Will this wire work for a temp fix?

[myersfamilyhome]

So I need to make a temporary 30' run from a charge controller to a PV array and I already have a 40' red nylon coated THHN stranded and 40' black nylon coated THHN stranded that I can use. The PV array is configured in series parallel to push a max of 90v@19a to a 100/20 mppt. It's my understanding that 40'/20A@3%V Drop is doable with 6AWG. Is there any reason why I can't use this wire until I get the right type?

 

[Hedges]

Voltage and current are fine for THHN, in fact 6 awg can carry much more current.
Used in conduit, it would be proper wire. If simply exposed, it will be functional but not code compliant. It is exposed to damage without an outer jacket or conduit and will deteriorate in sunlight.

Voltage drop isn't critical for PV, they way it is for SCC to battery, battery to inverter, or AC connections. If 19A is Isc, 10 awg would be sufficient for ampacity/current rating and system would still operate, just a bit more power loss.

 

[myersfamilyhome]

Cool, just needed a temp fix and didn't want to cut the wire if I didn't need too. Was pretty confident that it would work numbers wise but every so often you get to second guessing yourself regardless of how things add up lol. Much appreciated

 

[Hedges]

Don't make a tight coil of the excess wire, leave it spread out for cooling (although you're running 1/3 of rating so not really a problem.)
I once used a large coil of 12/3 UF at 30 amps. Don't break more than one rule at a time. I had to cut out the melted/shorted portion, only have shorter length of usable wire remaining.

 

[myersfamilyhome]

Gotcha, yeah I figured it's never good to stack/bundle anything that can conduct heat. The current still has to travel same distance but heat on heat doesn't help and can lead to damage to insulation quicker and possible short