And connectors, and terminals and adapters and...
Just a quick tip coming from experience. I was out in the Solar Shed, today, pulling wire to add a couple more panels to my Non-Export Grid Tie experiment. I’ve been running 1200 watts, being shared by two GT inverters. Now it is 1800 watts. Soon, it’ll be 2400 and live on the grid instead of in the lab.
I have the giant spool up on a rack on the back of one of my electric trucks so I can point myself in the right direction and run with the end of the wire. Apparently I have been doing that a lot, because I am starting to see the core. I checked the number on the side of the spool with the number on the wire and, yep, getting close to 1000 feet that’ve been used. The Shed is 80′ long, now, so some of the wire pulls are pretty lengthy. I had hoped that spool would last me through the next addition to the Solar Shed, but looks like I’ll have to buy another spool. Tip: write on the side of the spool the first footage number you find on the wire so you can keep up with how much you’ve used and make sure your vendor is straight with you.
I rummaged in my parts drawer and found MC4 splitters and enough connectors for the job, but not enough for the next and final step to a total of 8 modules on this project. Then it dawns on me, using the splitters I’ll have too much current on that #10 wire, so that means perhaps another 80′ of wire. AND, naturally, I didn’t have enough pins for the connectors. As I progress with the Shed, things are gradually getting more organized, but there was difficulty finding the sack of MC4 connectors I knew I had recently (sometime this year) bought. I finally found them and was in business. Hooray! When I finished, I put them in the new parts bin, an old lateral file from Goodwill. Lateral file cabinets are showing up everywhere as businesses put everything in digital form in the “cloud”. A friend paid $15 for one, I think, and they told him they had a bunch more he could just have at no cost. They are wonderful for storing parts. I have plastic tote bins in mine to separate the parts.
You can, of course, buy pre-made cables, and they’re fine if they come with a kit, but do you really want to stop your project and order stuff every time something turns up a bit short or you make a change? For a bigger system, you’ll also find buying wire and cable in bulk can save a bunch. I’ve bought the big 1000′ spool of solar wire, full 100′ spools of 00 and 0000 cable, sacks full of MC3 and MC4 connectors, and buckets of terminal ends for battery cables. Yeah, it hurts really bad when you buy a big spool of cable, but ultimately, it hurts a lot less than buying by the foot or by the finished cable. Not only that, it gives you the resources to make changes or additions when you are ready to do so and not when the postman or UPS dude brings your small order two weeks later.
It’s also good to have some spare hardware when Stan-the-Hermit comes buy looking for some stuff for his system. He may be too late to get into THIS spool of wire.
–Neal