Conduit is a term used for hollow channels designed to enclose and protect cable. Conduit shields conductors from physical damage. Conduit is referred to by “trade size”. Common trade sizes range from 3/8″ to 6”, according to its inside diameter. The size of conduit needed depends upon the number and size of conductors the conduit will be holding. Conduit provides flexibility in the number and size of the conductors installed. If electrical requirements of the structure should change, conductors can be easily removed. If a short is suspected, individual conductors can be removed and inspected. There are three types of conduits: Rigid metal conduit (Rigid), Intermediate metal conduit (IMC), Electrical metallic tubing (EMT).