Classes A, B, C, D, G, and M. 1  Classes A â C permit operation of motor vehicles based on GVW rating and must be renewed every 5 years. 2  Classes D and G are valid for operation of a single motor vehicle with a GVW rating of 26,000 lbs. or less.
Electrical Metallic Tubing (EMT) Electrical metallic tubing (EMT), also commonly called thin-wall, is a listed steel raceway of circular cross section, which is unthreaded, and nominally 10â² long. 20â² lengths are also available. Covered by Article 358 of the NEC, EMT is available in trade sizes 1/2 through 4.
A conduit is a metal pipe that houses electrical wires. When wires are tightly wound through a conduit, a grounding wire isn't necessary -- as the conduit itself acts as a ground. (It's important to use conduit when running wires on the outside of a wall.) Conduit benders will bend the metal of a conduit, or a 90 degree pulling 'L' can be used (image 1).