15 Sep 2023
By Todd Fries
It’s hard to believe, but changes to the National Electrical Code (NEC), or NFPA 70, have already begun for NEC2026, the next code cycle. Every three years, the code panel meets to discuss public input regarding a host of different ideas and topics that impact safety. This includes labeling, which is always a very important topic; labels communicate hazards and critical information that can impact safety and performance.
This year is no different. Individuals and organizations like the Solar Energies Industry Association (SEIA) lead a variety of task groups, working on everything from bifacial installation requirements to grounding and bonding, which includes ideas on how to improve safety labeling.
One task group is dedicated to reviewing solar-related safety labeling. This group specifically evaluates proposals—it either rejects an idea or works to build consensus. Those proposed changes are then discussed within the larger group. If there is enough agreement on a specific change, SEIA will draft a formal public input and submit it to the NEC for review.
Those public inputs (PI’s) will eventually be reviewed by the appropriate NEC code panel during the first draft meetings in 2024. Following are some of the labeling changes being discussed for the next code cycle.
- Bifacial panel marking requirements. In the past, the only requirement for communicating voltage was to mark the maximum current. In article 690.8, the code indicates that the short circuit ratings (ISC) of the PV modules must be multiplied by 125 percent. The short circuit current is the highest current the solar panel cell can deliver without damage. But there are three ISC ratings for bifacial panels, so the question is: which one to use? The current code language does not specify. The code language in the NEC should harmonize with IEC/UL 61730-1 edition 3, which does specify the three types.
- Voltage marking requirements. There is a similar discussion happening in article 690.7(D) that states that, when marking PV DC circuits, a label indicating the maximum DC voltage of a PV system (calculated per 690.7(A)) must be provided at one of the following locations:
- DC PV disconnecting means.
- PV system electronic power conversion equipment.
- DC distribution equipment associated with the PV system.
The current label as specified in Article 690.7. The intent is to change the word “maximum” to “nominal.”
It has been suggested that the word “maximum” should be changed to “nominal” because this is not a calculated value, but it must be greater than the value calculated in 690.7(A). The task group feels that the industry wants a voltage label that indicates the minimum equipment rating for modules, inverters, meters, etc., that must be greater than or equal to the maximum open circuit voltage (VOC) of the system.
It is believed that using the maximum value can result in misapplication of the field marked label and provide more actional information for both inspectors and technicians. Some have suggested the maximum voltage value should still be part of the permit package, but should not be a “field-marking” requirement.
- Conductor colors. Finally, since we are talking about inconsistency in the code, there is some concern that the current code offers no consistency in the marking colors of conductors in articles 100, 200, and 690. An idea has been floated to develop a consistent description for marking grounded conductors. As an example, Articles 200.6(A) and 200.7 both specify that the insulation of grounded conductors have a continuous white or gray outer finish, or have three continuous white or gray stripes, while article 690.31(B)(2)(b) says that grounded conductors shall include an imprinted (+) or the word POSITIVE or POS durably marked on the insulation. Article 100 simply indicates that the definition for “functionally grounded” and “solidly grounded” conductors is not specific to PV systems.
The possible impact of this might be found in this example: On a multimode system with storage, PV circuit wiring is covered by article 690, but the remaining DC wiring (battery wiring, charge controller output circuit, etc.) falls under articles 706, 480 and 710, which do not make any specific distinction for functionality or solidly grounded conductor identification. That means the requirements covered under 200.6(A) and (B) and 200.7 would apply. If the code is applied as it stands, it is possible to have two circuits with the exact same grounding configuration and wires that are identified differently entering the same device.
Again, and just to be clear, the points discussed in this article are not approved changes for NEC2026. These are some of the many ideas being proposed and discussed across the country. Most will never make it past the first round of reviews, but it is good to know that so many people are thinking about how to improve code language—and to what degree.
The next edition of the NEC can be found at NFPA.org. The first draft report will be posted in July 2024.
Todd Fries is a product category manager of identification systems with HellermannTyton North America in Milwaukee, Wisconsin. He is on Code-Making Panel 4 of the NEC 2026, and is involved with the changes and additions discussed in this article.
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