Journeyman Electrician Practice Exam

The correct answer indicates that when a metal wireway contains splices and taps, the maximum percentage of area that can be filled is 75 percent. This guideline is rooted in the National Electrical Code (NEC), which establishes guidelines to ensure safe and reliable installations. The 75 percent fill limit accommodates not just the conductors but also any additional wiring space needed for splicing or tapping operations, ultimately reducing potential issues such as overheating and ensuring maintenance access.

Filling the wireway to this level allows for adequate air circulation around the wires, thereby minimizing the risk of heat buildup. It also ensures that installers have sufficient space to work within the wireway without compromising the integrity or safety of the wiring system. This practice is particularly relevant in commercial or residential applications where numerous connections or transitions may be necessary. By adhering to this maximum fill percentage, electricians help maintain compliance with safety standards and promote longevity in the electrical systems they design and implement.