What should the equipment grounding conductor in a multiconductor cable be sized according to?

The equipment grounding conductor in a multiconductor cable should be sized according to the overcurrent protective device for the feeder or branch circuit. This is based on the National Electrical Code (NEC) requirements, which specify that the grounding conductor should be sufficient to safely handle the maximum fault current that could occur in the system.

The overcurrent protective device, such as a circuit breaker or fuse, is designed to protect the conductors from excessive current that can lead to overheating, electrical fires, or equipment damage. By sizing the grounding conductor according to this device, it ensures that if a fault occurs, the grounding system can effectively conduct fault current back to the source, enabling the protective device to trip and disconnect the power, thereby maintaining safety.

The other factors mentioned, such as the size of the cable insulation, type of electrical equipment used, or the length of the cable run, do not directly dictate the appropriate size for the grounding conductor. While these factors may have implications in other areas of electrical safety and design, they are not the primary determinants for sizing the equipment grounding conductor.