Conduit bodies provide access points in electrical systems for pulling wires and performing maintenance or inspections. Their covers protect internal wiring from environmental hazards. This guide outlines the different types of conduit bodies and their classifications for use in hazardous industrial environments.
Basics Of Conduit Body Types and Their Classifications
Conduit Body Types
LB Conduit Body
An LB conduit body functions as a junction point that allows wires to make a 90-degree turn, simplifying pulling and splicing. Its L-shaped design enables this directional change. Most LB conduit bodies come with a gasket and cover to protect against water, dust, dirt, and other contaminants.
LL Conduit Body
LL conduit bodies form an L-shape, directing wires 90 degrees to the left—unlike LB conduit bodies, which turn to the back. They help reroute wiring while providing easy access for splicing, maintenance, and inspections via a removable cover.
LR Conduit Body
LR conduit bodies also create a 90-degree turn, but direct wires to the right. Like other types, they feature a removable cover for easy access, making wire pulling and splicing simple and efficient.
C Conduit Body
C conduit bodies provide a straight-through path for wiring, with no directional changes. A removable cover offers easy access for wire pulling, inspection, or replacement.
T Conduit Body
T-conduit bodies allow wires to branch off from or merge into the main run. Their T-shaped design includes a removable cover for easy access and protects wiring from water, dirt, and other contaminants.
Hazardous Classifications
Class I
Areas where flammable gases or vapors are present in concentrations high enough to pose an explosion risk.
Group A: Atmospheres containing acetylene.
Group B: Atmospheres containing gases like butadiene, ethylene oxide, acrolein, hydrogen, or other substances with similar explosion hazards (e.g., manufactured gas).
Group C: Atmospheres containing cyclopropane, ethyl ether, ethylene, or other gases or vapors with similar hazards.
Group D: Atmospheres containing acetone, alcohol, ammonia, benzene, benzol, butane, gasoline, hexane, lacquer solvents, naphtha, natural gas, propane, or other gases and vapors with similar hazards.
Class II
Areas that are hazardous due to the presence of combustible dust.
Group E: Atmospheres containing combustible metal dusts, including:
Metal dusts, regardless of resistivity
Dusts with similar hazards and resistivity less than 100 kΩ·cm
Electrically conductive dusts
Group F: Atmospheres containing combustible dusts, including:
Carbon black, charcoal, or coke dust with more than 8% total volatile content
Dusts prone to explosion, with resistivity > 100 Ω·cm and ≤ 1 × 10⁸ Ω·cm
Group G: Atmospheres containing combustible dusts that are:
Dusts with resistivity ≥ 100 kΩ·cm
Electrically non-conductive dusts