Electrician's Licensing Practice Exam

If a receptacle is connected to a subpanel, how must its grounding be managed?

1. Grounded to the main panel

2. Grounded to a dedicated grounding bar

3. No grounding is necessary

4. It can share grounding with other devices

The correct answer is: Grounded to a dedicated grounding bar

When a receptacle is connected to a subpanel, it is essential that its grounding is managed properly to ensure safety and compliance with electrical codes. Grounding the receptacle to a dedicated grounding bar within the subpanel is important because it provides a specific point where the grounding conductors can connect without introducing any potential ground loops or paths that could result in electrical shock hazards. Dedicated grounding bars facilitate a proper and organized means of grounding all circuits that depend on that subpanel. This method also ensures that the grounding system is effective in discharging any fault current safely back to the ground, helping to maintain the integrity of the entire electrical system. It is crucial to follow this practice as it aligns with the National Electrical Code (NEC) guidelines that stipulate proper grounding of receptacles and devices, especially in setups that include separate structures or detached units running on subpanels. While other options may propose different grounding methods, such as connecting to the main panel or sharing ground with other devices, these alternatives can compromise system safety and integrity, and thus are not recommended or compliant with best practices in electrical installations. Ensuring that each receptacle connected to a subpanel has its grounding managed through a dedicated grounding bar supports a safe and reliable electrical system.