Mechanical Bonding 2 seperate load centers (same service)

[Rford1985]

My discussion/question is in regards to bonding mechanical equipment to the electrical service at a residential setting. Per Indiana Residential code, we are required to bond metallic gas lines and water lines. So typically, if I'm installing a 400amp service with (2) 200amp main breaker load centers, I would install a #4 grounding electrode conductor from each 200amp panel to grounding electrode(s) (groundrods). Then for gas/water lines, I would install a #4 from each panel to the gas line and a #4 from each panel to the water line. (so you end up with (2) #4's attached to the water line and (2) #4's at the gas line) My question is, is this actually necessary, or could I just run (1) #4 to gas and (1) #4 to water from one of the load centers, and then jump another set of #4's from 1st load center to the other? Hopefully my description/question isn't too confusing. Please let me know how you guys would typically do this...

 

[Greentagger]

Please refer to 250.104(A)(1)(1)-(4), and 250.104(B)(1)-(5). Key words also include “likely to become energized”. Normally the EGC in the branch circuit that supplies that equipment will suffice and provide the bonding. Sorry, not familiar with your Indiana Residential Code requirements.

 

[suemarkp]

Water pipe bonding is sized like a GEC. what I did with mine was run a 1/0 copper to the water pipe from one of the panels. The only issue I had was finding a water pipe clamp that would take a conductor larger than #2. Eventually I found one at home depot that was cheap.

Gas pipes may only need to be sized to #6 copper if they want a contingent bond for CSST piping. Ask your locals what they want for gas pipe bonding. Otherwise, it is the circuit EGC that can bond gas pipes.