Detached Garage Steel Gas Line Difference of Potential

[hoots]

Recently bought a house and There was a detached garage with a existing gas line (steel black pipe) and sub panel with a 4 wire feeder. Opened up the panel and of course they bonded the neutral to the box. Removed The Bonding screw and seperated the Grounding & Grounded conductor. My issue is with the grounded conductor not yet landed, i'm still getting 120v from phase to conduit\steel panel.
-Gas line Hard Piped to garage furnace from house underground
-Conduit to furnace

I'm concerned that there is a difference in potential to ground. I even went as far as pulling the individual branch circuit neutrals off the bus bar and still get 120v to neutral . Seems i need to start opening boxes up and investigating.

My question is how to properly isolate Neutral from Ground\Bond in this situation. Should i check to see if they bonded the gas line to the main panel? Steel gas line goes directly to earth. Hope someone has come across this before, and knows the solution.

Also, The you tube videos Mike put out are GREAT and very informative! Keep up the good work!

 

[hoots]

My issue is with the grounded conductor not yet landed, i'm still getting 120v from phase to conduit\steel panel.

Grounding conductor^^^

 

[ActionDave]

Black iron buried underground is a problem all on its own.

There will always be a difference in potential between any ungrounded/hot conductor and anything grounded. Then there is the whole thing with digital meters.