Screws or fasteners that are installed in outlet and device boxes must have what characteristic regarding their ends?

The correct answer is that screws or fasteners installed in outlet and device boxes must have blunt ends. This requirement is primarily for safety reasons. Blunt-ended screws or fasteners help to prevent accidental injury to individuals who may be working within or around the outlet or device box. Sharp ends can pose a risk of puncturing or cutting during installation or maintenance, leading to safety hazards.

Additionally, blunt screws are less likely to damage wires or other internal components of the electrical system as they are installed, which is crucial for maintaining the integrity of the electrical installation and ensuring the reliability of the devices being housed. This characteristic enhances both the safety and functionality of the electrical system, aligning with the objectives outlined in the National Electrical Code.