OK thought about it, and theres something wrong here....
TWO WIRE PANEL?! Hot (1), neutral (1), thats it?
Fed with 2/0, or 3/0? Either way, next question is... how is the other side of the panel fed? Double lugged? From a 100A single pole breaker? One phase dead? Or is the only time I'll hear about a 120 only panel?
What will it take to get the other two conductors there.
Anyway, steel structure, no ground! With no fault path, a short circuit could kill someone coming out of the rain, and locking their hand around an energized door knob. Forget anything in regaurds to lightning, although also a hazard, it is more remote than the chances of other (in this case likely) electricution hazards. Like.... an HID, or flouresant fixture imposing 300-1200 volts on the metal surfaces of the building. Or, if someone, and it is likely here, that the nuetral is bonded to the panel can by the stupid screw that comes with them, that it is a parralel path for neutral current. A few minutes with a calculator with known loads, and I could give you an rough estimated amperage of a bare foot hippy leaning against the wall. (No offense to hippies who wear shoes.....)
If this is in conduit, yank out the the 2/0, or 3/0, and give it a #2 THHN feed, with 3-wires and a #6 ground. Or the other method described in 250.32 (Ground rod, neutral bond, AND bond the steel.) Depending if there is a metalic path between this shock chamber, and the main building. www.markhellerelectric.com/250.32.pdf
[This message has been edited by e57 (edited 04-19-2005).]