What type of electrical service is generally required to have ground-fault protection?

Ground-fault protection is primarily required for solidly grounded wye services due to the characteristics and safety requirements of these systems. Solidly grounded wye configurations ensure that all three phases are connected to a common ground point, which helps in maintaining system stability and safety.

In the event of a ground fault, the grounding provides a low-resistance path for fault currents to flow directly to the ground. This allows protective devices to detect the fault quickly and trip the circuit, reducing the risk of electric shock and fire hazards.

While other types of services, such as open delta and ungrounded services, may have their own methods of fault detection and protection, they do not provide the same level of effective ground-fault detection inherent in solidly grounded wye configurations. This makes solidly grounded wye services the standard system which typically requires ground-fault protection measures to ensure the safety and reliability of electrical installations.