About the AC Cable Sizing
AC cable sizing selects the conductor from the inverter to the LT panel or grid connection so it safely carries the current and keeps voltage drop within limits (commonly ≤3%), per IS 732 / IEC 60364.
Formula
V_drop (3-φ) = √3 × I × L × (R·cosφ + X·sinφ)
- I
- Line current (A)
- L
- Cable length (km)
- R, X
- Cable resistance & reactance per km
- cosφ
- Power factor
How to calculate it
- 1Compute the inverter output current from its AC rating and voltage.
- 2Pick a cable whose ampacity (after derating for grouping/temperature) exceeds that current.
- 3Check the voltage drop over the run stays within the limit (typically ≤3%); upsize if not.
What you can calculate
- IS 732 compliant
- 1φ & 3φ
- Temp derating
- Voltage drop
Standards & references
Frequently asked questions
What size cable do I need for a solar inverter?
It depends on the inverter's AC current, the run length, and the derating for temperature and grouping. Size the cable so its derated ampacity exceeds the current and the voltage drop stays under about 3% — then round up to the next standard size.
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