ANSI C80.1-2020: Electric Rigid Steel Conduit

Electrical conduits in an electrical system that adhere to ANSI C80.1-2020.

An electrical conduit is a tube in which electrical wires are housed for a variety of building or structural applications. From data centers and underground subways to ports and bridges, electrical conduit is an integral part of the modern world, and it protects both wires and any individuals who may come into close proximity to them. ANSI C80.1-2020: Electric Rigid Steel Conduit covers the requirements for an electrical rigid steel conduit for use as a raceway for wires or cables of an electrical system.

What Is ANSI C80.1?

ANSI C80.1-2020 establishes the requirements for electrical rigid steel conduit for use as a raceway for wires or cables of an electrical system. Raceway systems (conduit, fittings, and enclosures) provide mechanical protection for circuit conductors and carry potentially dangerous fault currents. This American National Standard specifies that the finished conduit should be produced in standard 10 ft (3.05 m) lengths, threaded on each end with one coupling attached. It also mentions that the production of conduit lengths shorter or longer should be allowed, whether threaded or unthreaded and with or without couplings.

Electrical rigid metal conduit in the scope of ANSI C80.1-2020 is protected on the exterior surface with a metallic zinc coating or alternate corrosion protection coating and on the interior surface with zinc or organic coating. ANSI C80.1-2020 additionally covers conduit couplings, elbows, and nipples and other identified fittings—all of which should provide for the electrical continuity required of an equipment grounding conductor.

What Is the Difference between Metallic Rigid and Non-Rigid Conduit?

Conduit assures electrical wires do not suffer damage due to an accident or environmental conditions, such as moisture or extreme cold or heat. It makes it easy to pull wires through finished walls and allows for convenient changes if wiring needs change. The two main types of metallic conduit and raceway are flexible and rigid:

Flexible metal conduit (FMC) has a spiral construction that makes it flexible, so it can snake through walls and other structures. It allows for bends and twists without using extra hardware as well as for turns at corners without using elbow joints. FMC is made by coiling self-interlocked steel or aluminum strips to form a hollow tube for electrical cables. It is used in dry indoor locations, often for short runs between a wall box and a motor or fixed appliance, such as a garbage disposer. Liquid-tight flexible metal conduit (LFMC) is a special type of flexible metal conduit with sealed fittings and plastic coating to make it watertight and corrosion-resistant. Therefore, it can be used in wet areas, unlike FMC, which is only suitable for dry locations. LFMC is a common choice for outdoor environments such as air conditioning units.

Alternatively, rigid metal conduit (RMC) is a thick-walled threaded tubing, usually made of coated steel, stainless steel, galvanized steel, or aluminum. Screwing connectors connect the conduit to the main tubes. A rigid metal conduit is an excellent choice for protecting against impacts and severe damage due to its strong construction. Its thick walls protect sensitive equipment from electromagnetic interference and is used in a variety of environments, such as where chemical fumes are found, underwater, and oil refineries.

Types of Electrical Conduit

Depending on the needs of the installation environment, there are many different types of conduits available, such as:

  • Electrical metallic tubing (EMT) is lightweight and easy to install. It has much thinner walls than RMC and is also unthreaded. As a result, it is a popular option for use in commercial buildings.
  • Intermediate metallic conduit (IMC) has a thicker, galvanized wall, making it suitable for outdoor applications. It is a thinner, lighter version of rigid metal conduit (RMC) but can still be used in similar applications to RMC. 
  • Galvanized rigid conduit (GRC) is galvanized steel tubing, with a tubing wall that is thick enough to allow it to be threaded. It is thickest and offers the most protection.
  • Polyvinyl chloride (PVC) is coated steel conduit is used for highly corrosive environments. Because the conduit tubing and plastic fittings are glued together, the conduit assemblies can be watertight, making PVC suitable for direct burial in the ground for many applications.

ANSI C80.1-2020: Electric Rigid Steel Conduit is available on the ANSI Webstore.

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