Wiring Connection Issue

[Oliminator]

Hi Guys, I'm attempting an install and doing some initial studying. One thing I'm not comprehending is the wiring. I have a long run from the panels to my inverter. The online wire size calculators call for 8 awg and I decided to go with 6 awg. My panels have 10 awg with mc4 connectors. Do I connect the panels together with 10 awg and only use the 6 to make the run between the final panel in the string and the inverter, or, do I connect the panels with 6 awg as well? If I use 6 awg all the way down, how do I connect 6 awg to an 10 awg mc4 connector? If I use 10 awg for the panel connections, how do I hook up the final connection of the 10 and the 6 awg?

[foo1bar]

One solution would be to have a junction box and inside the junction box make the connection between the 10AWG PV-Wire and the 6 AWG THWN wire that you'll run to the inverter.
You could use something like a Polaris connector to make the connection. (make sure the box is big enough for them)

BTW - are you sure you're doing the calcs right for the long run?
How many amps will you have at max power?
And what voltage?
Most of the online calculators you plug in either 240V or 120V because it's meant for household AC power. But you probably will be running at 400V or 500V DC for that run.

[SunEagle]

Depending on how you are wiring your panels (series/parallel) some type of combiner box or junction box is your best bet to convert to a larger wire size.

I built a combiner for 5 parallel wired panels with the #10 and MC4 connectors going to the panels. Inside the box I included fuses for each panel and then exited the box with a single pair of wires that go to my charger.

You can do something similar but instead of fuses you just use a terminal block that allows you to connect the #10 awg from the panels to the #6 awg to the inverter.