full of galvanized steel conduits for cable wiring joint with electrical box.load panel three-phase electric power, main distribut

airport background board box boxload building bus business cable column conduit conduits connector construction control coupling distribut distribution electric electrical electricity emt engineer engineering equipment escalator facility floor frame full galvanized glass industrial industry inside interior joint light main mdb metal metro panel pillar power room roomconcept stairs station steel subway technology threephase train transport transportation tunnel underground urban wiring