What percent of a metal wireway cross section may be occupied by splices, taps, and conductors at any point?

In metal wireways, the occupancy of the cross section is critical to ensure safe and efficient operation. The correct answer indicates that a maximum of 75% of a metal wireway's cross section can be occupied by splices, taps, and conductors at any point. This figure is established to prevent overheating, promote proper airflow, and reduce the risk of electrical faults.

Maintaining this maximum occupancy is essential under the National Electrical Code (NEC) guidelines, which aim to ensure that conductors have enough space for heat dissipation and that there's room for installation and maintenance. By allowing 75% occupancy, it provides a balance between efficiency and safety, ensuring that the wireway can still accommodate necessary electrical connections without compromising performance.

While lower percentages are also provided in the options, none of them meet the requirements set by the NEC for today’s standards, which specify this 75% capacity limit. This ensures that installation practices can enhance performance while mitigating risks associated with electrical systems.