NEC Commercial Electrical Practice Test

How far must thermal insulation be kept from a lighting fixture or ballast?

1. 1 inch

2. 2 inches

3. 3 inches

4. 4 inches

The correct answer is: 3 inches

Thermal insulation must be kept a minimum distance of 3 inches from a lighting fixture or ballast to prevent overheating and potential fire hazards. This clearance is important because lighting fixtures, especially those that generate heat, can reach high temperatures during operation. If insulation is placed too close, it can become a fire risk, igniting or degrading the integrity of the materials. Maintaining this 3-inch space allows for proper heat dissipation and ensures that the lighting apparatus operates safely without compromising the effectiveness and longevity of both the fixtures and the insulation materials. Additionally, adhering to these standards is not just a best practice but is also in alignment with safety codes and regulations outlined in the National Electrical Code (NEC). This knowledge is crucial for electricians and installers to ensure compliance and safety in residential and commercial setups.