Ceiling fan boxes designed to support more than how many pounds must have their maximum weight marked?

Ceiling fan boxes are crucial components in residential wiring, especially for fixtures that require additional support due to their weight and movement. When it comes to the safety and structural integrity of these boxes, it is essential that they are clearly marked with their maximum weight capacity when they are designed to support heavier loads.

The correct answer, 35 pounds, aligns with the National Electrical Code (NEC) requirements. These specifications ensure that any ceiling fan box intended to hold a fan or other heavy fixture can safely support the weight and that users are aware of this limit. If a fan box is marked for a weight capacity exceeding this threshold, it represents a potential safety hazard if a heavier fan is installed without proper regard for the box's limitations. By marking these boxes, it informs electricians and homeowners of the safe installation practices to follow, maintaining both compliance and safety.

The other weight options are lower than the specified requirement set by the NEC, which specifies that any box supporting more than 35 pounds must be marked. This helps prevent installation errors that could lead to structural failures, possible injuries, or damages. Having this clarity ensures that anyone involved in the installation or maintenance of ceiling fans can make informed decisions regarding their setup.