Don't expect this to be anything like ordering a bowl from Create & Barrel. First, most companies selling PV are used to dealing with electrical contractors, and electrical supply companies, not individual consumers, like you and me. Don't expect them to take a credit card, they may not. And since you aren't in any position to fill out a typical credit application with them like business would, you may be stuck offering them a personal check with the understanding they will not ship for 10 days until they are sure the check has cleared, or they may want a direct bank transfer.
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The shipping will be by freight, not Fed Ex or UPS. Expect it to take a while, and expect the freight company to expect you to either pick it up at their dock or have a dock and forklift ready to take it off their truck. Since the modules will be delivered on one or more pallets and weigh 1000 pounds, don't even think of unloading them by hand. You can probably pay extra to the local freight forwarder to deliver them and unload them, but discuss that in advance. You really don't want an 18 wheeler showing up in front of your driveway with 2000 pounds of modules on pallets and no way to get them off. |
| Unpack all the modules, as soon as possible, even though it may seem like an unnecessary hassle. You need to find out if any of the modules were broken in transit. They are, after all, glass. And glass breaks. One of the modules I received was broken and had to be replaced. That's a whole nother hassle dealing with the freight company's insurance company. Expect it to take 90 days for the claim to be settled before you finally get repaid for the replacement module you ordered and probably had to pay for immediately. |  |
The track goes directly onto the roof, and then the photovoltaic modules go on top of the track. The track I chose was SolarMount by UniRac. For my simple runs of just a few panels, their "Light" product line was sufficient and economical.
| Don't even think of installing the rack until you have a plan on paper and you've laid out that plan completely on your roof and it works. Step one is lag bolting the "L" brackets to your roof. Assuming you have a standard composition roof, the bracket mounts just like you would anything else bolt onto your roof. Find the joist, drill a hole for the lag bolt and be sure you hit the joist, use asphalt roofing sealer to fill the hole, smear it under the bracket, and onto the lag bolt too. Drive in the lag (with a flat washer) and you should see the asphalt sealer ooze out all the way around the bracket base and also out the lag bolt hole. |
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When all the "L" brackets are down, you can bolt the rail to the brackets. It is that simple. Just put all the track up the same way. And be careful moving around steep roofs with all the track installed. Don't trip.
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Don't freak out when you drill a hole and miss the joist. It does happen. It will happen. That extra hole in your roof isn't going to be a leak, we just need to patch it. If you just missed your joist by a half inch, then drill the correct hole, fill the extra hole with asphalt roofing sealer, and bolt down your "L" bracket. The base of the bracket will completely cover the wrong hole and with all the asphalt sealer you will be water tight. Yea.
| If you missed by so much the "L" bracket base won't cover the wrong hole, you'd just need to patch the roof with a small scrap of shingle. The closer the color match to your roof the better, but for my picture at right I used a shingle scrap that was just a bit lighter than my roof so you can see it. Just fill the wrong hole with asphalt sealer, cut the scrap to size, and slide it under the row of shingles immediately above the hole. A little bit more asphalt sealer will stick the whole mess together and you will be water tight. |  |
The term grounding is often used mistakenly when bonding is actually intended. Grounding metal parts to the earth in premises wiring is only useful to provide a path for lightning, shunting high-frequency noise, or reducing static discharge; Bonding all metal parts together and then to the system winding (typically to the X0 terminal of a transformer) is done to provide a low-impedance path to the source (system) to facilitate the opening of the circuit-protection device to remove dangerous voltage on metal parts. In addition, bonding the system to metal parts (typically to the X0 terminal of a transformer) stabilizes the system voltage to the metal parts and it provides a zero system reference (to the metal parts).
Our local building code is very specific for grid-tied systems: every track segment must be bonded and every module must be bonded. Use a good lug rated for copper and aluminum, attach them to each rail segment and then run your bare copper wire to connect everything. The bonding wire must be terminated either at your main panel, or at the inverter, if the invert provides a termination lug for equipment ground, as is provided on my Sunny Boy inverter. (I sized the conductor based on my 30 amp circuit breaker so I used 10 gauge wire, but during final inspection I was told exposed copper on the roof had to be at least 8 gauge, regardless of the circuit capacity.)
And while we're on the subject of track bonding, don't forget if you butt-splice pieces of track you need to bond each section independently. You can't just rely on the physical connection of the splice to bond them.
The modules are easy to install, just position them correctly on the track and bolt down the clips.
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Clamps between modules
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Clamps at end of modules
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Just like the rails, bond each module to your bonding conductor. Most modules don't have a good lug so you will probably want to install your own lugs, just like you did for the rails.
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Page lasted updated April 06, 2008
