What percentage of the area can be filled by conductors, including splices and taps, in a wireway?

The correct answer is based on the National Electrical Code (NEC) guidelines regarding wireways. In general, the NEC allows for a maximum fill of 75% of the available space in a wireway by conductors. This guideline is critical for ensuring safe heat dissipation and minimizing the risk of overheating, as an overcrowded wireway can lead to increased resistance and potential failure of the conductors.

By adhering to this 75% fill limit, electricians ensure that there is adequate space for the conductors to operate safely without interference, and it allows for additional components like splices and taps to be safely included without exceeding the space limitations. Knowing this percentage helps in the proper planning and execution of electrical installations, ensuring that they comply with safety standards and regulations.