All the Gear
While the ground dries out from the big rain, Jerry and I take a hard look at all the gear shipped to us by GoGreenSolar.com, reading manuals and lining it all up in order to plan the installation.
The oval device top left is the Envoy Communications Gateway that sends data from all the microinverters to the Enlighten website where we can monitor the performance of the solar array over time.
A maximum of 15 Enphase 190 watt inverters can be installed on a single circuit, so we divide the array into two circuits of 15 inverters each. A small junction box begins each circuit, They connect to the two 15 amp circuit breakers that will go into the combiner box (with the big red lever in the photo) and to the cable that goes to our home electrical system. We have a 240 volt subpanel for our well and water equipment in the nearby shed, which in turn connects through a cable to the Carroll Electric meter in the field east of our home. The gear includes a box of grounding wire lug nuts, a lightning arrestor and a lockable disconnect switch required by Carroll Electric to be mounted on the outside of the shed.
Where’s the Electrician?
About this time I realize I should get an electrician involved in the project. Because I had completely wired a house a few decades ago, I thought I could get by with a consultation, and then at the end an inspection. Wrong. Mike and Faith tell me they are happy with master electrician Lyle Pinkley who installed their system recently, so I make an appointment. Lyle and his assistant review everything and give me a list of things to purchase at Maverick Supply, plus another list of things to return to GoGreenSolar.com. He saves me $360 even after restocking fees of 20%. Well, minus the much smaller cost of the replacements from Maverick. I’ll need to go over all that later when we get to financial details. So let that be a lesson to you: get your electrician involved at the beginning. I know this is obvious to most of you.
Finally, on Monday afternoon October 7, Jerry joins me in beginning the installation. We start with the inverters which must be installed first since they will be covered by the solar panels. The Enphase 190 watt inverters have long connecting cables that allow all the inverters in a circuit to be connected in series together. The more powerful Enphase 215 watt inverters require a trunk cable to which the inverters are connected, an additional expensive I saved by using the older cheaper and less powerful inverters. In a later post we’ll look at the tradeoff details of this choice that saved me $1,600.
Here Jerry is bolting on the first inverter. You can see the lug nut at the bottom of the mounting plate where the copper grounding wire is to be attached. A single strand of 6 gage bare copper wire must connect every inverter, solar panel and mounting rail to an 8’ copper clad ground rod driven into the ground.
We are so excited to see what it all looks like, so to test our approach, we mount the first column of panels. It’s a total thrill to see them there at last. Wow! Alece is thrilled too.
That evening while looking at the installation manual, I realize the inverters’ longer connecting pigtails are pointing up, rather than down toward the circuit’s junction box as required. So the next morning I have to unbolt and remove the three solar panels, disconnect the grounding cable, remove the inverters and reattach them to the opposite mounting rail, reconnect the grounding wire and install the three panels again. Oh well.
Another tricky step is getting all the mounting rails spaced evenly, and the bottom end-clamps set to insure the whole array will be square. There is head scratching, wheel spinning and some frustration as we work this out. I’ve come away with ideas about how to do this better which I’ll share in a latter post.
We install the rest of the inverters, running the ground wire across each mounting plate, and on up and down the rails leaving enough wire to attach to each panel and rail. Then we tuck the wire under the grounding nut on each inverter and tighten. We have to drill holes in the solar panel frames and mounting rails for the ground wire lug nuts in our shipment.
On Wednesday, like an old-fashion barn-raising, David, Jerry, Carl, Mike and Faith come to look at the ground mount system and how its all coming along. Together we work out the alignment strategy and begin installing in earnest. David and I hustle placing the mounting hardware to keep ahead of Jerry as he carries one panel after another to the array.
Lyle and his assistant arrive and begin the electrical installation. Wow, its all coming together.
In each column, three panels are placed over two parallel mounting rails. Two end-clamps, one for each rail, anchor the bottom of the first panel, then four mid-clamps anchor the middle panel to the bottom and top panels, and finally two more end-clamps anchor the top panel at the top. Here, Jerry is tightening the mid-clamp between the second and third panels. He uses a socket nut as a spacer to keep the columns of panels spaced evenly one inch apart.
