An electrical conduit is a plastic or metal pipe that serves as a housing for electrical wires. Conduits play a crucial role in various applications, especially in exposed locations such as exterior wall surfaces. They offer protection for cables and are essential in unfinished areas like attics, crawlspaces, basements, and even surface-mounted outdoor installations. At first glance, electrical conduit may appear similar to armored cable wiring. Like conduit, armored cables encapsulate insulated and separate wires, making them suitable for use in exposed environments.

Conduit, as a term, is commonly used to refer to a system that contains a series of electrical conductors. The specific reasons for installing conduit systems are as follows:

• Facilitating the creation of taps and splices in conductors by providing cavities.

• Serving as pull outlets for the installed conductors.

• Ensuring a robust connection between different conduit sections.

• Enabling the establishment of taps, particularly for branch conduit runs.

• Offering access for conductors in the context of future system and maintenance requirements.

• Allowing the formation of 90-degree bends for conduit runs.

• Serving as mounting outlets for lighting fixtures and wiring devices.

These characteristics and functions make electrical conduit an indispensable component in various electrical installations.

Different Varieties of Electrical Conduits

Conduit systems are primarily categorized based on the materials used to provide mechanical rigidity, tubing characteristics, and wall thickness. The selection of materials takes into account considerations like corrosion resistance and cost-effectiveness, especially in applications that require prior approval for wiring equipment in hazardous areas. Various conduit types find common use in residential and commercial lighting installations.

Electrical Metallic Tubing (EMT)

Electrical Metallic Tubing (EMT) represents a widely used example of a rigid conduit. Typically crafted from galvanized steel, EMT can also be made from aluminum. It’s often referred to as “thin-wall” conduit due to its relatively thinner and lightweight construction compared to RMC. EMT may be rigid, but it possesses the flexibility to be bent using a simple tool known as a conduit bender.

EMT installation involves the use of fittings and couplings, which are securely fastened with compression-type connectors or setscrews. Unlike IMC or RMC, the tubing itself is not threaded. Standard sizes for EMT typically range from 1 inch to 1.5 inches. EMT is commonly employed for exposed indoor wiring and is frequently found in light commercial and residential construction projects. As a result, it’s crucial to pair it with specialized watertight fittings for optimal performance and safety.

Rigid Metal Conduit (RMC)

Rigid Metal Conduit (RMC) is a robust galvanized steel conduit that requires threaded fittings for installation. It is commonly employed outdoors to provide enhanced protection against damage. Furthermore, RMC plays a pivotal role in offering structural support for electrical panels, cables, and various equipment. RMC is typically sold in lengths ranging from 10 to 20 feet, with threads at both ends.

RMC is often considered one of the more expensive options for electrical wiring. However, it excels in providing additional strength and durability, making it a valuable choice for applications where these characteristics are paramount.

Intermediate Metal Conduit (IMC)

Intermediate Metal Conduit (IMC) represents a lighter-weight and thinner counterpart to RMC. Despite its lighter construction, IMC is approved for use in similar applications as RMC. IMC is frequently preferred in construction due to its ease of handling and maneuvering. It delivers the same level of protection as RMC while serving as a more cost-effective option for projects where budget constraints are a concern.

Flexible Metal Conduit (FMC)

Flexible Metal Conduit (FMC), also known as “Greenfield” in reference to its inventor, features a spiral design that imparts exceptional flexibility. This flexibility enables FMC to navigate through walls and various structures with ease. Standard FMC is typically utilized in dry indoor locations and is best suited for shorter cable runs.

Additionally, FMC serves as an excellent alternative in situations that require close quarters and tighter bends, where traditional conduits may be challenging to manipulate. Common applications for basic flexible conduit installations include lighting systems, attic vents, and water heaters.

Liquid-Tight Flexible Metal Conduit (LFMC)

Liquid-Tight Flexible Metal Conduit, often abbreviated as LFMC, is a specialized form of flexible metal conduit that requires sealed fittings to ensure water resistance. Its design incorporates a plastic coating, making it entirely watertight. LFMC is frequently employed with outdoor equipment such as air conditioner units.

Electrical Non-Metallic Tubing (ENT)

Electrical Non-Metallic Tubing, referred to as ENT, is a flexible, corrugated plastic tubing that is typically installed with either glued plastic fittings or snap-lock connectors. It is versatile in its application, suitable not only for metal-frame walls and standard woods but also for installation within concrete block structures, where it can be initially encased in concrete. ENT is colloquially known as a “smurfing tube” due to its distinctive blue color.

Rigid PVC Conduit

Rigid PVC Conduit, made of rigid polyvinyl chloride, closely resembles plastic plumbing pipes and is well-suited for use in corrosive environments. Installation involves plastic fittings that are securely glued in place, and the conduit can be bent after heating with a portable heater box. The fusion of fittings and conduit tubing results in a watertight assembly. PVC conduit is particularly suitable for quick burial in the ground and a variety of other applications.

Key Advantages of Rigid PVC Conduit:

• Available in multiple wall thickness options.

• Generally more cost-effective compared to alternative choices.

• Suitable for underground and concrete installations.

Despite its many advantages, it’s important to note that Rigid PVC should not be used in areas with prolonged direct sunlight exposure, as sunlight can degrade the material over time. Nevertheless, overall, Rigid PVC remains a compelling option for various applications.