منتدى الهندسة الكهربية

Types of ****l C**duit

Rigid Steel C**duit

Rigid steel c**duit is a heavy duty variety of pipe, available in ½- to 6-inch interior diameters, used to carry electrical cables in areas where physical damage to the pipe is likely and the extra strength of rigid steel is required for piping to survive. This c**duit resembles ****l pipes used to carry water and comes in 10-foot lengths with threads at each end for c**necting pipes together. A galvanized versi** of this steel c**duit is available for wet and damp areas and underground applicati**s. The galvanizing treatment prevents pipes from rusting and weakening from moisture damage. Rigid steel c**duit is subject to the U.S. Nati**al Electric Code (NEC secti** 349). This guide lays out rules and regulati**s regarding tolerances and specificati**s. In some cases, electrical wiring can be grounded using rigid steel c**duit.

Flexible ****llic C**duit (FMC)

Flexible ****llic c**duit is formed from coiled or wound, interlocking and ribbed strips of ****l such as steel or aluminum. It bends to facilitate installati** where the extra protecti** of ****l c**duit is required. FMC does not retain the shape it is bent into. Its uses include dry locati**s where c**duits without flexibility could fracture under pressure, in areas where earthquakes are comm**place, for example. FMC c**duit is available in 10-foot secti**s. Cutting this pipe requires a special power tool fitted with a rotary abrasi** disc that makes very small cuts in the outer ****l wall because the larger tools could sever the sensitive wires this c**duit carries. According to NEC regulati**s, FMC can be used as an electrical grounding tool.

Electrical ****l Tubing (EMT)

Electrical ****l tubing is light-gauge pipe, also known as thin-walled c**duit, and used for applicati**s where the thicker rigid steel c**duit is not required. In comparis** with the heavier types, EMT has walls that are roughly 40 percent thinner. This lighter c**structi** and thinner weight allows EMT to bend easily for c**structi** purposes. Article 348 in the NEC covers EMT c**duit. Lengths of EMT are a standard 10 feet l**g. Interior diameters are between ½ to 4 inches.