Electrical Conduit & Fittings Guide

EMT (Electrical Metallic Tubing) is a lightweight, thin-walled galvanized steel conduit used to protect and route electrical wiring in buildings. It is the most common type of metallic conduit used in commercial and light industrial electrical work. EMT uses set-screw or compression fittings (it cannot be threaded) and is suitable for exposed, concealed, and some outdoor installations.

East Electrical's galvanized electrical metallic tubing (EMT) is manufactured from high-strength steel. The interior and exterior surfaces are coated with zinc in a hot dip galvanizing process for protection against corrosion.

EMT conduit is available in ten trade sizes: 1/2", 3/4", 1", 1-1/4", 1-1/2", 2", 2-1/2", 3", 3-1/2", and 4". The trade size approximates the inside diameter; actual outside diameters are slightly larger and standardized so fittings from different manufacturers are interchangeable.

Rigid conduit, also called GRC (Galvanized Rigid Conduit) or RMC (Rigid Metal Conduit), is a heavy-wall threaded steel conduit providing maximum physical protection. It is used in demanding installations: outdoor exposed runs, direct burial, encasement in concrete, and hazardous locations. GRC offers superior crush and impact resistance compared to EMT.

The outside diameter (OD) of 2-inch trade size rigid conduit (GRC/RMC) is 2.375 inches (60.3 mm). This standardized dimension ensures 2-inch fittings from any manufacturer will fit correctly. The 2-inch trade size refers to the approximate inside diameter.

Part number formats differ by market. In the US, rigid conduit part numbers follow the format GRC50, GRC75, GRC100, GRC125, GRC150, GRC200, etc. — the numeric suffix is the trade size in hundredths of an inch (GRC50 = 1/2", GRC75 = 3/4", GRC100 = 1"). In Canada, part numbers follow the format 012R, 034R, 100R, 114R, 112R, 200R, etc. — the numeric prefix represents the trade size.

EMT has thinner walls, weighs less, and uses set-screw or compression fittings — ideal for most interior commercial applications. Rigid conduit (GRC) has much thicker walls, can be threaded, and is suited for outdoor runs, direct burial, concrete encasement, and locations requiring heavy physical protection. EMT cannot be threaded; rigid conduit cannot be easily bent in the field.

A conduit body (outlet body) is a fitting installed in a conduit run that provides access for pulling wire, making splices, or changing direction. Types include: LB, LL, LR (90-degree turns), T (T-junction with three openings), and C (straight through for wire pulling). All have removable covers for field access.

An LB conduit body is an L-shaped electrical fitting that provides a 90-degree change in direction for a conduit run. The 'B' indicates the second conduit port exits the Back of the body. The removable cover allows wire pulling or future access without disassembling the conduit.

LB, LL, and LR are all L-shaped conduit bodies that provide a 90-degree turn. The letter after L indicates where the second conduit port (opening) exits the body: B means the port exits the Back, L means it exits the Left side, and R means it exits the Right side. The cover is always in the same accessible position on all three types. The correct choice depends on the direction the conduit run must travel.

Raintight conduit fittings use a compression ring and integral seal to prevent water ingress at conduit connections. They are used in wet locations exposed to rainfall. Raintight compression connectors and couplings are commonly used with EMT in outdoor installations, replacing standard set-screw fittings.

Common electrical box sizes include: 2x4" single-gang device boxes, standard 4" square boxes, 4-11/16" square boxes offering greater wire capacity, octagon boxes for ceiling fixtures, and shallow round pancake boxes. The 4-11/16" square box is popular for junction applications or runs with heavy wire fill.

A pancake box is a very shallow round electrical box, typically 1/2" deep, designed for ceiling or wall mounting where depth is limited. It is commonly used for light fixtures where the box mounts directly against a ceiling joist. Pancake boxes are also called shallow boxes or ceiling fan boxes.

A 4-11/16" square electrical box measures 4.6875" on each side of its square footprint. Depth options typically range from 1-1/2" to 2-1/8". These boxes have a larger cubic inch capacity than standard 4" boxes, making them suitable for multiple devices, conduit entries, or runs with many conductors.

East Electrical Supply is a North American distributor of electrical conduit, fittings, and related products, founded in 2012. Headquartered in Mississauga, Ontario, Canada, we serve both Canadian and US markets through regional warehouse partners in Alabama, Georgia, Texas, and Pennsylvania. Contact us at +1 855 785-8275.

Flexible conduit is a spiral-wound interlocked conduit that bends freely, used for motor connections, vibrating equipment, and anywhere a rigid conduit run cannot be routed. East Electrical Supply's US flexible conduit range includes: Flexible Steel Conduit (RWS) for dry indoor use, Liquidtight Conduit (LTMC) for wet and outdoor locations, Flexible Aluminum Conduit (RWA) for corrosive environments, and Top-Flex 1 Tubing (HF) for specialized applications. Liquidtight connectors are required where LTMC or RWA terminates into a box in a wet location.