Wire Size Calculator
The Wire Size Calculator provides a simplified estimation of the minimum electrical wire gauge (AWG) required for HVAC components or other electrical loads. It primarily considers the load current (amperage) and conductor material (copper or aluminum) to determine a size based on standard ampacity tables (e.g., NEC Table 310.16 at 75°C). Optionally, it can perform a basic voltage drop calculation if the circuit distance, system voltage, and maximum allowable voltage drop percentage are provided. The final recommended wire size should satisfy both ampacity and voltage drop requirements.
Understanding Wire Gauge (AWG): AWG is a system where smaller numbers mean larger wire diameters and higher current-carrying capacity (ampacity). Circular Mils (CM) measure cross-sectional area; larger CM means lower resistance and less voltage drop. Both ampacity (based on NEC tables) and voltage drop (to prevent equipment malfunction) must be considered.
This calculator provides a basic estimate and is NOT a substitute for the National Electrical Code (NEC) or professional electrical design. It does not account for all factors like ambient temperature corrections, conductor bundling derating, terminal temperature limitations, or specific overcurrent protection device (OCPD) rules for motors). ALWAYS consult the current NEC and a qualified electrician for safe and compliant electrical installations. Incorrect wire sizing can lead to fire or equipment damage.