What is the minimum size EGC permitted for a circuit with the smallest conductors and the largest permitted DETD fuses for a 1 hp motor?

To determine the minimum size Equipment Grounding Conductor (EGC) required for a circuit with the smallest conductors and the largest permitted DETD (Dual Element Time Delay) fuses for a 1 horsepower (hp) motor, it is essential to refer to the National Electrical Code (NEC) guidelines.

For a 1 hp motor, commonly used conductors are typically 14 AWG or larger, and the NEC specifies that the grounding conductor must be sized appropriately based on the ampacity of the conductors, continuity of the ground path, and other safety factors. In the case of a circuit with the smallest conductors at 14 AWG, the NEC does allow for a minimum equipment grounding conductor size of 14 AWG in specific situations.

Considering the typical relationship between the size of the circuit conductors and the associated EGC, using a 14 AWG EGC is sufficient for smaller conductor sizes when using appropriate fuse ratings for the protective devices. This aligns with the NEC requirements for residential and commercial installations where EGC sizes must be calculated based on the size of the branch circuit conductors, motor size, and overcurrent protection provided by fuses.

In summary, when using the smallest conductors (14 AWG