It's not so easy after all

When it comes to solar photovoltaic (PV) systems, there's a common misconception that this growing technology — and the products that accompany it — are simple to install, modify, and maintain by untrained personnel. In reality, it's quite the opposite.

As this market continues to expand, there's actually a lack of qualified electricians and inspectors performing this type of work. As a result, many installed PV systems are not in compliance with the NEC and local regulations.

Let's take a look at some of the problem areas and why confusion still surrounds certain sections of the Code.

History lesson

Starting about 1973 in Braintree, Mass., the solar PV industry began in earnest in the United States with PV systems being installed on homes and businesses. The industry was not regulated until 1984 when Art. 690 was added to the NEC, which began addressing some of the different aspects that PV systems have from other electrical systems.

Since that time, the PV industry has rapidly evolved in technology and applications. Presently, the third generation of technology is commonly used. Although the NEC has changed quite a bit over this time period, a quick look at Art. 690 of the 1987 NEC reads very similar to the same section in the 2008 NEC. Why is this the case?

In the beginning, there was little guidance on how to use PV technology, and many inventive souls were quite creative in finding ways to tap this new energy source. Some early PV systems were as simple as using the DC voltage of the PV arrays to charge or supplement batteries that supplied DC power for lighting or homemade inverters. This gave way to more advanced inverters and eventually to systems that could connect to the electric utility grid. Each new development introduced another set of advantages as well as problems — not only from an installation perspective, but also from a safety standpoint.

Commercial use of small PV systems was sometimes difficult or expensive to install until the adoption of the 2008 NEC. One of the principal reasons for this resulted from language in the 2005 NEC that sometimes required the user to upgrade the main service — often doubling the service size — just to add a meager 2.5kW PV system to a subpanel. The rule change [690.64(B)] now allows the actual PV contribution to be considered at the main service and also includes the same bus loading provision that has been allowed on residential applications since 1987.

These are just a few examples that help demonstrate common PV installations. Because this niche will inevitably continue to change rapidly in the future, That's why it's more important than ever for electrical professionals to stay informed, stay safe, and stay trained on the latest changes in this ever-evolving industry.