Just in the Nick of Time

DSCN1336 cropped

The new solar array, powered up (and nearly invisible) just as the first snowfall begins.

And… we just powered up the new solar system. 10,000 watts of solar, feeding into the grid. Though, quite a bit less than that at this very moment, because it’s snowing hard and the snow is piling up. So, I got the project (mostly) completed just in the nick of time. I still have some inside work to do with the water heater (post: “An Efficiency No-Brainer“), and a few odds and ends here and there, but the bulk of it is finished. Some photos of “Phase Two”—


Thirty-six Enphase micro-inverters. Each panel gets its own inverter, and feeds 220-volt power into a trunk line, and from there through a meter and into our main sub-panel.



Step one– putting up the rails.


The rails are held to the roof with brackets that are attached with 3 1/2- inch lag screws. I got lucky with the purlin spacing, and only had to add one, the new wood is visible here. I also had to add an extra block of wood under each bracket to give the bracket screws enough material to grab onto. Each rail had 11 brackets, so that meant 66 blocks that had to be added. It took a while; I was glad when I had them all in.


DSCN1256 (2)

Our interim power solution while we were between systems, two Honda 2000-watt ultra-quiet generators, tied with a patch-cord to combine their outputs. The 30-amp plug is tied through a transfer switch inside to the load center in the house. Our biggest load is the well pump, which appeared to draw 2300 watts. One generator is mine, the other is my neighbor’s; he was gracious enough to let us borrow it for a few weeks. This setup proved quite flexible– we could run one generator, or both, or one and not the other, depending on how many loads we wanted on. The generators also idle way down in “eco” mode; better than listening to a large generator yammering away.


Midway through the roof work, Green Mountain Power came and pulled the power in. Here’s the transformer cabinet in front of the barn.



The combiner box. Each row of 12 panels feeds a trunk line that ends up at one of these 220-volt breakers. From here the combined power of all the panels feeds into the solar meter.



It turned out to be easier to bolt up all the invertors before the panels. High winds were hampering my panel installation efforts, anyway.



The “Sola-deck” box flashed into the roof. The three trunk lines terminate here, and are tied to THHN wire to go through the conduit and down to the combiner box. It is also possible to use the Sola-deck box as the combiner, but we didn’t wire it that way.


Finally, a nice day to install panels last Sunday. I worked non-stop and got nearly all of them up in one day. I made a jig to hold each bottom panel while I connected it. There’s probably a better way, but I was working by myself.

So, the bulk of the project done. Each inverter reports data to the internet; I’ll keep track of the input. If all goes well, we’ll be powering the house and the cars and still have some left over. Material for a future post…