ASK THE EXPERTS: PV System Labels

The 2008 National Electrical Code (NEC) requires signage on various parts of PV systems. What are the specific requirements for each sign? Where can I buy these signs? I want to have them in place before the rough-in inspection.

Roger Carver • Nucla, Colorado

Section 690 of the NEC specifies requirements for labeling PV systems. There are multiple labeling requirements, and they are spread out among several subsections. The labels are required to be a durable, unalterable material permanently attached to the device. The most common type of labeling is engraved or etched plastic, which can be riveted or adhered to the device.

The first NEC requirement is that the PV power source information be posted at the DC disconnect, which can also be part of the inverter. Section 690.53 lists the posting requirements: rated maximum powerpoint current, rated maximum power-point voltage, maximum system voltage, and short-circuit current. According to 690.14(C)(2), if there is more than one PV DC disconnect, they should also be labeled.

The NEC also requires other labels for:

• The DC disconnect, noting that the line and load sides may be energized in the open position (NEC 690.17).
• The AC disconnect—stating the rated AC output current and nominal operating AC voltage (as stipulated by NEC Sections 690.14[C][2] and 690.54).
• At the location of the ground-fault protection, normally at the inverter, warning of a shock hazard (NEC690.5[C]).
• Where the solar-electric system interconnects to the utility (NEC690.54).

Photovoltaic systems that include batteries have a few other labeling requirements. In addition to NECrequirements, it is a good idea to also label other DC enclosures, the utility disconnect, and combiner boxes with fuses, while also providing information at the utility meter that there is a PV system connected.

Try your local sign-making or trophy shop for pricing. Tyco (www.tycoelectronics.com) makes some labels that may meet your needs. And be sure to pay attention to NECSection 690 for any labeling changes that might come up.

Matthew Dickey, Argand Energy Solutions • Charlotte, North Carolina