Parts of an electrical system that should be connected to earth ground include _______.

In electrical systems, grounding is a crucial safety measure that helps prevent electrical shocks, protects equipment, and ensures the safe operation of electrical installations. Each part of the electrical system listed plays a significant role in enhancing safety through proper grounding.

The main service panel is the primary distribution point for electrical power in a building. Grounding this panel ensures that any fault current that may occur can safely travel to the earth, thereby reducing the risk of electrical shock and fire hazards.

Electrical enclosures, which house electrical equipment like circuit breakers and electrical components, must also be grounded. This connection to earth ground helps protect personnel from electric shock if there is a fault within the enclosure, as it provides a path for fault currents.

Equipment frames are the physical structures that support electrical appliances and machinery. Grounding the frames is critical because it helps prevent any buildup of static electricity and offers a path for fault currents. If a piece of equipment malfunctions, having its frame grounded ensures that electricity will not cause harm to users or damage to the equipment.

Therefore, grounding all these components—main service panels, electrical enclosures, and equipment frames—creates a comprehensive safety mechanism in an electrical system, confirming why the correct choice incorporates all of them.