Different sizes and sets of arrays to one Breaker Wire size derating?

CTritz

Dumb question 

Can we down size the A/C wire from one small set of panels JB  10.64 Amps #12.  

And splice another set of 13.3 Amps #12  to a #10 to the panel ? 

Instead of a #10 to each set ? 

It’s a huge wire savings ?   It’s for my home 

CTritz

i wouldn’t do it when it’s a load.  (Different sizes of Baseboard heaters).  But solar is limited to the infeed of power. 

BB.

The sizing of the solar array wiring is both based on maximum sustained current (and short circuit current Isc), insulation rating, ambient temperatures, UV resistant insulation (if in sun), etc...

For solar, many times with solar, we use larger AWG copper wire to resist voltage drop for longer runs.

For "complicated" wiring questions... Such as multiple solar panels in parallel, using fuses/circuit breakers and such to ensure that the individual panel/string wire runs are protected against failures in other ways... Such as 4x parallel strings--One string gets a short/fault to ground, then the other 3x "good" parallel strings feed 3x Isc into the one faulted string--Need fuse/breaker to prevent the three parallel strings from feeding too much current into the faulted panel/string and starting a roof fire (one example).

-Bill