Conduits and Their Uses
Electrical conduits are essential components in any building's electrical system, serving the crucial function of protecting and routing electrical wiring. There are many types of conduits available, each with its own characteristics and applications. Let’s examine the five most common conduits that the typical homeowner is likely to see in their home.
1. PVC Conduit
Polyvinyl chloride (PVC) conduit is perhaps the most widely used type of conduit in residential and light commercial applications. It's known for its affordability, ease of installation, and resistance to corrosion and chemicals. PVC conduit comes in sizes 1/2” up to 6'“ and is usually sold in ten foot lengths. There is Schedule 40 and Schedule 80 type conduits, with the difference being that Schedule 80 is meant to be installed in environments where physical damage is more likely (from lawnmowers, kids hitting things with rocks, etc.). PVC is probably what you see emerging from the ground if your service is buried. PVC is meant for both wet and corrosive locations.
2. RMC Conduit
Rigid metal conduit (RMC) is a heavy-duty conduit made of galvanized steel or aluminum. It provides the highest level of protection for electrical wiring and is often used in industrial and commercial settings where durability and mechanical protection are crucial. RMC conduits require threaded fittings and are generally more difficult to install than other types due to their weight and rigidity. The only time a typical homeowner will see RMC is when their service is overhead and is attached to the mast itself. In that case, it is state law in North Dakota that that conduit must be RMC to be able to hold that weight. RMC can be used as a grounding path, but given its rarity in residential applications, and its use as service equipment when it is, this isn’t often a useful feature.
3. EMT Conduit
Electrical metallic tubing (EMT) is a lightweight conduit made of thin-walled galvanized steel or aluminum. It's easy to bend and cut, making it popular for exposed indoor and outdoor wiring applications where aesthetics are a concern. EMT conduits are economical and quick to install, though they provide less mechanical protection compared to RMC. This is not an issue for the typical homeowner, as RMC is made with the assumption that it will be harshly treated, whereas EMT is meant to stand the occasional knock. If you’re feeling very artistic, EMT can be ordered in almost any color, and holds paint well if you want a specific color to match your house. Again EMT can also be used as a grounding path, potentially eliminating a wire and therefore potentially reducing conduit size.
4. ENT Conduit
Electrical non-metallic tubing (ENT) is a flexible plastic conduit that's commonly used in residential construction. The field slang for ENT is “smurftube” due to it often being blue. It's made of flame-retardant PVC and is easy to install without requiring specialized tools, since lot of the fittings are simply push-to-connect. ENT conduits are often used for concealed wiring in walls and ceilings where flexibility and ease of installation are advantageous. They are much more tolerant of future expansion and changes, and in certain situations can be a cost-saving option.
5. FMC Conduit
Flexible metal conduit (FMC) is a flexible tubing made of galvanized steel, stainless steel, or aluminum. It provides mechanical protection for wires while allowing for flexibility and ease of installation. FMC conduits are often used in situations where EMT or RMC may be difficult to install due to bends or twists in the wiring path. Think of it as a compromise between the ease-of-install and flexibility of ENT and the durability and protection of EMT. FMC can also be used as a grounding path with certain limitations on its length and circuit ampacity if it’s going to be used for that.
Conclusion
Selecting the appropriate conduit depends on several factors including the environment, mechanical protection requirements, installation ease, and budget. For example, PVC conduits are great for residential applications where cost and moisture resistance are key, while RMC is ideal for industrial environments needing maximum protection.
Understanding these different types of electrical conduits will help you make informed decisions when planning and installing electrical systems in various settings. On that topic, there are other types of conduits the aren’t touched on, including LFMC, RTRC, IMC, and FMT just to name a few. Choosing the right conduit ensures safety, longevity, and efficiency in electrical installations. Prosperity Electric provides electrical service in Grand Forks and the surrounding area, and we’re ready to serve you.
