Journeyman Electrician Practice Exam

What is the minimum size grounding conductor for an installation with multiple parallel conductors?

1. Size according to largest parallel conductor

2. Depends on the circuit voltage

3. Size based on the grounding electrode system

4. Standard minimum of 8 AWG

The correct answer is: Size based on the grounding electrode system

The minimum size grounding conductor for an installation with multiple parallel conductors should be sized based on the grounding electrode system. This is important because the grounding conductor serves to create a safe path for electrical current to return to the ground in the event of a fault. The ground electrode system, which includes items such as ground rods, plates, or building steel, determines how effectively the grounding system can disperse electrical energy into the ground. In sizing the grounding conductor, guidelines are provided in the National Electrical Code (NEC), which specifies that the grounding electrode conductor must be adequate to connect to the grounding electrode system and capable of handling potential fault currents safely. This sizing criterion is important for ensuring the protection of equipment and personnel, as it ensures that the grounding system can adequately respond to fault conditions, regardless of the sizes of the parallel conductors. Points about the other options highlight that the largest parallel conductor or circuit voltage alone do not directly influence the grounding conductor size, as the main consideration is the effectiveness of the grounding electrode system overall. Additionally, a standard minimum size of 8 AWG does not apply universally to all situations but rather depends on the specifics of the installation and code requirements rather than being an arbitrary fixed size.