How is a residential building’s electrical system typically grounded?

A residential building's electrical system is typically grounded via a ground rod connected to the main electrical panel. This method establishes a direct connection between the electrical system and the earth, which is essential for safety. The ground rod, usually made of copper or galvanized steel, is driven into the ground and helps dissipate electrical surges, stray voltage, or lightning strikes into the earth, thus minimizing the risk of electrical shock or fire.

Grounding enhances the effectiveness of overcurrent protection devices, such as circuit breakers or fuses, by ensuring they operate correctly under fault conditions. This connection aids in preventing the buildup of excess voltage that can occur during an electrical fault, thereby protecting both the system and the people using it.

Other options mentioned do not provide an adequate grounding solution. Insulated conduits may protect wiring but do not serve to ground the system. Grounding screws on appliances contribute to the safety of those specific devices but do not act as the primary grounding method for the entire electrical system. Similarly, having grounding wires in every outlet is important for appliance safety but does not establish the foundational ground connection that the main panel provides through a ground rod.