Which requirement must be met for a box that contains a splice?

For a box that contains a splice, it is essential that the box is accessible and has adequate volume for the splices. This requirement is critical for several reasons.

First, accessibility ensures that the splices can be inspected, maintained, or repaired without requiring significant effort or disruption to the building structure. When splices are accessible, electricians can easily access them for troubleshooting or future modifications, promoting safety and functionality in the electrical system.

Additionally, the volume of the box is crucial because it must accommodate the wires, any connectors or splices, and the necessary fill calculations according to the NEC. The National Electrical Code specifies the minimum box sizes based on the number of conductors and the types of connections to ensure that there is enough space to prevent overheating and to allow for safe wiring practices. An insufficient volume can lead to overheating, wire insulation breakdown, and potentially hazardous situations.

In contrast, locating a box in a non-accessible area, requiring extra support brackets, or allowing for any volume without regard to the number of splices would compromise safety and code compliance, which is why these options do not meet the requirements specified in the NEC.