How can I calculate wire size to go from a solar array (of 36 panels, 365W & 42V each) to a shed with an inverter 50 ft away?

  • 1
    What is the series/parallel arrangement? Are all panels paralleled (42V to the inverter)? Or are they series/parallel strings? Commented Oct 8, 2022 at 1:51
  • 2
    Not setup yet. I am buying a kit from shopsolarkits.com. Sounds like talking to a solar specialist might be a must ;)
    – i--
    Commented Oct 8, 2022 at 1:53
  • 3
    Yes, solar and off-grid power are fairly demanding of technical skills. Commented Oct 8, 2022 at 1:55

1 Answer 1


I am no electrician, but from what I am reading - wattage and voltage accumulate with every new panel, while amperage stays the same. Hence my AMP would be 365/42 = 8.7 A. Using this calculator my gauge should be 16 AWG (1,512V, 9A, 50Ft, 1% loss). This seems too thin.

  • Comments are not for extended discussion; this conversation has been moved to chat.
    – BMitch
    Commented Oct 8, 2022 at 14:02
  • Conceptually, could be add A, add V or a mix. But can't be strictly add V in your case because 36 * 42 = 1,512V - that's way beyond normal residential wiring. Commented Oct 9, 2022 at 0:26
  • 1
    Depending how you connect the panels you can increase the current for the same voltage or increase the voltage for the same current - approximately... HOWEVER, when I siz3ed my cables I looked at the voltage and current maxima and then chose a cable to exceed the current by 20%, and also make sure of the voltage ie insulation - I am well aware of voltage drop ie losses. Even the electrician who came to commission our system said he was impressed.
    – Solar Mike
    Commented Mar 7, 2023 at 7:28

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.