The AIC Rating Indicates the Device's Ability to Interrupt Which of the Following?

• A. Voltage Spike
• B. Normal Operating Current
• C. Maximum Fault Current the Device Will Interrupt
• D. Transient Fault Current

Answer: (C)

The AIC rating tells you the maximum fault current the device can interrupt safely. It’s about short-circuit (fault) currents: the device must be able to open the circuit and clear the fault without its contacts welding shut or failing. In a real system, the prospective short-circuit current at the device’s point of installation is what determines the required AIC. If the fault current exceeds the device’s AIC, it may not interrupt properly and could fail catastrophically.

This differs from normal operating current, which is simply the continuous current the device is designed to carry, and from voltage spikes or transient fault currents, which are different phenomena that aren’t what AIC measures.