The AIC Rating of an Overcurrent Protection Device Represents Its:

• A. Maximum Fault Current the Device Will Interrupt
• B. Voltage Rating
• C. Normal Operating Current
• D. Short-Circuit Current at Trip

Answer: (A)

AIC stands for Amps Interrupting Capacity, and it represents the maximum fault current the protective device can interrupt safely. In other words, it shows how large a short-circuit current the device can break without its internal parts failing or the contacts welding shut. This is about interrupting capability during a fault, not about the normal current it carries or the voltage it can withstand. The voltage rating tells you the highest voltage the device is designed to operate with, while the normal operating current is the continuous current the device is intended to carry during regular operation. The current at which a device trips is a protective characteristic, not the limit of what it can interrupt. When selecting protection, you size the device so its AIC is at least as high as the prospective fault current in the system. For example, if the system could produce up to 6 kA during a fault, you’d choose a device with an AIC of 6 kA or higher.