The blank part of the line usually refers to the insulation layer in the wire. Electric wires consist of conductors, insulation layers, and shielding layers (if any). The conductor is the core part of a wire, responsible for conducting electricity; The insulation layer is wrapped around the conductor to provide isolation and protection, preventing current leakage or short circuit. The insulation layer is usually white, so in some cases, white wires may represent the insulation layer.
In addition, the blank areas in the wires may also be used to identify different circuit functions. For example, in some cables, white wires may be used to identify specific circuits or signal lines. This identification method helps distinguish different lines during installation and maintenance.