New York State Master Electrician Practice Exam

What percentage of the ampere rating of a switch should be the maximum for controlling inductive loads?

1. 25%

2. 50%

3. 75%

4. 100%

The correct answer is: 50%

The correct answer is that the maximum percentage of the ampere rating of a switch for controlling inductive loads should be 50%. When dealing with inductive loads, such as motors and transformers, it’s important to consider the inrush current, which can be significantly higher than the normal operating current. Inductive loads also create a phase difference between voltage and current, which can lead to additional stress on the switch. Given this context, limiting the operational capacity of the switch to 50% of its rated ampacity helps to mitigate potential damage and ensure better performance by allowing a safety margin for the inrush and operational currents. This percentage is a standard practice to enhance the longevity of electrical components and protect the circuit from overload conditions. Reducing the load to this level not only facilitates a safer operation but also aligns with the best practices established in electrical codes and standards for managing inductive loads effectively.