New York State Master Electrician Practice Exam

What is the required minimum cross-sectional area of the internal bonding bus of a multisection switchboard?

1. 1/4 sq inch

2. 1/2 sq inch

3. 1 sq inch

4. 2 sq inch

The correct answer is: 1/2 sq inch

The minimum cross-sectional area of the internal bonding bus of a multisection switchboard is specified to ensure that the bonding connections can adequately handle fault currents and maintain system integrity. For a multisection switchboard, the bonding bus is crucial for providing a low-resistance path for grounding and bonding, which enhances the safety and reliability of the electrical system. A cross-sectional area of 1/2 square inch is deemed sufficient to manage potential fault currents and mechanical stresses while keeping the resistive losses to acceptable levels. This size also helps in prevent overheating during normal operations and fault conditions, ensuring that the bonding system remains effective. Additional context for this requirement is found in the National Electrical Code (NEC) and other relevant standards, which provide guidelines on grounding and bonding to ensure electrical safety. By adhering to these specifications, electricians can help prevent electrical shocks, equipment damage, and other hazards that may arise from inadequate bonding.