Rigid, formally rigid metal conduit or galvanised rigid conduit, is thick-walled steel pipe threaded on both ends with a tapered thread and joined with threaded couplings. It shrugs off physical damage, can be buried or encased in concrete, and is required in many hazardous locations and is the usual pipe for service masts. It is bent with hickeys and mechanical or hydraulic benders and cut and threaded on site, and it weighs noticeably more than IMC, its thinner threaded cousin.
Service mast has to be two-inch rigid, thread it on the machine and set the weatherhead high enough to clear the drop.
Also heard as
- RMC
- GRC
- heavy wall
- galv
Related terms
EMT
Electrical metallic tubing: thin-wall, unthreaded steel conduit joined with set-screw or compression fittings.
Hickey
Short-headed hand bender for rigid conduit, and also the threaded fitting that hangs a fixture from a box stud.
Erickson
Three-piece union that joins two lengths of threaded rigid conduit when neither one can be turned.
Nipple
Short length of conduit, threaded or with fittings on both ends, connecting two nearby boxes or enclosures.