It is impractical, and prohibited by wiring regulations, to have more than 360 degrees of total bends in a run of conduit, so special outlet fittings must be provided to allow conductors to be installed without damage in such runs. Conductors installed within conduit cannot dissipate heat as readily as those installed in open wiring, so the current capacity of each conductor must be reduced (derated) if many are installed in one conduit. In applications such as residential construction, the high degree of physical damage protection may not be required, so the expense of conduit is not warranted. The cost of conduit installation is higher than other wiring methods due to the cost of materials and labor. Special tube bending equipment is used to bend the conduit without kinking or denting it. This is particularly advantageous when following irregular or curved building profiles. For example, retail display cases and open-office areas use floor-mounted conduit boxes to connect power and communications cables.īoth metal and plastic conduit can be bent at the job site to allow a neat installation without excessive numbers of manufactured fittings. This is commonly used in commercial buildings to allow electrical and communication outlets to be installed in the middle of large open areas. Some types of conduit are approved for direct encasement in concrete. When installed with proper sealing fittings, a conduit will not permit the flow of flammable gases and vapors, which provides protection from fire and explosion hazard in areas handling volatile substances. Non-metallic conduits resist corrosion and are light-weight, reducing installation labor cost. Metal conduit can be used to shield sensitive circuits from electromagnetic interference, and also can prevent emission of such interference from enclosed power cables. Frequent wiring changes are made simpler and safer through the use of electrical conduit, as existing conductors can be withdrawn and new conductors installed, with little disruption along the path of the conduit.Ī conduit system can be made waterproof or submersible. Wiring systems in buildings may be subject to frequent alterations. Varying numbers, sizes, and types of conductors can be pulled into a conduit, which simplifies design and construction compared to multiple runs of cables or the expense of customized composite cable. Its use, form, and installation details are often specified by wiring regulations, such as the US National Electrical Code (NEC) and other building codes.Ĭomparison with other wiring methods Įlectrical conduit provides very good protection to enclosed conductors from impact, moisture, and chemical vapors. Most conduit is rigid, but flexible conduit is used for some purposes.Ĭonduit is generally installed by electricians at the site of installation of electrical equipment. Electrical conduit may be made of metal, plastic, fiber, or fired clay. ![]() ![]() Conduit embedded in concrete structure for distribution of electrical cables throughout this highrise apartment building Electrical conduit and bus duct in a building at Texaco Nanticoke refineryĪn electrical conduit is a tube used to protect and route electrical wiring in a building or structure. Raceways are used to protect electrical cables from damage. The firestop is made of firestop mortar on top and mineral wool on the bottom. This illustration shows electrical conduit risers, looking up inside a fire-resistance rated shaft, as seen entering bottom of a firestop.
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