Common GEC for 2 Family Dwellings

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stonecutter

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Hello All. I have a 2 family dwelling. Two separate 100A services. I have spliced at the overhead service point, two separate #2 aluminum SE cables. I terminated each cable into its' own utility meter. From the meters I have run a separate SE cable to each 100A main service panel. I am going to use #6 copper for my GEC.
Can I run one #6 copper grounding electrode conductor from one main service grounding buss to the other main services' grounding buss, then to the water pipe (water utility is common to both) and ground rod? I would consider this a tap and my references are NEC 2014 250.64(C); 250.64 (D)(1), (D)(2) or (D)(3) and 250.64(F)(1). They are separate services and and are in individual enclosures. Basically, I am going to daisy chain a #6 copper GEC from one main panel to the other main panel, then onto the water pipe and ground rod.
 
did not check to see if 6 AWG is acceptable for the GEC, but otherwise is one way to do it.

You can also make taps from each disconnect to a common GEC, or run one GEC to a common point ahead of your service disconnecting means - like to the point where the service drop connects to the mast(s) or risers.
 
IMO, the neutral bar is not an acceptable means of splicing the grounding electrode conductor. 250.64 (C) mentions buss bar not neutral bar
 
Understood about the busbar being a more acceptable method. But, what I am doing is providing a grounding electrode conductor from one 100A main to the other 100A main. Although there is not a busbar, I would be using a terminal that is listed as grounding and bonding equipment.
And yes, according to table 250.66, a #6 copper conductor is the correct size GEC for a #2 aluminum service entrance conductor, without providing the physical protection a #8 would require.
Thanks for the responses.

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stonecutter said:
Understood about the busbar being a more acceptable method. But, what I am doing is providing a grounding electrode conductor from one 100A main to the other 100A main. Although there is not a busbar, I would be using a terminal that is listed as grounding and bonding equipment.
And yes, according to table 250.66, a #6 copper conductor is the correct size GEC for a #2 aluminum service entrance conductor, without providing the physical protection a #8 would require.
Thanks for the responses.

Sent from my Moto G (4) using Tapatalk
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But don't you have 2- #2 SE conductors (per ungrounded conductor). Didn't check it out but is probably still small enough but about has to be getting near needing a larger GEC.
 
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