Which fitting is required for raceways crossing structural joints to accommodate thermal expansion?

The requirement for fittings when raceways cross structural joints is fundamentally tied to the need to accommodate thermal expansion and movement. In construction, as temperatures change, materials expand or contract. Therefore, fittings that can absorb this movement are crucial to maintaining the integrity and functionality of electrical systems.

Expansion/deflection fittings are specifically designed to allow for this movement. They can absorb the thermal expansion that occurs in raceways, preventing undue stress on the joints and connections as the materials contract and expand with temperature changes. These fittings provide the necessary flexibility, ensuring that the raceway maintains its alignment and does not create tight bends or undue pressure on the cables inside, which can lead to damage or failure of the system.

On the other hand, elbow fittings, coupling fittings, and connector fittings serve different purposes within wiring systems. Elbow fittings change the direction of the raceway but do not provide flexibility for expansion. Coupling fittings join two lengths of raceway together, but do not accommodate movement. Connector fittings attach raceways to other equipment or fixtures, and while essential for securing connections, they also lack the ability to handle expansion and deflection. Using the proper fitting, like the expansion/deflection fitting, ensures that the electrical system remains functional and safe amidst temperature fluctuations