ICC Residential Electrical Inspectors Practice Exam

What is the minimum size EGC required for a 70 AMP circuit?

1. 6 AWG

2. 8 AWG

3. 4 AWG

4. 10 AWG

The correct answer is: 8 AWG

The minimum size Equipment Grounding Conductor (EGC) required for a 70 AMP circuit is determined by the National Electrical Code (NEC) guidelines, specifically found in NEC Table 250.122. According to this table, the size of the EGC depends on the rating of the overcurrent protection device. For a 70 AMP circuit, the table indicates that the minimum acceptable size for the EGC is 8 AWG copper or 6 AWG aluminum. This is crucial for ensuring safe operation and protection against faults. The EGC serves to safely conduct any fault current back to the source, allowing the overcurrent protective device to operate effectively and minimize the risk of electric shock or fire hazards. The emphasis on using 8 AWG copper for this specific rating highlights the importance of adherence to established regulations aimed at promoting electrical safety. Using a conductor that is too small may not provide adequate current-carrying capacity, potentially leading to overheating or failure to trip the circuit under fault conditions, which could have serious consequences in a residential setting. This underscores the necessity for inspectors and electricians to follow code requirements closely for grounding conductors, ensuring the integrity and safety of the electrical system.