Luminaires containing a metal halide lamp must have what kind of safeguard?

Luminaires that use metal halide lamps require a containment barrier to ensure safety in the event of a lamp failure. Metal halide lamps operate under high pressure, and if a lamp ruptures, it can result in hazardous situations, including the projection of hot glass or explosion of gases. The containment barrier is designed to prevent such debris from escaping into the surrounding area, thereby protecting people and property from potential injuries or damages. This safety feature is a critical requirement in adhering to the National Electrical Code, which emphasizes the importance of mitigating risks associated with high-intensity discharge lighting applications.

Other options, such as smoke detectors, heat resistors, or automatic shut-off switches, do not directly address the specific risks associated with the failure of metal halide lamps and are therefore not mandated safeguards in this context. While they may enhance overall safety in electrical installations, they do not serve the primary function of containing the hazardous effects of a lamp failure.