Mismatched wiring and solid vs stranded

[Watts Happening]

Looking for educated opinions!

It’s looking like I’ll only be able to fit 15 of the 16 panels I’ve ordered on our pergola. That said, I have to split them into two strings instead of 8s2p it’ll be one in 8s, one in 7s. Roughly 10 amps max per string.

Probably a total of 60-70 feet back to the Sol-Ark. I already pulled a pair of stranded 10awg THWN wire expecting to have 20 amps running down the wire at about 400v. I thought I had more than I did and ran out with a single run.

I have plenty of 12awg solid THWN, and one roll of red 12awg stranded.

Do I:

A) Buy more 10awg stranded and satisfy my inner wiring nazi self

B) Use existing wire and pull one red stranded 12awg and one solid black 12awg

C) Pull two of the red stranded 12awg and relabel one with black tape on each end

D) Pull one white and one black solid 12awg and relabel white to red

E) Shut up, it doesn’t matter, you’re overthinking it

 

[wheelman55]

Use one of the many voltage drop calculators found online. I use the Southwire one.

You’ll get your answer.

 

[Watts Happening]

Use one of the many voltage drop calculators found online. I use the Southwire one.

You’ll get your answer.

I appreciate the response, but I’m well aware of the ampacity requirements and all every wire referenced is more than capable of the distance, voltage and amperage.

It’s really coming down to being adhd with wiring, purely looking at what others would do

 

[DIYrich]

E, B. I like the different colors, and not having to use tape.

 

[wheelman55]

Understood?

Does 3P5S work for you? Then you could run even more wire?

 

[Watts Happening]

Understood?

Does 3P5S work for you? Then you could run even more wire?

Oh lord, I’d love to lol!

Maybe I’ll just use the conduit as the ground wire for all of them haha!

 

[DIYrich]

Oh lord, I’d love to lol!

Maybe I’ll just use the conduit as the ground wire for all of them haha!

3p5s into a combiner on the roof? Too many amps for the 10 awg?

 

[Watts Happening]

3p5s into a combiner on the roof? Too many amps for the 10 awg?

I suppose that could be option F. Looking at 30 amps, higher than I’d like but still rated fine.

 

[DIYrich]

I suppose that could be option F. Looking at 30 amps, higher than I’d like but still rated fine.

View attachment 164724

250 v?

 

[Watts Happening]

250 v?

Ballpark, yes.

 

[CoolWill]

B then E.

A costs too much for no reason. C and D are technical code violations because you can't re-color a conductor smaller than #4.

 

[Watts Happening]

B then E.

A costs too much for no reason. C and D are technical code violations because you can't re-color a conductor smaller than #4.

I would agree, but I don’t know that said code violation is relevant when dealing with DC PV wire. I’ve seen many people mention using purely black wire is legal.

 

[Checkthisout]

Fawk it. Run it and see what happens.

If you wait until it snows, snow melting around the wire would be indicator that it's undersized

 

[Watts Happening]

Fawk it. Run it and see what happens.

If you wait until it snows, snow melting around the wire would be indicator that it's undersized

 

[CoolWill]

I would agree, but I don’t know that said code violation is relevant when dealing with DC PV wire. I’ve seen many people mention using purely black wire is legal.

I checked and you're right that the code about PV conductors doesn't have a color restriction. However, still B then E.

 

[Watts Happening]

I checked and you're right that the code about PV conductors doesn't have a color restriction. However, still B then E.

Thanks for checking, I appreciate that.

I agree 100% on the E

I’m 50/50 on the B. It feels so wrong!

 

[rodrick]

Thanks for checking, I appreciate that.

I agree 100% on the E

I’m 50/50 on the B. It feels so wrong!

The only real difference in option b is stranded is easier to pull

 

[Zapper77]

A, E

 

[DIYrich]

I’m 50/50 on the B. It feels so wrong!

both are rated 12 awg. Stranded may be a little bigger to compensate. But, I thought current travels on the surface of the wire, so stranded should be better?

 

[timselectric]