Multiple Services in the same building

[xxtalljimxx]

I recently installed a 200 amp three phase service and a building with an existing 200 amp single phase service. I took a grounding electrode conductor to a new 8' ground rod that i installed. I ran a #4 bare to the steel which a idrilled and tapped. I am just confused about the water pipe. Since the other service is ran to within 5 feet of enetering the building and the meter is jumped out; do i have to run a #4 over there also or can i just clamp onto anywhere on the cold water pipe? This really has me stumped and unfortunately my code book is in a gangbox on another job at the moment.

 

[Dennis Alwon]

Here is what I found

250.24 Grounding Service-Supplied Alternating-Current Systems.
(A) System Grounding Connections. A premises wiring system supplied by a grounded ac service shall have a grounding electrode conductor connected to the grounded service conductor, at each service, in accordance with 250.24(A)(1) through (A)(5)

.

 

[tryinghard]

I believe 250.58 "Common Grounding Electrode" applies with your case because you have separate services to one building. You don?t have to install more electrodes just connect to the electrode, all the other electrodes (if there are any others) have to be bonded together and sized per 250.66 and in keeping with 250.53(C ).

250.58: ?Where separate services supply a building and are required to be connected to a grounding electrode, the same grounding electrode shall be used.?

You can connect to any one of the electrodes, but they do need to be connected ?effectively bonded? together with a correctly sized conductor per Table 250.66.

 

[Dennis Alwon]

I agree so the ground rod that you drove must be connected to the rest of the electrodes in the building. It cannot stand alone