AE 868
Commercial Solar Electric Systems

Labeling and Marking


We saw in the previous example that the ISEP adopted IFC 605 for electrical equipment, warning and hazards. In addition, the National Fire Protection Association NFPA 70 (NEC 690) and International Fire Code (IFC 605) both require that marking is needed to provide emergency responders with appropriate warning and guidance with respect to isolating the solar PV system. This helps in identifying energized electrical lines that connect the solar modules to the inverter to prevent cutting these wires when venting for smoke removal.

Materials used for marking should be able to withstand extreme weather conditions. Different materials can be used for warning signs. Vinyl signs need to meet UL requirements, while plastic and metal engraved signs do not need to meet any UL standards.

In rare cases, fire can be caused by solar modules. An example of this occurred in a residential application in New Rochelle, NY. Complying to marking and labeling code requirements can help firefighters find the energized circuits in the property and disconnect the power to safely work on the property.

Labeling is required at certain locations in the electrical PV system, such as:

  1. PV modules labels: usually provided by manufacturers and has main electrical parameters such as current, voltage, and power.
  2. Disconnect labels: Either AC or DC sides, all disconnects need to be labels and visible. Labels must include maximum current and voltage. For PV systems, labels need to list the operating voltage as well. In addition, a warning sign needs to be placed on disconnect where terminals may remain energized in the open position.
  3. Point of connection labels: This is specific to interactive systems. A label needs to be located at the point of interconnection and must identify the interconnection utility service.
  4. Other energy source labels: For any other energy source such as batteries, labels must indicate the maximum operating voltage and polarity of a DC system.
  5. Grounding labels: Whether the system is grounded or ungrounded, labels must identify the ground-fault current and a warning signage stating the grounded system may be ungrounded and energized.


For more information about labeling and marking, refer to Chapter 13 in the required reading of the textbook and National Electrical Code section on the National Fire Protection Agency (NFPA) website.