Outdoor monitoring instruments, industrial control micro solenoid valves, and small actuators are constantly exposed to temperature differences and humid vibration environments. Ordinary thin wires are prone to insulation aging, wire breakage, and leakage faults. The fine line for special working conditions adopts improved insulation coating, which is moisture-proof, vibration resistant, chemical resistant, and has long-term stable electrical performance. The wire structure balances slim volume and mechanical strength, meeting the long-term uninterrupted operation requirements of various small industrial electronic control components and expanding the application boundaries of fine wire in the field of industrial automation.