Can't find a code section to verify this printed article

[macmikeman]

I was reading the April 2007 Code article in Electrical Contractor magazine authored by George W. Flach, and this caught my eye. "Where there is 10 feet or more of buried metal water pipe, the grounding-electrode conductor cannot be smaller than 2 AWG copper. Table 250.66 is used to size the grounding-electrode conductor where a metal water pipe is the grounding electrode. In addition, the metal water pipe must be supplemented by one or more of the following: the metal frame of a building, a concrete-encased electrode, ground ring, rod, pipe or plate electrodes." I think this is in error regarding the minimum size of #2. If the largest service conductor is a #2, then the minimum size of the gec per Table 250.66 is #8 copper.

 

[infinity]

I think this is in error regarding the minimum size of #2. If the largest service conductor is a #2, then the minimum size of the gec per Table 250.66 is #8 copper.

I agree. #2 SEC's would require a #8 GEC to the water pipe.

 

[celtic]

Here is the article from ECMag:

Grounding-electrode conductor size
by George W. Flach
Published: April 2007

The question is:

Q: Where the sizes of service-entrance conductors are increased to reduce voltage drop, does the National Electrical Code (NEC) require an increase in the size of the grounding-electrode conductor (for example, a service that consists of 250 Kcmil copper conductors protected by a 150-ampere circuit breaker)?

In the example, wouldn't the 250KCMs require a #2 per T250.66 ?

 

[infinity]

In the example, wouldn't the 250KCMs require a #2 per T250.66 ?

Yes it would, but the OP says #2 SEC's.

 

[celtic]

I don't know where the #2 service conductors came from...they have nothing to do with the article in ECMag....

" I think this is in error regarding the minimum size of #2."

Two different questions...two different answers.

 

[Dennis Alwon]

Celtic read further in the article. The quote paragraph is what the OP is referring to but I think it was taken as a stand alone rather than as part of the question above it. I think the op just read the paragraph but didn't realize it is referring to the question above it.

Where there is 10 feet or more of buried metal water pipe, the grounding-electrode conductor cannot be smaller than 2 AWG copper. Table 250.66 is used to size the grounding-electrode conductor where a metal water pipe is the grounding electrode. In addition, the metal water pipe must be supplemented by one or more of the following: the metal frame of a building, a concrete-encased electrode, ground ring, rod, pipe or plate electrodes.

Table 250.66 must be used to size the grounding-electrode conductor that is run to the metal water pipe electrode. The title for the table is ?Grounding Electrode Conductor for Alternating-Current Systems,? and the title for the left-hand column is ?Size of Largest Ungrounded Service-Entrance Conductor or Equivalent Area for Parallel Conductors (AWG/Kcmil).? Notice the table is based on the size of the service-entrance conductors, not on the overcurrent protection at the termination of the service-entrance conductors.