What must a raised plaster cover, often called a mud ring, be marked with to increase conductor capacity in an outlet box?

A raised plaster cover, or mud ring, is typically marked with cubic-inch volume to provide important information regarding the conductor capacity of an outlet box. In residential wiring, every junction box must have ample space for any conductors, connectors, and devices to ensure safety and compliance with electrical codes.

The marking of cubic-inch volume indicates how much conductor fill the box can accommodate, which is crucial for preventing overheating and ensuring that the wiring system is safe and effective. Proper conductor capacity helps to prevent issues such as circuit overloads or short circuits that can occur if too many wires are crammed into a box without adequate space. This also ensures that the installation meets the National Electrical Code (NEC) requirements, which aim to minimize fire hazards and enhance electrical safety.

Other options, such as voltage rating, manufacturer’s date, and wire gauge, do not provide sufficient information regarding the physical capacity of the outlet box to hold conductors safely. Thus, the cubic-inch volume marking is essential for maintaining the integrity of the electrical system.