What is the maximum number of 3 AWG THWN/THHN conductors that can be installed in a trade size 3 EMT?

To determine the maximum number of 3 AWG THWN/THHN conductors that can be installed in a trade size 3 EMT (Electrical Metallic Tubing), it's essential to reference the National Electrical Code (NEC) and its accompanying tables that define fill capacity for raceways.

The NEC provides specific tables that outline the maximum number of conductors permitted in a given raceway size based on the conductor's cross-sectional area. For THHN conductors, table 1 in Chapter 9 provides the necessary details to calculate the allowable fill.

In the case of 3 AWG conductors, each conductor has a specific fill volume (cross-sectional area) that must be taken into account. For trade size 3 EMT, which has a certain internal diameter and volume, the total volume available for the conductors is finite.

The maximum allowable fill is typically calculated based on the 40% fill rule for conductors in raceways, which stipulates that the space occupied by the conductors must not exceed 40% of the total area of the raceway. Upon performing the calculations, along with considering derating factors and ensuring compliance with the NEC, it is found that the total number of 3 AWG THWN/TH