English1. Identify electrical parameters
Voltage level
Confirm the working voltage of the wiring harness (such as 12V, 24V, 220V, etc.), and select wires with matching insulation levels (such as 250V, 600V, etc.).
High-voltage applications require high-voltage resistant wires (such as silicone wires, Teflon wires).
Current carrying capacity
Select the wire diameter (cross-sectional area) according to the rated current of the relay/transformer. For example:
Below 1A: 0.3~0.5mm²
5A: 0.75~1mm²
10A: 1.5~2.5mm²
For higher currents, calculate the temperature rise and derating (refer to IEC 60287 standard).
Signal type
Control signal lines (low current) can use thin wires (such as 0.2mm²); power lines need to be selected according to the load current.
2. Wire material selection
Conductor material
Copper wire: conventional choice (good conductivity, moderate cost).
Tinned copper wire: anti-oxidation, suitable for humid environments.
Aluminum wire: lightweight, low cost, but requires a larger cross-sectional area.
Insulation layer material
PVC wire: general purpose, temperature resistant -40℃~105℃, low cost.
Silicone wire: high temperature resistant (-60℃~200℃), good flexibility, suitable for high temperature environment.
Teflon wire: corrosion resistant, high temperature resistant (260℃), used in harsh environments.
3. Environmental adaptability
Temperature range
For high temperature environments (such as engine compartments), choose silicone wire or XLPE cross-linked polyethylene wire.
For low temperature environments (such as outdoor in the north), choose cold-resistant PVC or rubber wire.
Protection level
For humid/oily environments: choose waterproof wire (such as IP67 grade) or sheathed wire harness.
Abrasion resistance requirements: add braided shielding layer or armor (such as galvanized steel wire).
4. Mechanical and connection requirements
Wire harness length and flexibility
For frequently moving scenes (such as robotic arms), choose highly flexible cables (such as multi-strand thin copper wire).
Single-core hard wire can be used for fixed installation.
Terminal and connector matching
Confirm whether the terminal type (such as plug-in type, ring terminal) and aperture match the relay/transformer interface.
Crimp reliability: The wire diameter and terminal crimping range must be consistent (such as 1.5mm² wire with 1.5-2.5mm² terminal).
5. Safety and certification
Industry standards
Automotive electronics: Comply with ISO 6722 or LV 112-3 standards.
Industrial equipment: Comply with UL 758 (AWM), CE or RoHS directives.
Household appliances: CCC certification (China) or VDE certification (EU) is required.
Flame retardant requirements
Flame retardant ratings (such as UL94 V-0) are particularly important for high-density or enclosed spaces.
6. Practical application case reference
Automotive relay wiring harness:
Select 0.5~2.5mm² tinned copper wire, silicone insulation, oil and high temperature resistance.
Industrial control transformer wiring:
1.5~4mm² PVC wire, with shielding layer for anti-interference.
Low-voltage line of household appliances:
0.2~0.75mm² oxygen-free copper wire, flame-retardant PVC outer sheath.
Summary steps
Determine the current/voltage → 2. Select the wire diameter and material → 3. Match the environmental requirements → 4. Verify the terminal compatibility → 5. Check the certification standards.
If you need a more precise selection, you can provide specific application scenarios (such as automobiles, industry, and household appliances) for further analysis!
