In a string of 2' x 4' lay-in fluorescent luminaires using the looping wiring method, what is the maximum distance permitted between two supports?

The maximum distance permitted between two supports for 2' x 4' lay-in fluorescent luminaires using the looping wiring method is 3 feet. This specification is based on the need to ensure that the fixtures are securely supported and do not sag or become loose over time, which could pose safety issues or lead to operational problems.

In commercial and industrial settings, luminaires must be adequately supported to maintain structural integrity and function properly. The 3-foot maximum distance is designed to provide sufficient stability for the fixtures, particularly when considering factors such as vibrations or movements within the space they are installed.

This distance aligns with the National Electrical Code (NEC) requirements, which stipulate the spacing for supporting fixtures to promote safety and reliability. By adhering to this standard, electrical contractors can ensure compliance with regulations and enhance the lifespan and performance of the lighting system.