wire size

ws9876

Would you use 10/3 Romex  solid to join a 2500 watt inverter  120v to a mains panel 65 ft away?

mcgivor

Romex or NMD 90 has restrictions for its useage, particularly with regards to mechanical protection, if running a single 120V circuit a 2 conductor cable is all that's required Note. The third uninsulated ground in a 10/2 is not counted as a conductor.

For 65 feet with 10 AWG the voltage drop would be acceptable at 2500W load at 2.6% voltage drop https://www.calculator.net/voltage-drop-calculator.html?material=copper&wiresize=3.277&voltage=120&phase=ac&noofconductor=1&distance=65&distanceunit=feet&amperes=20&x=31&y=26

ws9876

would you use 10/2 romex solid from solar panels 50 ft to charge controller?? or would you use 2 pieces of 10 awg copper stranded?

BB.

Stranded or solid does not really matter electrically or for straight runs... Stranded will be much easier to bend and get around corners.

When you get to larger AWG wiring (like 8 AWG or larger), it is generally easier to work with stranded.

-Bill "I am not an electrician" B.

Estragon

I'd be inclined to use stranded if/where subject to vibration or other movement (wind etc).  Stranded can be tough to get properly  into a tight connector though.