Minimum Working Space Width for Electrical Equipment Panels

According to National Electrical Code (NEC) 110.26(A)(2) and International Fire Code (IFC) 2021, Section 604.3, the minimum working space width for electrical equipment must be at least the width of the equipment or 30 inches, whichever is greater.

Since the equipment panel in the question is 66 inches wide, the required working space width must be at least 66 inches.

2. Why 66 Inches is the Correct Answer

The minimum clearance width must be equal to the width of the electrical equipment if the panel itself is wider than 30 inches.

This ensures safe maintenance and emergency access to electrical components.

3. Verification of Other Options

Option A (30 inches) – Incorrect, because the equipment is wider than 30 inches, requiring a larger clearance.

Option B (36 inches) – Incorrect, as this is not the requirement for a 66-inch-wide panel.

Option D (78 inches) – Incorrect, as the clearance does not need to exceed the width of the panel.

Reference Sources:

National Electrical Code (NEC) 2023 – Section 110.26(A)(2) (Working Space Width Requirements)

International Fire Code (IFC) 2021 – Section 604.3 (Electrical Equipment Clearance Requirements)

ICC Fire Inspector II Study Guide (2021)