The Different Types of Conduits


The Different Types of Conduits

A conduit is a type of raceway used to protect and provide a route. It is required when the wiring is exposed or it can be easily damaged. It provides good protection to enclosed conductors from impact, moisture, and chemical vapors. It also makes replacements safer for electrical contractors as existing wirings can be withdrawn with little disruptions. For neater installation and to minimize excessive numbers of manufactured fittings, conduits can be bent. This is perfect for commercial and residential spaces that have irregular or curved interior designs.

Electrical contractors should be mindful of the specified wiring regulators set by the US National Electrical Code (NEC) and other building codes.

Types of Conduits

Conduits are made of different materials such as metal, plastic, fiber and fired clay, depending on where it will be applied. When the right type of conduit is used, and if it is properly installed with the necessary sealing fillings, this will prevent the exposure of volatile substances from fire and explosion hazards.

Metal Conduits

Metal conduits protect sensitive circuits from electromagnetic interference and water exposure.

Rigid Metal Conduit (RMC): The thickest and heaviest type of conduit made of coated steel, stainless steel, or aluminum. It is commonly used to protect wires under driveways and service feeder installations.

Galvanized Rigid Conduit (GRC): Typically used for commercial and industrial construction, this type of conduit non-combustible and corrosive resistant. Because of its structure, it can be used indoor, outdoor, concealed or exposed.

Intermediate Metal Conduit (IMC): Specifically designed to protect insulated electrical conductors and cables, this type of conduit is used to replace the RMC because it is 30% lighter.

Electrical Metallic Tubing (EMT): Also called thin-wall, the EMT commonly replaces GRC because it is lightweight and more affordable. It does not have threads but threaded fittings can be clamped on it. Like GRC, this is commonly used for commercial and industrial applications.

Aluminum Conduit: Just like the GRC, an aluminum conduit is commonly used in industrial and commercial properties that require something that needs higher resistance to corrosion. Contractors can save as much as 20% per foot as compared to RMC. It can also be readily bent on-site based on the needed radius and direction.

Non-Metal Conduits

Non-metal conduits are resistive to corrosion and lightweight, resulting in reduced installation labor costs.

Polyvinyl Chloride Conduit (PVC): The cheapest and lightest among all the different types of conduit, PVC is commonly used over ground concealed application where high-grade protection isn’t needed for electrical wiring. It is advisable to use for indoor, especially for residential properties; however, it can also withstand different weather conditions as it resists moisture and many corrosive substances. For underground applications, it may require extra care.

Reinforced Thermosetting Resin Conduit (RTRC) or Fiberglass Conduit: Lighter than metal conduits, it can be used in a variety of indoor and outdoor applications. However, bending and cutting must be done by a professional that has specialized tools. RTRC also does not support luminaires. Compared to PVC, steel and aluminum conduits, RTRC ensures that the protected wires do not melt nor weld.

Rigid Nonmetallic Conduit (RNC): a non-metallic unthreaded smooth-walled tubing. It can be installed underground below a Class I location, for as long as the raceway is covered with not less than 2 feet of earth, concrete or asphalt.

Electrical Nonmetallic Conduit (ENC): a thin-walled corrugated tubing that can be easily bent by hand. It is moisture-resistant and flame retardant. It is used to replace EMT and other flexible metal conduits. Because of its corrugated shape, most ENCs are not threaded.

Flexible Conduits

If you have to route wires on spaces with a lot of twists and turns, flexible conduits are very helpful as you don’t have to spend extra money on bending. These are flame- and water-resistant, and anti-corrosive.

Flexible Metal Conduit (FMC): Informally called greenfield or flex, this type of conduit is made by helical coiling. It is manufactured out of a strip of self-interlocked aluminum or steel, forming a hollow tube where you can pull out your wire. It flexes freely but you can expect it to keep a bent position for years as long as you have put the necessary support around it.

Liquidtight Flexible Nonmetallic Conduit (LFNC): If you have to protect your wires against water and moisture, and where a fire is most likely to occur, LFMC is highly suggested.

Importance of Using the Right Type of Conduit

The primary use of conduits is for safety. Wires must be concealed to avoid life-threatening accidents such as short-circuits, fire and electrocution. These can also be used to group wires together, thus, isolating them from other connections, resulting in easier maintenance as you can immediately see which wires are interconnected. It also has aesthetic benefits as you won’t see any wires hanging around your place.

However, you need to keep in mind that using the right type should be on top of your priority. You need to consider a lot of factors, which include water exposure, temperature, and location. With these, you are guaranteed to enhance your property’s circuit integrity.   

Walters Wholesale Can Help

Check out what type of conduit Walters carries or call your local sales rep and we can special order the type you need.

*Restrictions may apply. Call local sales rep for more details.



Written by: Sirikit Hiyasmin Loong-Elebaran is a Filipino Freelance Writer who has 9 years of technical niche experience. She mainly provides content for electrical and IT companies. She is also the CEO and Founder of and . You can reach her at

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