National Electrical Code Tips: Article 690 -- Solar Photovoltaic Systems, Part 1
Only about 15% to 20% of the work of installing a Solar Photovoltaic (PV)
System is electrical. But that electrical portion can easily result in disaster
if not done correctly. Thus, Article 690 provides requirements for that portion.
- Article 690 does not cover small solar-powered devices, such as patio lamps,
flashlights, automobile ventilators and other assorted gadgets.
- Article 690 does cover solar power systems, including those that are
interactive with other power systems [690.1].
- The NEC provides a simple diagram that clearly illustrates PV system
components [Figure 690.1(A)].
- The NEC provides a set of simples diagram that clearly illustrate solar
photovoltaic (PV) system components in three common system configurations
[Figure 690.1(B)]. These are stand-alone, hybrid, and interactive.
- A hybrid system is one comprised of several power sources [690.2 and Figure
690.1(B)]. For example if you combine a wind turbine generator with a solar
system, you have a hybrid system.
- A system is "interactive" if it connects to the power network [690.2 and
- A charge controller is different from a diversion charge controller. The
former controls the dc voltage (or dc current) use to charge a battery. The
latter regulates the battery charging process by diverting power from energy
storage to the load or to the utility [690.2].
- You still must apply Chapters 1 through 4, but where the requirements differ
from Article 690 then you go with the Article 690 requirements [690.3].
- If the PV system operates in parallel with a primary source of electricity
(e.g., the electric utility), then the requirements in 705.14, 705.15, 705.32,
and 705.143 apply [690.3].
- If you install a PV system in a hazardous location (as defined by OSHA and
as defined in Article 500), you must apply the relevant Articles 500 through
516. A location is hazardous if the presence of combustibles is high enough to
risk a fire. If the combustibles are gases, dust, or fibers, the location is
Class I, Class II, or Class III respectively.