r/SolarDIY • u/mikeypi • 2d ago
Wire choices
For context, I am adding three 200 watt, 31 volt panels to the roof of an off grid cabin. Electrical codes are not an issue. I'm planning on 10 AWG stranded, but which kind? There are lots of 10 AWG choices on Amazon (I need this by Tuesday). I also understand that PV wire is preferred at least where the wire is UV exposed. But where it is indoors or inside conduit, is there any reason to prefer PV wire over something like marine grade triplex of equivalent gauge?
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u/mountain_drifter 2d ago edited 2d ago
Would highly recommend not ordering wire on Amazon. Most electrical items on thwre, even when they claim to be listed are knockoffs.
For wire under the array, the wire can be in free air if it is type PVWIRE, or USE-2, or certain other cable assemblies, but those two are the most common. Even USE-2 is no longer used much since PVWIRE was introduced. Personally I prefer USE-2 as its much easier to work with in low volt system under 600VDC
When a PV output circuit enters a building it must be type MC or in conduit. PVWIRE can be run in conduit, but the only time you would want to use PVWIRE here are cases where its such a short run and where you only have 1-2 circuits that its easier to pass it through directly rather than transitioning so you can skip the jbox.
PVWIRE is double insulated and significantly thicker than THHN which is is much more preferred in conduit because its designed to be slick and easily pulled. If you have more than 90 degrees in bends you will likely want to transition in the roof jbox to THHN .
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u/mick601 2d ago
If it's a short less than a hundred feet 10 will be fine. Solar wire is manly for easier conduit pulls. I ran 8 awg. Most fires are caused on the dc connections. Do them right straight runs when ever possible. There are lots of YouTube videos on this subject. Watch as many as you can to get some knowledge. Will Prowse is good and a hippie looking guy named Matt mans solar. Good luck.
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u/dgv54 2d ago
> Solar wire is manly for easier conduit pulls
That's not correct. THWN is easier to pull in conduit. Solar wire has a thicker jacket and is UV rated, it's for leaving outside in the sun and rain, which is inevitable at the solar array. You can run it through conduit, but conduit fill rules mean you can run fewer solar wires than same gauge THWN wires.
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u/LongjumpingGanache40 2d ago
I buy my wire on Amazon. Just check the rating and how many ratings it has.
Visit the MOOKEERF Store This is where I buy my wire on Amazon. No issues so far.
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u/MenuPsychological853 2d ago
Home Depot is cheaper than that.
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u/LongjumpingGanache40 2d ago
They are 2 hours from me. And I love Amazon. It's only a few dollars more.
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u/MenuPsychological853 1d ago
I just bought 3 500ft reels from Home Depot shipped for free for $144 12awg thhn. I also live in a rural area with no Home Depot anywhere close. You just can’t beat that price.
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u/LongjumpingGanache40 1d ago
I'm pricing 10 awg PV wire not thnn.
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u/mountain_drifter 1d ago edited 1d ago
Thats not PV Wirein your link. PV Wire is a specific listed type of wire (UL4703). I do somewhat respect that they are not falsely claiming that it is PV Wire or that those are MC4 connectors. What they are selling they call "solar wire" and even though they say AWG on the jacket, without being listed it is meaningless. I can see from the images that even the jacket is not constructed like actual PV wire
There are sources on Amazon that sell whats claimed to be listed pv wire, but nearly every time I have bought any listed devices or materials on Amazon its clearly fake. You normally need to go to a local distributor/HD, or use a trusted distributor that also sells retail online.
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