WW-C-00540C(GSA-FSS), INTERIM FEDERAL SPECIFICATION, CONDUIT, METAL, RIGID: AND COUPLING, ELBOW, AND NIPPLE, ELECTRICAL CONDUIT: ALUMINUM (15 MAY 1967

WW-C-00540C(GSA-FSS), INTERIM FEDERAL SPECIFICATION, CONDUIT, METAL, RIGID: AND COUPLING, ELBOW, AND NIPPLE, ELECTRICAL CONDUIT: ALUMINUM (15 MAY 1967)., This specification covers aluminum electrical conduit, couplings, elbows, and nipples and shall be of but one grade.