Thanks Stamcon for bringing to light the Green Book. The Electric Services Requirements book was the only publication provided to me by PGE, and no mention of the Green Book was made. I've been planning to visit my PGE office soon in order to get an updated copy of the Service Reqs., and now I can ask them about why their advice differs from one publication to another. I suppose the Service Req book neglected to mention that their prohibition against joint electric and gas pertained to just non-PGE gas lines.
Anyway, as Caselec mentioned, it has to be checked out locally. In light of the Green Book info, there doesn't seem to be any big objection to running gas and electric at least 6" away from each other...enough to not dig up one when trying to dig up the other.
