American Home Inspectors Training (AHIT) Practice Test

In a sub-panel, how should the neutral and ground wires be configured?

1. They should be combined

2. They should be separated, and neutral isolated

3. They can remain connected

4. Ground should be isolated

The correct answer is: They should be separated, and neutral isolated

In a sub-panel, the correct configuration for the neutral and ground wires is to have them separated, with the neutral isolated from the ground. This is important for safety and proper operation of the electrical system. When neutral and ground are combined in a sub-panel, it can create a potential hazard known as a "ground loop," which may lead to shock hazards or equipment malfunctions. In addition, if a fault occurs and current flows on the neutral, it could energize the grounding system, increasing the risk of electric shock. Isolating the neutral wire from the ground in the sub-panel ensures that the grounding system remains a dedicated path for fault current, while the neutral is solely for returning current from the load. This separation helps maintain a safe and effective electrical distribution system. Ground wires should connect to the grounding bus bar, which in turn connects to the ground electrode system. The neutral wires connect to a separate neutral bus bar, which is isolated from the ground bus. This configuration is required by electrical codes to promote safety and prevent electrical issues.