Here are a few pictures of the construction
We started this project by running the wires. In this case, the power requirement is for 240V at 8Amps max. We also had a distance of 120 feet from the outside breaker box to the panels. We ran a 10gauge 4-wire (black/red/white/ground) and a dedicated 8guage bare copper ground wire. The steel roof gave us a built-in conduit by running the wires down the ridge cap. In this picture, Danny is pushing the pair of wires down a 30ft section of the ridge cap and Sean is ensuring that the excess wire does not get cut on the edge of the steel roofing.
Here is a detail of the Solar Power Disconnect. The National Electric Code (NEC) requires that the solar feed have a "air gap disconnect" that is located near the main breaker. This air conditioner disconnect also has fuses. Note the bare copper #8 wire going all the way to the man ground bar.
Another NEC requirement is that the Solar Disconnect is labeled. The stickers for the disconnect can be ordered through www.AltEstore.com. NOTE: this picture does not reflect the new meter. After the installation of the disconnect, and before the panels are installed, the Inspector is to come out, and then the Electric Company will install the new meter. The new meter has electronics that allows for the NetMetering (meter runs backwards) http://www.flatheadelectric.com/energy/netmeter.html.
From the meter, the power runs up a conduit into the soffit and down the ridge cap. This is the North side of the house and gets no sun.
The roof was an interesting issue. Initially, I planned to do all the work myself. After running the electrical out to the panel roof area, I determined that the roof layout was not going to work. The original roofer had put the screws through the TOP of the corrugated steel roofing into the joists. Each joist was directly under the top of the steel (not down flat). Now we knew why all the screws were all coming up ever year! This project, just got more expensive... we put a new roof on this area to shift the steel over so the steel would be flat over the joist. It was clear that we did not have the talent for that effort, so we hired Trendy Construction to put on the new roof and help with installing the panels. The lift was invaluable for putting those 50lb panels up there!
You can also see the shadow issue... 2 trees were cut after this. It is a bit of a funny thing, to save CO2 emissions, we cut down 2 trees to be burned for heat.
There are special connectors for "standing seam" roofs. But for "trapezoidal" roofs, there are no special brackets. We drilled a hole through the roofing so it would not be distorted when we drove the 4.5inch screw into the joist. 50year silicon calk was put into the hole, under the bracket, and around the bracket after seating the bracket onto the roof. You can see the line used to keep the brackets level and the rail attached. We used Iron Rail brand from http://www.wholesalesolar.com/.
The snow load for this part of Montana is 68 lbs/sqft. The slope for this roof is 33 degrees. We over-built the rail for even more load. We don't worry about wind here, but the snow load could be significant.
The panels come to within a foot of the ridge of the roof. This should reduce the amount of snow that gets above the panel and applies pressure to the brackets.
Here is a picture of the wiring coming from the roof ridge cap to the panels. There is a metal junction box under the cap that connects the 4-wire 240V to the Enphase cable (shown in black). Also note the bare copper #8 ground, that roof should be grounded now!
Here is a close up of the panels mounted. The gap between panels is about 1/4".
This is an odd view from the top of the panel looking down onto the rail (roof steel is at the bottom, panel on the top). You can see the electrical junction box from the panel and the extra wire coiled up. The MC4 connectors go from here to the inverter. You can see that we mounted the inverter just to the right so the wire would not interfere with the cooling of the inverter. All the wires are off the roof so snow and ice can slide under the rails without pulling on the cables. Each rail joint has ground wire jumpers because we are using the rail as the common ground for the system.
This view is from the end of the entire row of panels. You can see the steel roof and all the panels down the top rail. Each inverter is attached to the rail and grounded with the bare copper wire. The connectors are all tied up to ensure snow and ice don't pull them down. Each inverter has a great air gap around it to enhance the heat dissipation and air flow.
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This is a close up of the bottom rail and the frame of the solar panel. You can see a screw in the rail sticking through one of the elongated holes in the frame without a nut.
A trick for mounting panels... on the lower rail, purchase some stainless screws that stick up about 1/2" and fit in the rail slot. Every panel has holes in the frame that can be used to mount the panel to the rail. They are impossible to use for roof mounts because you can't reach them easily, but the holes make great targets for some screws in the rails. When you put the panel on the rails initially, they are heavy and hard to manage. Just put the panel on the 2 screws that you have sticking up to stabilize the panel while you scoot it around and get it square. The holes in the frame are elongated so they can be rotated a bit for perfect fit. This also helps when you are under the panel making the final MC4 connections and tying up the wires. Just tilt up the panel on the bottom screws and don't worry about the panel sliding off the roof! Don't worry about the screws, they will just stay there without a nut, the top clips will be enough to hold the panel down.
We had one of the micro inverters stop resetting properly about 10% of the time after about a week. Enphase sent via Fed-Ex a new replacement free of charge and we were back on the roof. That trick with the screws in the bottom really paid off, here I am replacing the inverter. (we did hook a rope to the panel, just in case it got bumped, but it held by those 2 screws perfectly)