Southwire 250 ft. 12/2 Solid Romex SIMpull CU NM-B W/G Wire250 ft. 12 2 Solid Romex SIMpull CU NM B W G Wire Type NM B (nonmetallic sheathed cable) may be used for both exposed and concealed work in normally dry locations at temperatures not to exceed 90 degree C (with Ampacity limited to that for 60 degree C conductors) as specified in the NEC 1. NM B cable is primarily used in residential wiring as branch circuits for outlets, switches and other loads. NM B cable may be run in air voids of masonry block or