Rods and Ufer

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almcvay

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I have a 1000 amp single phase service. It is feed from the PoCo w/ 3-4/0 alum per phase.
If I have a # 4Cu. ufer ground and 1 ground rod what size ground wire do I need.
If I read 250-66 right it would be 2/0 copper to the ground rod.
My Eng. is no help he wants to charge more $ For advise.
Some posts on this Forum say a fire riser is not to be used as a ground electrode per NFPA 13. I have been ask to remove the ground from the fire riser in the past.
The Eng. wants a 4/0 copper to the sprinkler main.He also wants 1 # 6 cu to a 3 rod Delta I think it needs to bond the sprinkler with 2/0 cu or 4/0 alum per 250-120
Can some help I think i'm going crazzy.
Thanks AL.
 
The CEE (Ufer) never requires larger than a #4 Cu GEC or bonding jumper. {250.52(A)(3)}. If you have a CEE you are not required to install even one ground rod. A ground rod GEC or bonding jumper is not required to be larger than #6. {250.66(A)}. If the building has a metallic water pipe that GEC would need to be sized according to 250.66 based on the size of the largest ungrounded service entrance conductors or equivalent area for parallel conductors. The sprinkler main is a different issue due to a conflict in two different standards.
 
I agree with Rob on the GEC sizing requirements to both the CEE and Ground Rod. #4 max to CEE and #6 max to rods.

While the NFPA 13 prohibits the underground portion of the metal piping system for fire sprinklers from being used to ground the electric system, the same section clearly states that bonding requirements of the piping system must still be in compliance. See section 10.6.8 of the NFPA 13 and 250.104 of the NEC. (Section 4.14 of the NFPA 780 for an LPS.)
 
Ignore what the power company installs, and figure out what the NEC would require you to install for service entrance conductors. Table 250.66 Note 2.

If the engineer requires something above code, install it.
 
Ok. Im with you on the GEC and Ufer Size.
If I bond the Sprinkler it would become a ground rod, Right.
What size bond wire should I use? I can't find a table for bonding sprinklers.
 
almcvay said:
Ok. Im with you on the GEC and Ufer Size.
If I bond the Sprinkler it would become a ground rod, Right.
What size bond wire should I use? I can't find a table for bonding sprinklers.
Click to expand...

IMHO 250.104(A) is for the potable water. I think that 250.104(B) applies. But let's say that I am wrong.

250.104(A)(1) allows table 250.122 to be used for isolated metal water piping systems. So you are correct as to the size. You could take it to the ground rod if it was sized the same but it is not. So back to the service.

If 250.104(B) was used you would have to determine what was likely to become energized then use table 250.122.

Your problem is that you have be directed to exceed the code. So do what the EE wants.
 
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