What is the purpose of an "expansion fitting" in raceways?

An expansion fitting is specifically designed to accommodate movement resulting from thermal expansion or contraction within raceways. When electrical conductors run through raceways, temperature changes can cause materials to expand or contract, which might lead to stress on connections and damage over time if not properly managed. By incorporating expansion fittings into the system, the potential for tension in the conductors and raceway is alleviated. This ensures the integrity of the installation is maintained, minimizing the risk of electrical faults or raceway failure due to thermal influences.

The other options do not accurately describe the primary function of an expansion fitting. Increasing electrical capacity typically involves the use of larger raceways or conductors, while securing raceways to structures is achieved through mounting hardware. Connecting raceways to non-electrical systems involves different fittings that do not account for the specific needs related to thermal movement.