Expansion fittings must be provided in raceways to compensate for which of the following?

Expansion fittings are specifically designed to accommodate the changes in length of raceways due to thermal expansion. As temperature changes, materials such as metal and plastic expand and contract. If raceways are rigidly secured without any means to relieve stress from thermal expansion, it could lead to damage, warping of the raceway, or even potential failures of the associated electrical systems.

The use of expansion fittings allows for this movement, ensuring that the integrity of the raceway system is maintained and functioning safely. Although contraction is a related process that occurs as temperatures decrease, the focus here is on the expansion aspect, which is crucial for safe installation and operation.

Raceways must be able to handle these fluctuations in size to prevent physical damage and maintain the performance and security of the electrical system housed within. The mention of deflection is less relevant in this context, as it refers more to bending or shifting rather than thermal response. Therefore, the correct emphasis on thermal expansion establishes the need for such fittings in wiring methods.