The length of a straight pull for multiple raceways must be what in relation to the trade size of the largest single raceway?

The proper relationship for the length of a straight pull involving multiple raceways is that it must be at least eight times the trade size of the largest single raceway. This requirement is outlined in the National Electrical Code (NEC), which specifies that when making a straight pull, the overall length of the pull should allow adequate space for each conductor to be pulled through without undue stress or potential damage.

In this context, the trade size refers to the diameter of the largest conduit being used in the pull. The reason for the eight times multiplier is to ensure enough clearance and to facilitate smoother pulling of the conductors. If the pull is done too short, it can lead to excess strain on the conductors as they navigate through bends or other resistances, increasing the risk of insulation damage and electrical failures.

Understanding this relationship is crucial in ensuring safe and compliant electrical installations. The other options suggest a length that would be insufficient, which could potentially result in greater difficulty and risks during the pulling process, creating a scenario where conductor integrity might be compromised.