Which of the following combinations correctly lists how screws may be chosen for attaching receptacles or covers to outlet boxes?

• A. Drywall screws
• B. In accordance with the manufacturer's instructions
• C. Machine screws matching the thread gauge or size integral to the box
• D. Either B or C

Answer: (D)

Attaching receptacles or covers to outlet boxes must use fasteners that the equipment is designed to accept. The screws should be either specified by the manufacturer or be machine screws that match the box’s threaded holes. Drywall screws aren’t appropriate here because they may not fit the box threads and can damage the box or device, potentially affecting listing and safety. So the proper approach is to follow the manufacturer’s instructions or use the machine screws that match the box’s thread size.