Bonding underground fuel tank to GES

[wbalsam1]

If there is a metal underground fuel tank at a single family residence and this tank has metallic piping that extends into the basement of the dwelling, would bonding the interior piping with a conductor sized in accordance with 250.66 satisfy 250.52(A)(8)? Sure seems it to me.
I see a lot of fill and vent pipes that are not bonded, though. :smile:

 

[mdshunk]

Chances are that piping is already bonded at the burner motor.

 

[wbalsam1]

Okay, here's an interesting question (at least to me it is:smile.
Got a SFR with plastic water service piping, no building steel and the foundation is pressure treated wood on stone/gravel, so no CEE. It's wired under the '08 NEC, which at 250.50 states where none of the above grounding electrodes exist, one or more of the grounding electrodes specified in 250.52(A)(4) through (8) shall be installed and used. Those are ground ring, rod and pipe, other listed GE's, and other local underground systems or structures.
I pick the underground fuel tank as part of the GES. I believe I would have to size the GEC as per 250.66 and not be able to rely on the equipment grounding conductor within the branch circuit to the boiler motor. Yes? :smile:

 

[hardworkingstiff]

Most underground storage tanks (UST) come with dielectric bushings in their openings to try to prevent the tank being involved in a corrision cell. It's possible by bonding the UST, you may significantly shorten the life span of the UST. I've wired a lot of gas stations, and the only time the tank was bonded was when anodes were installed around the tank and the tank was bonded back to the rectifier of the impressed current system. The tank should be manufactured so it will not be in contact with the earth it is buried in.