How To: Find The Cable Size Formula

Disclaimer: This write-up is for educational purposes. Electrical installations must comply with local wiring regulations (such as the NEC, BS 7671, or IEC standards) and should be verified by a certified electrician.

For direct current (DC) or standard single-phase alternating current (AC), the formula is: how to find the cable size formula

This calculation gives you the minimum current the cable must carry. You typically select a cable rated higher than this calculated value to account for future expansion or ambient temperature derating. Disclaimer: This write-up is for educational purposes