Before connecting a photovoltaic system to the grid

What about permits?

If you live in a community in which a homeowners association requires approval for a system, you or your PV provider may need to submit your plans. Gain approval from your homeowners association before you begin installing your PV system. Under the law in some states, you have the right to install a solar system on your home.

Most likely, you will need to obtain permits from your city or county department. You will probably need a building permit, an electrical permit, or both before installing a PV system. Typically, your PV provider will take care of this, rolling the price of the permits into the overall system price. However, in some cases, your PV provider may not know how much time or money will be involved in “pulling” a permit. If so, this task may be priced on a time-and-materials basis, particularly if additional drawings or calculations must be provided to the permitting agency. In any case, make sure the permitting costs and responsibilities are addressed at the start with your PV provider.

Code requirements for PV systems vary somewhat from one jurisdiction to the next, but most requirements are based on the National Electrical Code (NEC). The NEC has a special section, Article 690, that carefully spells out requirements for designing and installing safe, reliable, code-compliant PV systems. Because most local requirements are based on the NEC, your building inspector is likely to rely on Article 690 for guidance in determining whether your PV system has been properly designed and installed. If you are among the first people in your community to install a grid-connected PV system, your local building department may not have approved one of these systems. If this is the case, you and your PV provider can speed the process by working closely and cooperatively with your local building officials to help educate them about the technology and its characteristics.

What about insurance?

Your electric utility will require you to enter into an interconnection agreement, described more fully in the next section. Usually, these agreements set forth minimum insurance requirements that you must keep in force. If you are buying a PV system for your home, your standard homeowner's insurance policy

is usually adequate to meet the utility's requirements. However, if insurance coverage becomes an issue, contact one of the groups under Getting Help at the end of this series.

How do I get  an interconnection agreement?

Connecting your PV system to the utility grid will require you to enter into an interconnection agreement and a purchase and sale agreement. Federal law, and perhaps your state's public utility commission regulations, require utilities to supply you with an interconnection agreement. Some utilities have developed simplified, standardized interconnection agreements for small-scale PV systems.

The interconnection agreement specifies the terms and conditions under which your system will be connected to the utility grid. These will include your obligation to obtain permits and insurance, maintain the system in good working order, and operate it safely. The purchase and sale agreement specifies the metering arrangements, the payment for any excess generation, and any other related issues.

The language in these contracts should be simple, straightforward, and easy to understand. If you are unclear about your obligations under these agreements, you should contact the utility or your electrical for clarification.

National standards for utility interconnection of PV systems are quickly being adopted by many local utilities. The most important of these standards focuses on inverters. Traditionally, inverters simply converted the DC electricity generated by PV modules into the AC electricity used in our homes. More recently, inverters have evolved into remarkably sophisticated devices to manage and condition power. Many new inverters contain all the protective relays, disconnects, and other components necessary to meet the most stringent national standards. Two of these standards are particularly relevant:

  • Institute of Electrical and Electronic Engineers, P929: Recommended Practice for Utility Interface of Photovoltaic Systems. Institute of Electrical and Electronic Engineers, Inc., New York, NY (1998).
  • , UL Subject 1741: Standard for Static Inverters and Charge Controllers for Use in Photovoltaic Power Systems (First Edition). Underwriters Laboratories, Inc., Northbrook, IL (December 1997).

You don't need to fully understand these standards, but your PV provider and utility should. It is your obligation to ensure that your PV provider uses that complies with the relevant standards, so be sure to discuss this issue.

What about utility and inspection sign-off?

After your new PV system is installed, it must be inspected and “signed off” by the local permitting agency (usually a building or electrical inspector) and most likely by the electric utility with which you entered into an interconnection agreement. Inspectors may possibly require your PV provider to make corrections, but don't be alarmed—this is fairly common in the construction business. A copy of the building permit showing final inspection sign-off may be required to qualify for a solar rebate program.

What about warranties?

Warranties are key to ensuring that your PV system will be repaired if something should malfunction during the warranty period. PV systems eligible for some solar rebate programs must carry a full (not “limited”) twoyear warranty, in addition to any manufacturers' warranties on specific components. This warranty should cover all parts and labor, including the cost of removing any defective component, shipping it to the manufacturer, and reinstalling the component after it is repaired or replaced. The rebate program's two-year warranty requirement supercedes any other warranty limitations. In other words, even if the manufacturer's own warranty on a particular component is less than two years, the system vendor must still provide you with a two-year warranty. Similarly, even if the manufacturer's warranty is a limited warranty that does not include the cost of removing, shipping, and reinstalling defective components, the system vendor must cover these costs if the retailer also installed the system.

Be sure you know who is responsible for honoring the various warranties associated with your system—the installer, the dealer, or the manufacturer. The vendor should disclose the warranty responsibility of each party. Know the financial arrangements, such as contractor's bonds, that assure the warranty will be honored. Remember, a warranty does not guarantee that the company will remain in business. Get a clear understanding of whom you should contact if there is a problem. Under some solar rebate programs, vendors must provide documentation that specifies information on system and component warranty coverage and claims procedures. To avoid any later misunderstandings, be sure to read the warranty carefully and review the terms and conditions with your retailer.