Separate Ground Requirement for Motors

According to the National Electrical Code (NEC), a separate equipment grounding conductor (EGC) is required for all motors rated at 150 volts or more between phases and 100 volts or more to ground.

Conduit as Ground

While using the conduit as a ground is acceptable in certain situations, it is not recommended for motors. This is because conduit is not a reliable path for grounding due to possible corrosion, poor connections, or damage.

Wiring Parameters for Motors Hot Conductors

The number of hot conductors depends on the motor's poles and phases. A single-phase motor requires one hot conductor, while a three-phase motor requires three.

Neutral Conductor

A neutral conductor is required for all single-phase motors and for three-phase motors with a grounded neutral.

Separate Ground Conductor

An EGC is required for all motors rated at 150 volts or more between phases and 100 volts or more to ground.

Conduit Grounding

Conduit can only be used as a ground path if it meets the following conditions: It is rigid metal conduit (RMC) or intermediate metal conduit (IMC). It is properly connected with grounding bushings and fittings.* It is continuous from the motor to the electrical panel.

Conclusion

It is generally not recommended to use the conduit as a ground for motors. A separate EGC should be provided to ensure a reliable and safe grounding path. The wiring parameters for motors must be followed to meet code requirements and prevent electrical hazards. Flag for review