We finish laying out the first two rows and David tightens the mid-clamps.
Now, how to get those panels up to that third row? Hmmm.
Jerry just grabs a panel and reaches it up across the front while David (on a ladder) and I help set it in place and finger tighten the clamps. Just do it! Wish I had a photo of that process. It is like, woosh, and before you know it there it all is: 30 solar panels ready to harvest the sun. Amazing. Beautiful.
Below, the first inverter of the second circuit ties into a junction box with a cable you can see going to the left off to the combiner box at the beginning of the first circuit at the east end of the array. Our shipment included a connection cable for each circuit that connects to the long pigtail of the first inverter you see here. The other end has prestripped wires you see in the right side of the junction box. I’m sure Lyle could have simply cut the connector off the last pigtail and stripped the wires himself, saving me the cost of the two connecting cables.
Below is the $25 combiner box Lyle got to replace the $191 box (with the red lever) sent by GoGreenSolar.com, where the two 15 amp breakers are to be installed to protect each circuit. The orange electrical cable goes down through the conduit, along the trench and up into the disconnect switch on the wall of the shed.
Below, Lyle installs the lockable disconnect switch required by Carroll Electric. The cable connects with the subpanel inside the shed and from there to the Carroll Electric grid.
We connected the inverters in series to each other as we installed them, but there is a serious warning to never connect solar panels while the sun is on them generating power, which can short across the connections damaging them. I decided not to connect the panels that evening since I hadn’t heard all week from Carroll Electric and had read they didn’t want us to connect to the grid until they had tested and installed the grid-tie meter.
Thursday morning, Jerry called to find out what kind of power we were generating. So disappointed he was that I hadn’t connected the panels that I decided to do that after sunset.
So next morning we are packing for our two week trip out of town when we get a call from Carroll Electric explaining the relevant person has been out of the office all week. When he realized I was ready to connect with application in hand, and had been trying to reach them all week, he said he would try to get someone over right away. They really came through.
On Friday afternoon, October 11, just before we left town, a Carroll Electric technician arrived to inspect and test the system. This guy was great: full of encouragement and interesting information. He was looking for the UL code on the inverters that said they meet the specifications for grid-tie systems that shut down when the grid is down. He took photos of the array and disconnect switch, tested the system and installed the grid-tie meter. He explained his testing is to be sure our solar array shuts down when Carroll Electric grid power is down, so that line workers are not harmed while making repairs. He also said there are other more effective safety measures that protect line workers from power generated by any grid-tie sources, and that making sure our system shuts down when the power is out is more to protect our own equipment which could be damaged by their other safety measures. Another point he made: a grid-tie system like ours helps them, because they have to buy more expensive power from suppliers when more capacity is needed.
The new meter records the net power generated by the array minus the power we use. When we use more power than we generate, for example at night, the meter records the kilowatt hours we use. When we generate more power than we use, the meter subtracts the extra kilowatt hours we produce: i.e. net metering. At the end of the billing year, the account is reset and we lose any surplus in kilowatt hours we might have produced. So at this time, there is no incentive to build a larger system than you use.
One additional interesting note: The technician said that connecting a generating system to the grid without the net metering meter in place results in any power you generate counting against you as additional kilowatt hours you are billed. This is done to thwart abusers who reverse their electric meters to avoid paying for some of their power.
Also note that the Carroll Electric representative I spoke to said they want your grid-tie application early, as you are beginning. This is different from what I had been told in a phone call to them before I even ordered our system — that I should contact them when I was close to being done — at least as I remember the call. This was confusing to me for another reason: the application calls for such things as the date of installation, the size of the system and the name and credentials of the person who did the installation. I had read everything about net-metering on both the Carroll Electric website and the website of the commission in Little Rock. There it said the utility has 30 days to respond to the application. So I am grateful to them for coming through at the last minute with such flying colors.
And thank you Jerry for that extra push to connect up all the panels Thursday evening. The result was more than 400 kilowatt hours generated while we were away.
And so, ladies and gentlemen, here it is: our beautiful solar array collecting the free energy of the sun. As Alece says, its a whole other experience when you turn on a light!