wire question

RedNeckSolarManRedNeckSolarMan Solar Expert Posts: 34
Hello everyone, I have question, what would you recommend of what kind of wire to use from solar panel to charge controller. I have 20 watt solar panel, I was using 10 gauge indoor wires and I don't know if that is good wire to use or not. Thank you for reading my post and have a nice day.


  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: wire question

    Need to know the Vmp/Imp of the panel and how far from the panel to the charge controller.

    The problem with "indoor" wiring is that the insulation will probably break down from the ultraviolet light of the sun.

    Also, you may end up with issues of high temperature in sun/conduit (if any) causing the insulation to melt or harden and fail.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • icarusicarus Solar Expert Posts: 5,433 ✭✭✭✭
    Re: wire question

    Indoor wire (romex) has a paper insulation which will get wet outdoors, leading to problems eventually.

  • RedNeckSolarManRedNeckSolarMan Solar Expert Posts: 34
    Re: wire question

    VMP is 17.39v and IMP is 1.16a and distance from solar panel to charge controller is about 5 feet. That is good info about indoor wire with weather.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: wire question

    unless the sun eats away at the insulation then don't worry about it as the losses are quite low. if you worry about the insulation then nearly any wire with outdoors rated insulation will work up to #22 for under 2%.
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