It is absolutely essential for all homeowners to understand how solar photovoltaic systems work. The HSEA found, through our own research, that many other "How Solar Works" diagrams ignore a lot essential details, including proper racking and flashing requirements. In this diagram, we point out all of the critical components for a successful solar photovoltaic system for your home. HSEA member contractors are all well versed and understand Hawaii's local installation codes better than any other contractor. Below is the HSEA's own diagram that shows all critical components to a successful solar photovoltaic system:
In this diagram, we detail the required equipment for a centralized inverter system.
ON THE ROOF:
On the rooftop, you'll notice we have broken down a solar installation into three parts to show the critical components; Solar Panels, Racking and Flashings. It is very important to ensure that your contractor is aware of these requirements. It is ALWAYS best to choose a contractor that offers a high quality flashing method. A savings of $5000 by choosing a contractor that does not use a flashing may end up in over $40,000 in leak and mold damage repairs!
Secondly, it is important to know what type of racking system your installer is using. It is important to know that the installer has chosen a high quality racking system that is rated for the wind rating in Hawaii, which is 105 miles per hour (mph). However, installers should NOT be aiming to satisfy only 105 mph. Installers should always have a safety factor and therefore install at a rating that exceeds 105 mph. Most importantly, a racking system is only as strong as the amount of penetrations into your rooftop. Many contractors may suggest that their racking system can be installed at long distances between penetrations, but they may have not performed the calculations to justify such recommendations.
Lastly, the solar panel you choose should be mounted properly. A properly installed system should not extend beyond the top of the roof. A properly installed system will usually remain at least 1.5 feet from all edges of the rooftop.
ON THE GROUND:
1.) Inverter: The centralized inverter controls all of the solar panels located on the rooftop. The inverter then outputs usable household AC power to a utility required AC disconnect (required via HECO).
2.) AC Disconnect: The Alternating current (AC) disconnect is a requirement from your utility company (HECO, HELCO, MECO, KUIC) and not to be confused with Air Conditioning (A/C). Not all states require an AC disconnect but considering the way it mitigates risk by allowing utility personal to ensure power shutdown during grid maintenance, it is worth the addition.
3.) Subpanel: The subpanel may not always be required on-site, but many times a contractor will be required to re-feed existing household loads in order to complete the final interconnection with the utility meter.
4.) Utility Meter: The utility meter is where your final interconnection is made. There are many different types of utility meters: Analog, Analog with Antenna, Digital, and Digital NEM. The only two types that are compatible with PV systems are Analog and Digital NEM. All other meter types should not have an activated PV system until the utility replaces the meter with a Digital NEM meter.
All art provided and donated in part by Ryan Johnson, ArtistRendering.com