When calculating wire fill, what is the percentage allowed for two wires according to the National Electrical Code?

The correct percentage allowed for two wires when calculating wire fill according to the National Electrical Code (NEC) is 31%. This figure is derived from NEC guidelines, which provide standards for the maximum number of conductors that can be placed in a given conduit or raceway. The 31% fill rate is intended to ensure that there is sufficient space for heat dissipation and to prevent overheating that can lead to electrical hazards.

When calculating conduit fill, it’s important to follow these guidelines to ensure safety and compliance with electrical codes. These values help to maintain proper functioning of electrical installations while managing the risks associated with overcrowding conductors in conduits.