How much space must be provided above non-totally enclosed switchgear from a combustible ceiling, unless a shield is provided?

The correct answer is based on safety regulations concerning the installation of non-totally enclosed switchgear in relation to combustible materials. According to electrical code requirements, specifically the National Electrical Code (NEC), there must be sufficient clearance above certain electrical equipment, such as non-totally enclosed switchgear, to prevent the risk of ignition.

Providing a 3-foot space above such switchgear helps ensure that heat generated by the electrical equipment does not inadvertently ignite combustible ceilings. This distance is a precautionary measure that recognizes the potential for heat distribution from electrical components and aims to maintain a safe installation environment.

Considering industry standards and safety practices, a shield can modify this requirement, but when no shield is present, the 3-foot clearance remains the standard. This ensures compliance with safety regulations while minimizing the risk of fire hazards.