I'll give UL a call next week seeing how they list both as acceptable for grounding.
Maybe they have data on it.
"As for getting large compression couplings to tighten properly, the trick I've found is to use two strap or pipe wrenches that you think are completely too big for the job."
Used two pair of 480s, two men, and still had conduits turning in couplings behind us.
The couplings did'nt seam loose but the conduit would turn unless you put a wrench on it.
This is over 2000 foot of 3 1/2 in a little over a year.
I've had alot of practice.
Edit to add, that all of these runs had redundant equipment grounds. Grounding must not be the reasoning for these specs.
Maybe it's, MUST BE BETTER it's used out side, and their harder to use.
[This message has been edited by russ m (edited 11-25-2005).]
