New York State Master Electrician Practice Exam

What is the maximum voltage drop allowed from the service point to the last over-current device in a dwelling unit?

1. 2%

2. 4%

3. 6%

4. 8%

The correct answer is: 4%

The maximum voltage drop allowed from the service point to the last over-current device in a dwelling unit is set at 4%. This requirement is based on established electrical codes which aim to ensure efficient operation of electrical systems, prevent excessive energy loss, and guarantee safe and reliable performance of electrical devices. A 4% voltage drop from the service point is generally deemed acceptable for most circuits, as it allows for minimal energy loss while still maintaining adequate voltage levels at the end-use devices. Keeping the voltage drop within this limit helps to ensure that appliances function optimally without overheating or malfunctioning due to insufficient voltage. While other percentages are often considered for specific scenarios or applications, the 4% standard specifically addresses residential settings and aligns with best practices in the industry, promoting safety and efficiency in electrical installations.