luna@lunaele.com
The function of the wire harness is usually not “all solved with one wire”, but is designed in segments according to the electrical purpose and signal characteristics. Generally, we can understand “which sections are power supply/signal/data/shielding/high voltage and low voltage respectively” and their corresponding relationship in engineering.
1) Power supply section (Power)
The power supply section is used to continuously provide energy to the load, typically the main power supply, distribution power supply, power supply line that drives the motor/heater/pump, etc. It usually has a higher current capability and focuses on wire diameter (cross-sectional area), voltage drop, temperature rise, electrical safety, temperature and oil resistance, etc. The power supply wiring harness is often arranged near the power device, and the wiring is short or the wiring method is more “heat dissipation and reliable fixation”.
2) Signal segment (Signal/Low-level control)
The signal segment refers to the line used to transmit switching or low-level control information (such as sensor output, switching input, control terminal status feedback). It generally has a small current and focuses on voltage amplitude, noise tolerance, anti-interference, and terminal and connector reliability. The wire gauge can be thinner, but the insulation and shielding (if any) requirements are more stringent.
3) Data segment (Data/Communication)
Data segments are wires used for communication protocol transmission, such as CAN, LIN, Ethernet/High Speed Serial Differential, etc. Different from general signals, the data segment emphasizes transmission integrity: characteristic impedance, line pair matching, length deviation, crosstalk control, transmission delay, shielding continuity, etc. (especially high-speed data). Therefore, the structure of the data harness is more “engineered” and may require twisted pairs/split screens/controlled bending radius.
4) Shielding
The shielding section is not an independent “power supply or signal”, but a structural design to resist electromagnetic interference for a certain type of line (usually signal/data). The shielding layer (copper mesh/aluminum foil/braid, etc.) “guides away” external interference through grounding, making the effective signal in the line more stable. The key to the shielding section is: shielding material and coverage, shielding layer continuity, ground connection point method (single-ended/multi-ended) and grounding strategy.
5) High voltage / low voltage
The high-voltage section and the low-voltage section depend on the electrical classification of the system.
The high-voltage section generally refers to the higher voltage level part of the power supply system (such as the high-voltage area of the power battery of some new energy platforms and the high-voltage connection from the inverter to the motor). It focuses on creepage distance/clearance, withstand voltage, insulation material and thickness, shielding and EMC, protection against electric shock, etc.
The low-voltage section includes ordinary control power supply, sensor power supply, low-power actuator power supply, and communication and signal-related wiring harnesses. Its focus is more on stability, noise and reliable connections.
To summarize in one sentence:
The wire harness can be divided into “power supply section (for energy)/signal section (for control information)/data section (for communication content)” according to function; the “shielding section” is a structure added to improve signal/data anti-interference; the “high voltage section/low voltage section” is the safety and process division of the entire wire harness (which may include power supply and some signals) according to voltage level.