Emt is used as a raceway, the same as Rigid and Intermediate conduit. The biggest differences are the EMT is to thin to be threaded and it is not as durable in corrosive areas. Emt is mainly used indoors, but is also used outdoors above grade.
Russ
http://www.alliedtube.com/html/mechdiv.html http://www.wheatland.com/wtchp.htm [This message has been edited by russ m (edited 06-07-2003).]