1. What is AIC at Sub Panel?

AIC (Ampere Interrupting Capacity) at sub panel refers to the maximum short circuit current that protective devices at a sub panel can safely interrupt. It's calculated based on the main panel's short circuit current and the impedance increase between panels.

2. How Does the Calculator Work?

The calculator uses the AIC sub panel formula:

Where:

• \( I_{sc\_main} \) — Short circuit current at main panel (amps)
• \( \text{Impedance Increase} \) — Additional impedance between panels (decimal)

Explanation: The formula calculates the reduced short circuit current at the sub panel by accounting for the impedance increase in the circuit between the main and sub panels.

3. Importance of AIC Calculation

Details: Proper AIC calculation is essential for selecting circuit protection devices with adequate interrupting capacity, ensuring electrical safety and preventing equipment damage during fault conditions.

4. Using the Calculator

Tips: Enter the main panel short circuit current in amps and the impedance increase as a decimal value. Both values must be valid (current > 0, impedance ≥ 0).

5. Frequently Asked Questions (FAQ)

Q1: Why is AIC rating important for electrical panels?
A: AIC rating ensures that circuit breakers and fuses can safely interrupt the maximum possible fault current, preventing dangerous arc flashes and equipment damage.

Q2: How is impedance increase typically determined?
A: Impedance increase is calculated based on conductor size, length, material, and any transformers between the main and sub panels.

Q3: What are typical AIC ratings for residential panels?
A: Residential panels typically have AIC ratings of 10,000 to 22,000 amps, while commercial and industrial panels may have ratings up to 200,000 amps.

Q4: When should AIC calculations be performed?
A: AIC calculations should be performed during electrical system design, when adding sub panels, or when upgrading existing electrical systems.

Q5: Can this calculator be used for three-phase systems?
A: This calculator provides a basic calculation that applies to both single-phase and three-phase systems, though three-phase systems may require additional considerations for impedance calculations.