How long must a box be in a straight pull relative to the size of the largest raceway?

The correct answer is based on the National Electrical Code (NEC) requirements regarding pulling conductors through raceways. For a straight pull, the length of the box must be at least eight times the diameter of the largest raceway entering the box. This specification is intended to ensure that there is adequate space for the conductors to be pulled into the box without being damaged or excessively bending, which can lead to insulation damage or other electrical issues.

In practical terms, this means when determining the appropriate size for a pull box, electricians and designers must calculate the diameter of the largest conduit or raceway and multiply that measurement by eight to ensure compliance with these standards. This requirement promotes both safety and efficiency in electrical installations.

While other options may seem plausible, they do not align with NEC regulations for straight pulls, which is why eight times the trade size is the established standard. Understanding this helps electricians maintain safe working practices and adhere to code requirements in their installations.