A conduit system is typically classified based on the materials utilized. These materials are related to aspects such as mechanical inertia, tubing characteristics, and wall thickness. When determining the appropriate material for a conduit system, factors like corrosion resistance and automatic protection are taken into consideration.
For safety reasons, specific wiring equipment guidelines must be strictly followed. Here are the types of conduits used in residential and commercial lighting.
#1. Electrical Metallic Tubing (EMT):
Electrical Metallic Tubing (EMT) is a common form of non-flexible conduit, typically made from galvanized steel or aluminum. This tubing is often regardedas a thin-walled conduit since it is both thinner and lighter in comparison to RMC.
EMT is installed using fittings and couplings that are safeguarded by compression-type fasteners or set-screws. Unlike IMC or RMC, the tubing itself is not threaded. Standard EMT sizes rangefrom 1 to 1.5 inches. It is commonly employed for exposed indoor wiring, especially in light commercial or residential construction. Consequently, assembling it with special water-tight fittings is of equal significance.
#2. Rigid Metal Conduit (RMC):
RMC, which stands for Rigid Metal Conduit Heavyweight Galvanized Steel, is installed with threaded fittings. It is predominantly used outdoors to offer protection against damage and also provides essential structural support for electrical panels, cables, and other equipment. RMC is available in lengths of 10 to 20 feet and has threads on bothends. This conduit is among the costlier options for electrical wiring in the market. However, it provides enhanced strength and durability, which is a significant advantage.
#3.Intermediate Metal Conduit (IMC):
As the name implies, the wall thickness of thisconduit is thinner than that of RMC but thicker than EMT. Similarly, its weightlies between that of RMC and EMT. This metal conductor can be threaded or unthreaded and can be used with clamp-type fittings. IMCs are usually made of steel and may also have a coating.
#4. Flexible Metal Conduit (FMC):
This conduit is also known as “greenfield,” named after its inventor. It has a spiral structure that imparts extreme flexibility, allowing it to pass through walls and other structures. Standard FMCs are typically used in dry indoor locations and are usually for short distances. It’s an excellent choice for areas with limited space and sharp turns.
#5. Liquid-tight Flexible Metal (LFMC):
LFMC, or liquid-tight flexible metal conduit, is a particular type of flexible metal conduit that requires a seal fitting and features a plastic coating. The components of the LFMC are water-resistant.This metal electrical conduit is used for equipment with an outdoor unit.
#6.Electrical Non-Metallic Tubing-(ENT):
ENT is a thin-walled, flexible corrugated conduit that can be bent without the need for a special tool, but it should notbe twisted. It is easy to install as it can be maneuvered around obstacles without cutting or welding.
#7. Rigid PVC Conduit:
Rigid polyvinyl chloride (PVC) resembles plasticpipes and is installed with plastic fittings. It can be bent after heating in aportable heater box. PVC is suitable for direct burial in the ground in many applications and is also permitted in corrosive environments.
