Bam! My solar is now fully operational!
This morning, the electrical inspector stopped by. I pulled off the cover of the MidNite Solar AC Disconnect Box for him to look inside. That was about it. VERY simple inspection for the solar. I also had a sample of the Enphase trunk cabling to show him. After that, he took a look at the rest of the general garage wiring. So, I now have Final Electrical Inspection for both the solar AND the whole garage!
Not too much later, I got a phone call from the power utility. Last week, I sent an e-mail saying that I would be doing the wiring this past Friday, and installing the panels on Monday (which was yesterday.) After the installation yesterday, I sent another e-mail saying the installation was complete. This morning, Greg, the utility representative asked if they could come over to perform the Anti-Islanding Test. YES, PLEASE!
Anti-islanding is an important feature of grid-interactive solar inverters. The inverters create 240V AC electricity in sync with the grid. If I consume LESS power than is created from the solar panels, the excess power flows out over the grid to my neighbors. In the event of a blackout, we would NOT want current to flow back to the grid! An unexpected second source of power would run backwards through transformers to even higher voltage. An electrician, working to FIX the blackout could come in contact with LIVE conductors that he would have expected to be dead because he disconnected the other end! High-voltage power has the potential to be lethal, so the Anti-Islanding is an important test. The upside is that it’s also a safety feature built right in to any modern inverter designed for grid-tie solar.
The point is, it’s important, and the utility wants to test the automatic shut-down feature of the inverters before giving me permission to connect to their grid.
Twenty minutes later, Greg, an electrical engineer, and other utility employee hopped out of a van in my driveway.
Their first question was “Where is your big inverter?”. I had to explain that there WAS not single central inverter for the solar. They were used to seeing a big box on the wall with a display that always tells the power output in real time. I explained with my micro-inverter system just uses a simple connection to one breaker. There is no central box with display. I also have a smart-phone and web interface for the micro-inverters, although those wouldn’t be appropriate for the split-second measurements for the anti-islanding testing.
I suggested they simply throw an ammeter on the one of the hot wires. We turned on the power – both the 30A breaker and the outside AC Disconnect. The inverters will NOT produce power for a full five minutes after connection to the grid.
In the mean time, the engineer unscrewed the cover for the pulling body on the inside of the garage, pulled out a hot wire, and clamped the ammeter to it. I explained a little more about how my system worked, and showed some sample components to the utility employees as well.
Once the five minutes was up, we could see power starting to flow on the ammeter display. Greg had out his stop watch while the engineer flipped off the main breaker to simulate a blackout. Instantly, power stopped from the micro-inverters. The testing was quick and simple, but required to make sure that the system will always be safe for line workers.
After that, the guys pointed out to me how my reprogrammed utility meter will now show both energy consumed AND energy produced. My digital meter has an underscore symbol at the bottom of the display. This takes the place of the black mark on the disc of the old mechanical meters. When it animates to the right, I’m using power, when it animates to the left, I’m producing power. In another part of the display, there is an arrow. When it’s a left arrow, I’m producing, when it’s a right arrow, I’m consuming. I also showed the utility folks a sample piece of my roofing and the S-5 clamps.
So, that’s that! My roof is now producing power!
I set up my software metering so, please visit the link: https://enlighten.enphaseenergy.com/pv/public_systems/PqBp1213167/overview (Please ignore the extra two solar panels shown in the display. Those were two that I experimented with earlier and am trying to figure out how to delete!)
In some ways, it’s completely anti-climactic. There were no sparks or noise when flipping the switch. There’s no whir of a wind-turbine or the putt-putt-putt and fumes of a gasoline generator. The solar panels just sit there, quietly producing energy. Very modest, those solar panels, working so hard, yet looking like they are sitting there not doing a thing!
Until next time, stay charged up!
-Ben
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Congrats! Nice system. Nice work. Let the sun shine and the wind blow.