Bonding water pipe on 21 unit apartment

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jerrysounds

jerrysounds

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San Diego
I am upgrading a 21 meter,400 amp service do to corrosion(apartment units are located 4 blocks from the ocean). Each unit has a 50amp sub panel and has its own water meter, located along the entire length of the building (200ft). When the apartments were originally built they did not bond the water pipes for each unit. I am going to bond the 21 unit pipes together from the bonding lug located at the main disconnect. My question is, what do I size my bonding wire to, the 50 amp sub panels for each unit( no larger than #6, 250.66A), or the 400 amp service(#1/0, Table 250.66). I'm leaning towards the #6(1/0 is going for $2.50+ a foot). Thanks for your help. Happy Holidays
 
jerrysounds said:
My question is, what do I size my bonding wire to, the 50 amp sub panels for each unit( no larger than #6, 250.66A)
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250.66(A) is ONLY for Rod, Pipe, or Plate Electrodes as allowed by 250.52(A)(5) or (6), that portion of the conductor that is the sole connection shall not be required to be bigger than #6...

If your using the water pipe as a Grounding Electrode, then you would size the conductor with table 250.66
 
Thanks for the reply Stickboy. I see that because it is not nonmetallic water piping for each unit I can not use table 250.122. I must use table 250.66 (250.104A 2,3). Can anyone see a way around this?
 
stickboy1375 said:
Have the plumber install pvc sections to isolate the individual units....
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I wouldn't want to get the bill for that. Plumbers actually charge real prices and know how to make money!
 
Is the metallic piping continuous?

What I'm wondering is, can you connect the 1/0 GEC once to the water pipe, and then jumper the water meters with a bunch of short 1/0 bonding jumpers?

I don't see a way to use 250.104 with #6's in this situation, even though it makes sense. :rolleyes:
 
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