HOLT Electricians Practice Exam

The ampacity of capacitor circuit conductors should not be less than what percentage of the rated current of the capacitor?

1. 100%

2. 125%

3. 135%

4. 150%

The correct answer is: 135%

The ampacity of capacitor circuit conductors is a critical consideration to ensure safe and efficient operation of electrical systems. The correct percentage that conductors should not fall below is 135% of the rated current of the capacitor. This standard takes into account the fact that capacitors can draw inrush currents that are significantly higher than their steady-state operating current. By specifying that conductors should have an ampacity of at least 135% of the rated current, the standard aims to prevent overheating and potential damage to the conductors during this inrush condition. It also ensures that the conductor can handle any transient conditions or motor starts without risking failure or tripping circuit protection devices. This guideline helps align with safety protocols and best practices in electrical design, promoting reliability and minimizing the risk of electrical hazards. In contrast, lower percentages such as 100% or 125% may not provide adequate margin for these inrush currents, while 150% might be unnecessarily conservative in many applications. Thus, 135% strikes a critical balance between safety and efficiency.