Tuesday, December 16, 2014


We joined the solar revolution! This was a long process. We thought about it for years, first got some quotes last year, and got serious about it this July. We signed a contract with Occidental Power in August, and construction ran from mid-November through the beginning of December. Then, today, we got our permission to operate letter from PG&E, and now we're live!

Day 1 (November 14): Occidental Power installed the mounts for the solar array during the reroofing.

Day 2 (November 20): A couple of days after the roofers finished up, Occidental mounted the inverter on our basement wall. That's an SMA Sunny Boy 3800TL-US, if you're curious.

Day 3 (November 21): Occidental got the rails up on the mounts.

Getting things up to our roof isn't easy. Here's the 30 ft ladder Occidental used for some stuff. Or most of it—I couldn't quite get the bottom few feet in frame.

Day 4 (November 24): The solar panels went up onto the roof.

The rails keep the panels above the roof, allowing for some airflow. That's good, because the heat from the roof reduces performance. The airflow allowed by the rails doesn't fully counter this effect, but it mitigates the loss.

Day 5 (November 25): The installers ran electrical conduit from the panels to the inverter. This is the top of the roof, from our backyard. They routed the conduit fairly inconspicuously.

This is the east side of the house, viewed from the back of the house. The conduit comes down along the side of the house, again pretty inconspicuously, and enters the basement next to an existing hose bibb.

The conduit comes into the basement at about ceiling level, and then is routed along a wall, behind our dryer, washer, water boiler and furnace, ending at the inverter.

Day 6 (November 26): The inverter was actually wired up, including the short conduit run to the electrical panel.

Note the "CAUTION SOLAR CIRCUIT" sticker on the lower conduit, which is the one from the panels to the inverter. I assume that is because even if you use the DC disconnect on the inverter (the black knob on the bottom-left of the inverter), the connection from the solar panels to the inverter is still live.

They also tested the array, and the array was pumping out around 1350 watts...

...which was enough to run our meter backwards.

(Because we didn't yet have a "permission to operate" letter from PG&E yet, we couldn't leave the array online, but it was working!)

The installers also needed to supplement the grounding of our electrical panel. Pre-solar, it was grounded to our water pipes, and that was it. Which was fine whenever the panel was last dealt with. But code now requires two grounding rods in addition to the water pipe ground cable, and we needed to be up to code to pass inspection. That involved pounding 10-foot-long copper grounding rods into the, well, ground. These pics are of one grounding rod that is a few feet in, and another that is all the way in the ground.

They used a big mallet to get the rods started, and then turned to a rotary hammer...

...but just in case, they also had a jack hammer.

Day 7 (December 1): Next steps were connecting the panel ground to the new grounding rods, and getting the whole thing inspected by the City.

In the top-right of this picture, you can see the old ground cable, from our water pipes. This used to go to the panel, but now is bonded to the new ground cable, which is black.

That new cable runs through the basement ceiling rafters to the front of the house...

...to the grounding rod outside...

...which is bonded to the second grounding rod outside via a short conduit.

After all that, the City initially did not sign off on the work, but did approve everything a couple of days later, once the inspector had reviewed pictures of a few adjustments made at his direction (like bonding our gas line to the ground).

Day 8 (December 2): The installers finished up by installing our secure power supply and a data card for the inverter.

The secure power supply (see the switch & outlet in the pic below) is a cool feature that lets us get power from our array during daylight hours in the event the grid goes down (we can't power the house when the grid is down, but we can power this single outlet, so we can charge phones or electronic child placating devices—or we could even use a long extension cord to power our fridge while the sun is up in the event of a lengthy outage, I suppose). If the power goes out, we can flip the SPS switch, and then after a brief startup sequence we can start drawing power (up to 1500 watts, assuming there is enough sun) from the SPS power outlet.

You can also see an ethernet cord snaking out of the bottom-right of the inverter, which is from the data card. That goes to our router, and allows us to track how our panels are doing via the "Sunny Portal" website that is powered by SMA America, the maker of our inverter.

Day 9 (December 12): Occidental came back to go over how everything works with me.

Day 10 (December 16): We got our letter from PG&E granting us permission to operate! We flipped the switch, and now we're live!

No comments:

Post a Comment