In a DC system, what color finish can be used to identify the negative ungrounded conductor?

In a DC system, the standard practice for identifying conductors involves using specific color codes to facilitate proper connection and safety. The color black is widely accepted as the designation for the negative ungrounded conductor. This convention is established to maintain consistency across electrical systems, ensuring that technicians and electricians can easily identify and work with the correct wiring without confusion.

Using black for the negative conductor helps avoid potential hazards that could arise from misidentification of wires, especially in a system that may also contain other colored conductors. Other colors like red are typically used to signify positive ungrounded conductors, which reinforces the importance of adhering to these established color codes. Green is designated for grounding conductors, and blue is often used in AC systems for different phases or conductors but does not apply to DC negative conductors. Thus, black serves as the clear and established choice for identifying the negative ungrounded conductor in a DC wiring system.