6 Types of Electrical Conduits
An electrical conduit (EC) is a piping system that is used to carry electrical wiring for either power or communication. These piping systems are commonly referred to as raceways. The ECs are solid and they are used to both house and protect electrical cables and wiring. EC’s may be made from a variety of metals, plastics, and fibers, as well as a variety of different sizes. Some of these varieties are available in flexible forms for your special project needs and run in 10-foot increments. Here is a list of your most common ECs.
Type 1 - Rigid Non-Metallic Conduit (PVC)
PVC is made from a combination of plastic and vinyl. PVC pipes can be installed above ground, underground, or encased in cement. PVCs are the most commonly used underground. These pipes are lightweight, flexible, impact-resistant, non-conductive, ultraviolet-resistant, and corrosion-resistant. They are popular because they have watertight joints and low installation costs. They are not interchangeable with other ECs.
Type 2 - Rigid Metal Conduit (RMC) / Rigid Steel Conduit (RSC)
RVCs and RSCs are your heaviest and thickest option, typically made of coated steel, stainless steel, red brass, or aluminum. These pipes can be installed above ground or underground. They are similar in appearance to metal water pipes and are threaded at both ends. The threads on the uncoupled end of the pipes are covered by industry color-coded thread protectors, which protect the threads, keeping them clean and sharp. Although RMCs and RSDs are generally corrosive resistant, a layer of PVC or zinc (see GRC) can be added in areas that are wet or highly corrosive. If you opt for an organic coating you check for heat restrictions. These types are interchangeable with GRCs.
Type 3 - Intermediate Metal Conduit (IMC)
If you opt for an organic coating, you need to check for heat restrictions. They are interchangeable with GRCs.
Type 4 - Galvanized Rigid Conduit (GRC)
GRCs are created by taking one of your above RMC, RSD, or IMC and galvanizing it via hot dipping it in zinc. The zinc coating provides extra coating in areas that are wet or highly corrosive. GRCs are interchangeable with most RMC, RSD, and IMC to use when only an area of your piping is in need of additional protection. PVC coating can be added on top of GRC coating for ECs that will be exposed to chemicals and other highly abrasive materials.
Type 5 - Electrical Metal Tubing (EMT)
EMTs are not interchangeable with other ECs. EMTs are generally less expensive and lighter than GRCs.
Type 6 - Flexible Metal Conduit (FMC)
This is your best option for areas that need to sustain large amounts of movement and vibration. They are found in stainless steel, galvanized steel, or aluminum. They can be waterproof if needed and are installed above ground. The appearance is similar to that of metallic armored cable. They are often used when wiring motors and are not interchangeable with other ECs.