Which method is acceptable for identifying polarity in PV system DC circuit conductors at all termination points?

Color coding is the accepted method for identifying polarity in photovoltaic (PV) system direct current (DC) circuit conductors at all termination points. This approach provides a clear, standardized visual cue that enables anyone working with the system to quickly and easily ascertain the positive and negative conductors. The use of specific colors for different polarities—such as red for positive and black for negative—helps ensure a uniform understanding and reduces the risk of connection errors, which could lead to safety hazards or system malfunctions.

While other methods, like labels or numbering systems, may help in identification, they do not provide the innate visibility and immediate recognition that color coding does. Labels can deteriorate or become unclear over time, and a numbering system may require additional interpretation to determine polarity. A permanent marker, on the other hand, is less reliable because it might fade or smudge, making it difficult for someone to accurately identify the conductors later on. Color coding implemented as per NEC guidelines thus remains the best practice for clearly indicating polarity at all termination points in a PV system.