New York State Master Electrician Practice Exam

How should grounding terminal buses of normal and essential branch-circuit panelboards serving the same area be connected?

1. Using copper conductor not smaller than 12 AWG

2. Using insulated continuous copper conductor not smaller than 10 AWG

3. Using aluminum conductor not smaller than 8 AWG

4. Using copper conductor without insulation

The correct answer is: Using insulated continuous copper conductor not smaller than 10 AWG

The connection of grounding terminal buses for normal and essential branch-circuit panelboards serving the same area is crucial for safety and compliance with electrical codes. The use of an insulated continuous copper conductor not smaller than 10 AWG ensures that the grounding system is effective in providing a solid connection to the earth, minimizing the risk of electrical shock and equipment damage. Utilizing an insulated conductor helps prevent unintended contact with other conductive materials, which could potentially lead to short circuits or other hazardous conditions. The choice of a 10 AWG size ensures that the conductor is adequately sized to handle fault currents without overheating or failing, while the insulation promotes safety in scenarios where the grounding conductor could be exposed to physical damage or environmental factors. In contrast, using a conductor of a smaller gauge would not provide sufficient capacity for fault conditions, and using aluminum is not recommended in this scenario due to its lower conductivity and potential for corrosion, which could compromise the grounding system. The option of a non-insulated copper conductor raises serious safety concerns, as it could become a shock hazard if it comes into contact with live components. Therefore, the decision to use an insulated continuous copper conductor not smaller than 10 AWG aligns perfectly with the best practices for grounding connections in electrical installations.