Photovoltaic Tutorial:

Step-By-Step Guide to Going Solar

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13. Test and inspect your new system.

Before asking a building inspector to visit your home and approve your solar installation, you'll have to test the system and inspect it yourself. Basically, all the the checks and tests the inspector performs, you'll do yourself. In addition, you don't want to energy your system all at once, since incorrect wiring and other problems could potentially do some damage. That's why an installer must verify open-circuit voltages, visually inspect connections, and then turn on each section of the circuit, one at a time.

The first step, of course, is a simple visual inspection, Here you or your contractor will verify that:

The process of starting up a solar power system for the first time is called commissioning. The first step involves completing your component connections from the array to the inverter. As with any electrical circuit, you should start farthest from the power source and work back toward it.

In the case of a solar electric system with no battery bank, you'll work backwards from the inverter's input side to the array, and then backwards from the inverter output side to the main service panel. One important caviat to this procedure is that on the DC side of the circuit, your last connection CANNOT be connecting the home runs. You must do that BEFORE switching on the DC disconnect. That's because energizing any circuit should always be done with a switch, not a manual connection. You certainly don't want a problem in the circuit to present itself while you're holding the connection point directly in front of your face! If there's going to be fireworks, they should happen inside an electrical enclosure.

And since none of us wants to see fireworks, the next step is to use your multimeter to measure voltages around the circuit. Needless to say, you'll have to wait until the sun is shining.

The measurements and other checks you'll perform include the following:

Once the DC side of the circuit is tested and the readings accurate, you can flip the DC disconnect switch to "On" and take some more measurements. If everything looks good, you can turn on the inverter and see how it responds.

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Here's a list of several inspection and testing checklists to give you an idea of what inspectors will be looking for. You can also download the NABCEP Inspector Guidelines or the IREC Field Inspection Guidelines to help guide you through the process.

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Next, you or your contractor should measure voltages along the AC circuit. This task begins with the inverter, AC disconnect, and main panel DP breaker all in the "Off" position.

If the voltage measurements conform to your expectations, you can switch on the inverter and give it time to warm up. (It can take up to 30 minutes.) Then take voltage measurements between the output side and the AC disconnect. If the readings looks good, turn on the AC disconnect and take readings on the output side of that device. If all goes well, you'll be ready to flip the DP breaker on your main panel. At this point, the inverter display should provided you with some hard data about the array power output. If an error message appears, especially one that indicates a ground fault, you'll have to shut down the system and troubleshoot the problem.

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As stated previously, only a licensed electrician, certified NABCEP installer or other qualified person should install and test the PV breaker at the main panel, since the potential for injury or electrocution is ever-present. Even when you power off the main circuit breakers in the panel, electricity continues to flow into the bus bar from the grid. An electrician or certified installer is trained in all the precautions necessary to avoid an arc blast, electrocution, and all other dangers imminent when coming in contact with 240 volts of deadly energy. So let that person take the risk instead of you.

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One thing to keep in mind about an inverter is that its circuitry includes capacitors that store electricity and slowly release it. That means waiting a couple minutes after turning the unit off before you perform any tests or adjustments.

After you've resolved any problems and perform a successful commissioning of your new solar electric system, you can contact the building inspector and schedule a visit. Don't leave the system running, however. You won't get any credit for the kilowatt hours produced until the utility company signs off on the installation and inserts the necessary metering device that will counts the solar kilowatt hours your array produces.

The video below briefly illustrates how a commissioning is performed:

Create a homeowner user's manual

Most code authorities require contractors to prepare a "User's Guide" for each PV system they install. Most solar companies have this literature pre-printed and ready to go, but if it's your project, you'll have to cobble together the information yourself. It's not that difficult a task. Start by transferring most of the material from your construction bible into a new binder you'll furnish to the homeowner, even if that person is you. After all, the building inspector may ask to look at it during the site visit.

Try to assemble the material in a coherent manner that makes sense to an everyday housewife or house-husband. (Even a teenager should be able to figure out the basics, since she or he may be the only home in an emergency.) Beside the product guides, warranties and permit application materials, you'll want to prepare a few additional documents, such as:

Contact your utility company

Once an installation has been tested and approved by the local building inspector, you can call your utility company to schedule an interconnection visit. Investor-owned utilities like PG&E are usually in no hurry to give up revenues, so their process can take awhile to complete. In some parts of the country, you may be waiting three months or more, so be patient.

The utility company will have its own inspection procedure and forms for you to fill out. Moreover, if your submittal derivates in any way from their instructions, or if the circuit itself is different from what the utility company wants to see, then your interconnection request may be denied. At this point, you'll have to correct the mistakes, reschedule a second visit, and maybe wait another three months.

Solar companies will likely have an edge over DIY installers and small contractors when it comes to interconnection. At any rate, when the great day finally comes and the utility representative inserts the all-important metering device, you can flip on your new solar power system and start making some money.

Apply for your tax credits and rebates ASAP

Don't forget to promptly follow up with the paperwork required to collect any rebate offer, the federal tax credit, loan payments, or any other incentives associated with your solar power system. Many incentives have a time limit for filing, so pay close attention to those deadlines.

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