Conduits

An electrical conduit is a tube used to protect and route electrical wiring in a building or structure. Electrical conduits may be metal, plastic, fiber, or fired clay. Most pipes are rigid, but the flexible tube is used for some purposes. Conduit, channel, or pipe for conveying water or other fluid or carrying out other purposes, such as protecting electric cables. In water-supply systems, the term is usually reserved for covered or closed sections of the aqueduct, especially those that transport water under pressure. Large conduits may be fabricated of steel sections joined in the field of reinforced concrete, often precast and pre-stressed, or driven at depth through solid rock, for example, under mountainous terrain or rivers. Smaller pressure conduits are usually cast iron, steel, or asbestos cement. Pressure conduits are generally kept below the hydraulic grade line—that is, the line representing the height to which the water would rise if free—to avoid possible air entrapment.