For a raceway with 30 current-carrying conductors, to what percent of single conductor ampacity should the ampacity of each conductor be reduced?

In situations where you have multiple current-carrying conductors in a raceway, the National Electrical Code (NEC) specifies that the ampacity of each conductor must be adjusted to prevent overheating and to ensure safe operation. For a raceway with 30 current-carrying conductors, the ampacity of each conductor is reduced to 60% of its original single-conductor rating.

This reduction is based on the principle that when many conductors are bundled together, they generate more heat due to the cumulative heat from each conductor. The NEC recognizes this heating effect and requires that ampacity adjustments be made according to the number of conductors to prevent potential overloads. Therefore, for 30 conductors, the allowed ampacity is set at 60% to maintain safety and reliability in electrical systems.