What is the Gauge Wire Used on the Harbor Freight Kit?

I am guessing 18 ga stranded, as I am going to replace what came with it to a 16 gauge stranded since my run is going to be about 50 feet or should I make the wires larger gauge?


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Here is the chart I have been using and relying on for years. Don't do a thing until you check it first!

Amps    #12    #10     #8      #6      #4    #3     #2      #1   #1/0    #2/0

4           22.7   36.3   57.8   91.6   146   184   232    292    369    465   feet

6           15.2   24.2   38.6   61.1   97.4  122   155    195    246    310

8           11.4   18.2   28.9   45.8   73.1  91.8  116    146    184    233

10           9.1   14.5   23.1   36.7   58.4  73.5   92.8  117    148    186

12           7.6   12.1   19.3   30.6   48.7  61.2   77.3  97.4   123    155

14           6.5   10.4   16.5   26.2   41.7  52.5   66.3  83.5   105    133

16           5.7     9.1   14.5   22.9   36.5  45.9   58.0  73.0   92.0   116

18           5.1     8.1   12.9   20.4   32.5  40.8   51.6  64.9   81.9   103

20           4.6     7.3   11.6   18.3   29.2  36.7   46.4   58.4   73.8   93.1

25           3.6     5.8     9.3   14.7   23.4  29.4   37.1   46.8   59.1   74.5

30           3.1     4.8     7.7   12.2   19.5  24.5   30.9   38.9   49.2   62.1

35           2.6     4.2     6.6   10.5   16.7  20.9   26.5   33.4   42.2   53.2

40           2.3     3.6     5.8     9.2   14.6  18.4   23.2   29.2   36.9   46.5

Thanks Ray, but the HFpanels do not come with wires that large, I was just wanting to put a uv resistant cable on the panels, but according the chart the wires would be huge compared to what came on them originally.

I used 16ga landscape wire from Home Depot on my ICP 15w panels. Its UV rated.

Thanks Hoopty_yo

10ga outdoor wire run 110ft from my array to my cabin. There seems not to be a loss. See my pics.

Take into consideration that the kit is less then 3 amps and how long is the wiring in your kit? You are talking 50 feet here. That changes everything.

Trust the chart.    

Craig, I'm a bit confused and I think it is because you mentioned the distance of your run in with the rest of the question. Think we have two kinda unrelated things going on here. Most of us use the existing leads all going into a combiner box - then the appropriate, (or heavier in my case), gauge of wire pair for the run from the combiner box to the controller based on the same chart Ray put up. Unless there is some other over-riding reason to replace them, I would use the existing HF panel wires going to the combiner box then cover them with a UV resistant spiral wire wrap if they are left out in direct sunshine/weather.

LDsecure is talking about his run from the combined wires to his controller.  There will be a measurable power loss when running direct current over a wire of *any* gauge for an appreciable distance - what is at question is what is an "acceptable" power loss for the intended purpose.  If I remember correctly, that chart Ray uses is based upon an acceptable loss assumption of 3%, (I may be wrong there).  I am somewhat of a miser and would use the next gauge larger, figuring to get better overall performance in power generation in the long run, (not to mention allowing a bit of slop if I decide to break the piggy bank and add another kit or 3 - which is "more than likely" going to happen).  We also have the option of rewiring the panels for 24v or higher to reduce current and save on having to break the bank again to replace wire. Of course your controller has to be able to handle the greater input voltage.

Sheesh - I hope all of that made some kind of sense Craig.  A bit tired tonight after Easter preps for the grandkids.

Couldn't agree more, figure out what you really need and "super size" from there.

Thanks guys, I understand what everyone has said , but it seems like the hf panel wires are cheap flimsy and not uv rated, I really just wanted to replace them with a uv rated cable probably 10 ga. solar cable from a solar store in town,  What I need to do is put my combiner junction box closer and then go from there to the controler.


I am going to use the chart numbers Ray, I appreciate the info ,  Oh and Dave I always confuse people I speak the language of dyslexia lol .My wife goes nuts  . So If I do not change wires I will do the uv rated spiral wire wrap.


thanks again very much appreciate the input.

Hello Craig,


Dave and Ray are on the mark for the wiring. As you noted the wire is cheap and flimsy, but for the distance amount of power being produced by each panel they are perfect for their purpose. I don't believe you will gain anything by changing the wire to the panels. But I do just as everyone else has done. I combine them all at the panels and then run heavy gauge welding cable from the combiner box to the charge controllers. Because of the amperage of my system I also needed to move mine to 36v to minimize the loss.

I would invest my time and money from the combiner box to the charge controllers. This will give you the best results.



     I have a 150 foot run from my panels to camp and when the sun is out I have been getting 8 or more amps . I used a 10 stranded to make my run to camp . Planning on going to 24V to get more out of what I have .


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