal Underground Water Pipe. Where used as a grounding electrode, metal underground water pipe shall meet the requirements of 250.53(D)(1) and (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)(7). Where the supplemental electrode is a rod, pipe, or plate type, it shall comply with 250.56. The supplemental electrode shall be permitted to be bonded to the grounding electrode conductor, the grounded service-entrance conductor, the nonflexible grounded service raceway, or any grounded service enclosure.

Exception: The supplemental electrode shall be permitted to be bonded to the interior metal water piping at any convenient point as covered in 250.52(A)(1), Exception.


On the other hand a Supplementary electrode is an optional one, you do not have to install it and even if you do it can be installed in any way you choose. It could be a 4' piece of rebar thrown in the ground and connected to the equipment grounding conductor with 12 AWG.



quote:
250.54 Supplementary Grounding Electrodes.
Supplementary grounding electrodes shall be permitted to be connected to the equipment grounding conductors specified in 250.118 and shall not be required to comply with the electrode bonding requirements of 250.50 or 250.53(C) or the resistance requirements of 250.56, but the earth shall not be used as the sole equipment grounding conductor.
Ryan_J An example of a supplementary electrode might be a ground rod in a light pole base, or a piece of IT equipment that for some reason wants a ground rod driven within a couple feet of it.

Bob's answer is right on the money, I just thought I'd throw in an example.
karlwayne I thank you
cs409 Main Entry: sup·ple·men·tal
Pronunciation: "s&-pl&-'men-t&l
Function: adjective
1 : serving to supplement

Main Entry: 1sup·ple·ment
Pronunciation: 's&-pl&-m&nt
Function: noun
1 : something that completes or makes an addition

Main Entry: sup·ple·men·ta·ry
Pronunciation: "s&-pl&-'men-t&-rE, -'men-trE
Function: adjective
1 : added or serving as a supplement


any thoughts???
JimmyDee
quote:
any thoughts???

The writers of the code are not proficient in art of linguistics. They have done a good job defining what they meant in this case.
Jim