Introduction to electrical conduits
Electrical conduits are tube or duct used for enclosing electrical wires or cables it is a tubing system which is used for protection and routing of the electrical wiring, it may be made up of metal, plastics, fiber or fired clay, for special purpose flexible conduits are used
Electrical conduits protect electrical cables and wires they are used in every residential and commercial establishment
TYPES OF CONDUIT
It is mainly classified by wall thickness, mechanical stiffness and the material used, the material is chosen for mechanical protection and corrosion resistance…
METAL CONDUITS
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Rigid metal conduits (RMC): it is a thick wall tubing usually made up of coated steel, stainless steel or aluminum
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Intermediate metal conduit: it is a steel tubing which is lighter than RMC it may be threaded
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Electrical metallic tubing (EMT): it is also called a thin wall it is not costly and it is lighter. EMT is not threaded but it can also be used with threaded fittings that clamp to it. These are the most used conduits it is used in indoor and outdoor applications, these conduits are easily bent and it is used for ground connection
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Aluminum conduit: these conduits are common in commercial and industrial applications and it is rigid, aluminum conduits are used where they are exposed to water because aluminum has great corrosion resistive property
** NON-METALLIC CONDUIT**
- PVC polyvinyl chloride conduits: the material which is used to manufacture these conduits are plastics so it is corrosion-resistant, and it resists moisture too, these conduits are lighter and it is less costly when compared to others it is heated and bend it is flame-retardant and resistant to sunlight
- Electrical nonmetallic tubing (ENT): it is non-threaded thin wall corrugated tubing ENT is moisture resistant and flame retardant and we can bend it with our hand
- Liquid flexible nonmetallic conduit (LFNC): these are flame resistant non-metallic tubing these conduits are used in short sections towards the end of the conduit, it is waterproof it resists sunlight and dust.
CONDUIT BENDS
Conduits bends must be done carefully the bends which are done outside the factory must be done carefully bends must not damage conduit or reduce its internal diameter, bends must not exceed 360 degrees of bend per conduit run between handhole or foundation
SADDLE BEND ON METAL CONDUIT
UNDERGROUND CONDUITS
Underground conduits must not be placed less than 18 inches below the surface of the ground and it must not be placed not less than 24 inches in any roadway surface, the depth is measured from the top of the pipe
Conduits placed under railroads must not be placed less than 57 inches
ABOVE GROUND CONDUITS
If the conduits are attached to the wood holes then it must be secured with the appropriate two hole type straps and the straps must not be more than 4 feet apart