Journeyman Electrician Practice Exam

Which of the following describes a permissible method for grounding a concrete-encased building steel?

1. Use of a size 6 AWG copper conductor

2. Connection to the nearest electrical panel

3. Size according to local jurisdiction regulations

4. Size based on the largest grounding electrode conductor required

The correct answer is: Size based on the largest grounding electrode conductor required

The permissible method for grounding concrete-encased building steel is based on sizing the grounding electrode conductor according to the largest grounding electrode conductor that is required. This approach is correct because the National Electrical Code (NEC) mandates that the size of the grounding electrode conductor should be determined by the size of the largest conductor that is connected to it. This ensures that the grounding system can safely carry fault currents and provides adequate protection against electrical shock and fire. Grounding concrete-encased steel properly ensures that the structural elements of the building provide an effective path to ground in case of a fault condition, which enhances the overall safety and reliability of the electrical system. Adhering to this method also aligns with the NEC requirements, which specify that the minimum size of the grounding electrode conductor for building steel must correspond to the size of the largest ungrounded service-entrance conductor. Thus, choosing the size based on the largest grounding electrode conductor ensures compliance and safety.