After completing a 2nd story addition it was time to install the photovoltaic solar panel system that I was wanting to for many years but because of the plans for the 2nd story addition and new roof was delayed.
This description of the process and technique I used should not be considered instructions. Solar panel installation in california PG&E requires a lot of work with electricity and electrical wiring and work on the roof and should only be performed by licensed electricians and contractors unless you are a very knowledgeable and experienced DIY’er.
Step #1 -Figure out how big of a system I need. When I added 900 square feet to my home I switched to all LED bulbs and we have never had AC. Our water heater, dryer and furnace are all natural gas so the only items we use electricity for is lighting and the refrigerator and the stove/oven. Prior to the remodel our bill was an average of $80 a month – after the remodel, with the LED bulbs, our electric bill is down to $40 a month! It is very hard to justify spending $10k plus to save $500 a year! At $40 a month and $.20 per kwh which is a typical rate in California for power from PG&E that equates to 200kwh per month or about 7kwh per day. In Northern California we have an average of 5 hours per day of solar generating time so that works out to needing a 1.4kw system to supply my current solar power needs. here is the chart i used
I decided on a 3.6kw system – more than double my current useage – as I plan to switch over to electric water heater, electric heaters and add air conditioning for the 2nd story.
Step #2 – Get quotes from a few solar panel installation companies to see if there was any savings for DIY’ing. I have heard that these solar panel companies buy panels and inverters in such large volumes and their workers are so good at the installation that the prices they charge are a great deal versus DIY. The solar companies I spoke to were reluctant to quote when they heard my current electricity bill was so low. The quote i did receive were $14000 and $16000. One company quoted a micro inverter system the other a central inverter system.
Step #3 – Then it came time to compare the DIY cost. I checked several websites and called several local companies and found ML Solar to be the most responsive and easy to work with. There are a variety of panel and inverter manufacturers to consider but since the payback is 5+ years I wanted to get panels and inverters from a reputable brand that would make a good product and stand behind their warranty. I picked a 310 watt LG solar panel and the enphase micro inverters. The panels, racks and inverters – total cost $6500. The cost for the wire, conduit, and other materials was another few hundred dollars. Total for DIY $7000 plus 3 days labor – or pay the solar company twice that..I decided to do DIY to save the $7k. There is a 30% rebate so the savings is closer to $4000 after rebates, etc.
Step #4 – get the permit. Cost for the permit was about $200. 11x 17 drawings are fine. I used the drawings from San Diego as a starting point, pasted in the details from LG and enphase and snap n rack websites. I had to add a note about the wire size – 8 AWG, the need for a base every 4ft for the snap n rack, and the lag screw embedded 2.5 inches into the roof rafter/truss. Took these to the city – paid my dollars and got the permit.
Step #4.5 – complete paper work with PG&E – The process was very simple for my house. PG&E has a lengthy application to complete and then a process to have it signed. No one from PG&E – to my knowledge- came to inspect the meter or installation. The entire process was conducted on line and was remarkably painless. Here is the link to apply for the residential solar net meeting hookup.
Step #5 – Put in the disconnect and start the conduit. I guess you can start from the top and work down or from the bottom and work your way up. need to ensure the conduit system protects the wires from the elements. I used metal conduit but the “next” time will use PVC. The disconnect is a D- Square unit that has 2 fuses. The fuses are not needed in the system design but it came with the disconnect so i bought a couple 20amp fuses for $2 at Home Depot. I purchased the disconnect on ebay for approximately $30. I am using micro inverters so there is AC 240 volts running through this disconnect from the inverters to the circuit breaker panel. A label needs to be applied to this disconnect. The city made it very clear to bond the conduit – so i purchased small bonding – bushings that fit on the end of the conduit to ensure they are grounded/bonded.
Step #6 – The conduit on the roof. All of these items were purchased from Home Depot except for the roof jacks. I bought those online due to the small diameter I needed to seal the conduit. Home Depot may have had them but I couldn’t find them. Bending the conduit and creating the little stand offs to secure the conduit above the roof was all pretty easy.
Took about 3 to 4 hours to put in all the rails and mounts, etc. etc. for my 12 panel system. Because of vents and the smaller 2nd story south facing roof I ended up putting the panels in 3 different groups. That required more conduit work but that is the only downside that I know of so far. The ends of the rail will be cut to length after the panels are in place. The manufacturer suggests placing a support every 8 feet of rail length – the city of Sunnyvale requires the supports every 4 feet. This picture to the right is BEFORE I was told about that different and installed the additional 6 supports. It goes a lot faster now that I am getting some practice!
Step #7 – Install the Snap n Rack rail mount system. No particular reason that I selected this system. It was recommended and seem to be widely used so that I felt confident it would work for my project. Installation was straight forward.
Step #8 – install the enphase inverters. This required very little effort. The inverters just clamp on the rails and the wiring harness all have plugs and just snap into each other. Super easy. On one end cap the wires with a cap that enphase sells. On the other end wire it into the junction box through a water tight fitting that Home Depot sells. Easy:). It may have taken an hour to install all of the inverters and wire them up. The racks also need to be grounded as well. The ground wires are clamped to the racks and then attached to the conduit which is grounded to the grounding rod near the foundation.
Step #9 – install panels. The panels are easy to place and clamp down. I had some help with panels – they are not very heavy, just 40 pounds each, but they are large and I wanted an extra set hands of to avoid a panel sliding off the roof and damaging the gutter, the panel or falling off the roof and damaging something on the ground. The panels come ready to plug into the inverters and the clamps that hold them to the rail are simple to use. Just need a wrench.
Step #10 – test the system. The system has two switches. The lockable disconnect switch and the 240volt 20amp breakers in the breaker box for the house. to connect the solar panels to the house and PG&E use a circuit breaker that is suitable for back feeding – most are unless they specifically say they are not or if the legs are labeled “load” “line” etc. The GFI requirement is meet by the inverters that have built in GFI. I looked for different system that would monitor the power from the panels and inverters and the “best” I could find – value wise- was the envoy from enphase. It is expensive $475 for a plastic box and an LCD and a little circuit board but it communicates to the inverters and via your wifi or ethernet internet connection to some dbase somewhere that provides a verety of reports. The systems works well – is no hassle to install. It takes hours to establish communications with all the inverters so patience is helpful