Insulation, Doors, and Solar Cables

by Ben N on March 11, 2017


Two weeks ago, I got the bid from the insulation company. Because of their economy of scale, and having a nice box truck and other equipment handy, the insulation company can insulate my garage for not a whole lot more than if I went to the big box home improvement store and bought insulation to do it myself.

Because the “Loft” upstairs of the garage is basically the attic, I’m limited in how much space I have for insulation up there. However, in the FLOOR of the loft, the bottom cord of the truss is a 2×10. I’ll be able to put in almost 10 inches of blown insulation in there to keep the heat in the downstairs. Yesterday, I called them back up and put in the order to proceed with the installation. The insulators will be out this next week. It will probably take MORE than one day, but not by a whole lot. Apparently, these guys are pretty quick.

As much as I LOVE the idea of a “super-insulated” garage, one of the big practicalities is simply the budget, along with physical space. I’m also only planning on heating the garage to about the lowest level I can. The lower the temperature difference between the outside and inside, the less insulation needed. Super-insulating might be nice, but does’t make sense if all my heat leaves when I open the garage door to move a car in or out! That said, I’m looking through all the nooks, crannies, and penetrations and sealing them with expanding foam before the insulators get here.


I also stopped by the garage door installation company – Hartland Overhead Door. It’s one that my father’s construction business always used, and it happens that I know the two sons who now run that family business from high school. I got a quote for two doors of the 2″ thick urethane-foam filled variety. The price was identical to a 2″ foam door at the big box store, except that with the full-service garage door company, it includes installation!

Before I left, one of the owners, Joe, stopped back in, so I got to say “Hi” to him. I explained what I’m trying to do with the solar panels and how I’d like to integrate some sort of “sunny winter day” glazing into the garage. (Perhaps something like this – BuildItSolar Link) On the demo in their shop, Joe showed me a pull-down screen door for garages. It was a very simple design with one vertical piece of track, one horizontal, and a rigid aluminum frame that holds the screen. I pondered the possibility of getting something like that, only without the screen, and installing twin-wall polycarbonate instead.

I believe that this is the screen that I saw. I didn’t ask about price while I was at Hartland Overhead Door. Later, I tried finding an online retailer to check pricing. It was nearly $1,000 for the screen door, no matter which size! Yipes! The design did look simple, so maybe I can make my own from scratch?

Lastly, a friend of mine is sending me a couple of USED micro-inverters. He found them at an electronics salvage yard. We have no idea if they even work or not, but they were CHEAP!

I purchased a “two-drop” section of Enphase Engage cable. This is the special cable that Enphase’s micro-inverters plug right in to. I bought this short piece so that I could test the used inverters, check the cable against what other components I might need to use with it, and in the end, have it for demo’s, presentations, and as a teaching sample.


After I picked up the cable, I stopped at the Home Improvement store to check out the electric department so I could find the right connector and outdoor rated boxes. I located a 1/2″ watertight cord connector and tested the Engage cable with it. Sure enough, I could just squeeze the cable through the inside of the connector. (The outside diameter of the cable itself is larger than 3/8″ but smaller than 1/2″.)

Next, I tried finding an appropriate weatherproof box for that connector to screw in to. I couldn’t find the right type of box at all, until I finally located an employee, and he showed me that what I was looking for was actually the next aisle over. (I THOUGHT I was in the last aisle of the department…)
Over there, I found both metal and plastic NEMA3R rated boxes. They are sorted by “Number of Gangs” and number of holes. There is also standard depth and extra deep boxes. I found it interesting that a one-gang box was cheaper than a 2-gang, but that the COVER for the one-gang cost more! Go figure.
I ended up buying a one-gang, 3-hole, standard box (in plastic) with the matching lid. This will act as a junction box between the specialty micro-inverter cabling and standard 12 ga wiring inside of conduit.

IMG_3503Back at home, I wired up the cable through the watertight connector, into the box, and connected the lid. It all looks nice and solid. From this, I’ll be able to run some wiring to this junction box to build a test-rig for the micro-inverters.

It’s sunny today (but COLD!) so it would be an ideal time for testing solar inverters. Too bad I don’t have them yet!

I’ll be spending the rest of the day dragging ladders and materials out of the garage and stacking them outside. I also need to do anything else that I can think of that needs to be done BEFORE the insulation crew is here. For example, I might want to fully document where all the wiring is while I can still see it!

I’ll be very busy this next week too, but getting the insulation in will feel like a big step forward!

Until Next Time, Stay Charged-Up!

PS: I think I forgot to mention the “Man Door”. We got that in last weekend. It’s a vinyl door filled with urethane foam. I installed just a plain inexpensive lock-set on it. I might eventually be adding a “smart-lock” or a push-button deadbolt so that I can keep the garage locked all the time, but still easily go in and out, without having to dig through my whole keychain every time.

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