After interviewing various solar contractors, I selected ProVoltz of Campbell an "Elite SunPower dealer". In researching potential solar vendors, I spoke with Ash Wagner, an owner at ProVoltz; and in him I found a contractor that understood the solution I wanted. Mr. Wagner and his team provided competitive pricing and options. His knowledge and service commitment (per customer reviews) made my purchasing decision easy.
In the weeks before installation, Provoltz's staff communicated project expectations including:
- Planned installation duration of one week.
- System design showing the roof layout for the panels and conduit placement.
- City permitting, including permit copies for my records.
- PGE application processing and milestones for net metering.
The week before installation I received a phone call and emails advising of the work crew arrival schedule and other details. There were no surprises. When the crew arrived the first day and each day afterwards I was greeted before work commenced. At the end of the day, they told me when they were leaving and their expected start time for the next day.
On day one, the crew laid out their chalk lines for the mounting hardware. They confirmed panel locations and measurements for our 16 panel, 3.9 Kilowatt-hour system. Next came the roof mounting plates which were secured with lag screws into the roof rafters. Each plate supports a mounting bracket attached to racking rails that the panels are affixed to. Building codes and the layout design dictate mount plate locations.
Next came the racking rails. After making an initial "loose" fit installation to the brackets, the crew used strings to align the racking rails so that all panels have a uniform plane angle parallel to the roof. The rails for the most part, are installed with excess length. Doing so allows extra space to adjust the panel alignment, after which the excess racking is trimmed.
The wiring followed the racking installation. The wiring system includes a double electrical ground for safety. One ground is uninsulated #8 continuous solid copper wire that connects to the in-earth copper rod on the side of the house. The panel attachment points utilize this ground via a grounding washer called a "weeb", which stands for "Washer, Electrical Equipment Bonding" clip. The second ground is the green insulated wire connecting all the electrical components (panels/microinverters) to the service panel grounding bar. Seems like a lot of copper.
Since our system provides 240 vac alternating current from each panel, the panels are connected to a junction box by an electrical whip (cable) with two hot circuits, a common netural and the aforementioned grounding. As configured with 16 panels, each panels connects to both "hot" lines via separate circults and to separate 20-amp service panel circuit breakers.
While all this was going on, I was discussing with ProVoltz the options for conduit location. ProVoltz told me they preferred an interior installation, where they drill holes through the roof into the attic, then plumb either through the wall to the service panel or into the crawlspace to the service panel. Such a route would create a clean look with no exterior conduit. However, I preferred an exterior installation – perhaps not as pretty, but with fewer disadvantages. The three roof penetrations could cause roof leakage, and also this solution did not allow for easy future expansion. Going through the walls would be challenging; the in-wall wiring adjacent to my service panel would be difficult to avoid. Also, when we remodeled a few years ago and installed a new 200-amp service panel, I selected one with exterior connection points on the bottom. All these considerations led me to select an exterior conduit route, with a single penetration into a roof eave, where the conduit would be partially hidden from view.
With the wiring in place, a city electrical inspection was conducted. After the inspector’s approval, the wiring junction boxes and the service panel were closed.
Bring on the panels...