The wires for the temperature controllers of air conditioners and refrigerators form a low-voltage, low-current system with extremely high requirements for insulation and reliability. It is not merely a simple power connection; it is a channel for transmitting control signals.
I. Core Functions and Features
The wires for the temperature controllers primarily serve two functions in refrigeration equipment:
1. Signal Collection and Transmission: Connecting temperature sensors (usually thermistors) to the main control board. This wire transmits weak resistance signals that change with temperature, which are highly susceptible to interference.
2. Control Command Transmission: Connecting the temperature controller (or the main control board) to the compressor, fan, heater (for defrosting in refrigerators), four-way valve (for reversing in air conditioners), etc., as control components. These wires transmit on-off commands or speed control signals.
Features: The voltage and current are not large: the signal wires are in the milliampere range, and control wires are usually relay outputs, with currents generally below 10A. Special environment: They may come into contact with low-temperature condensate water, grease, slight vibration and compression. The reliability requirement is extremely high: If the cable ages or has poor contact, it can cause faults such as the equipment not cooling, not stopping, or defrosting failure.
II. Wire Types and Structures
The wires inside air conditioners and refrigerators are mainly divided into the following types:
1. Sensor Leads (Signal Wire)
This is the most “precious” wire, used to connect thermistors.
Conductor: Usually multi-strand ultra-fine copper wire, very flexible, suitable for wiring in narrow spaces.
Insulation Layer: Commonly PVC (polyvinyl chloride) or XLPE (cross-linked polyethylene). XLPE has better heat resistance and anti-aging properties.
Key Structure: It must be a twisted pair!
Two signal wires (usually red and white/black) are tightly twisted together. This can effectively resist external electromagnetic interference, ensure the accuracy of the temperature signal, and prevent the main control board from receiving incorrect signals due to misjudgment.
Shielding Layer: In high-end equipment or environments with particularly strong interference, the sensor wire will add an additional layer of aluminum foil Mylar shielding, providing better shielding effect.
Appearance: Usually flat twisted wires in white or black, or very thin circular wires.
2. Load Control Wires (Power Wire)
Used to connect compressors, fan motors, etc., for high-power components.
Conductor: Multi-strand copper wire, but thicker than the sensor wire, with the cross-sectional area determined by the load current (for example, compressor wire may use `1.5mm²` or `2.0mm²`, fan wire may use `0.75mm²`).
Insulation Layer and Sheath: Use flame-retardant PVC or rubber insulation. It requires good heat resistance (close to the high-temperature compressor), flame retardancy (first and foremost safety), and certain flexibility.
Color Marking: Strictly follow electrical color standards for easy installation and maintenance: Brown/Black/Red: Hot wire (L), Blue: Neutral wire (N), Yellow-Green: Ground wire (PE)
3. Indoor and Outdoor Unit Connection Wires (Interconnecting Cable)
4. For split-type air conditioners, connecting the indoor unit and the outdoor unit.
5. Structure: This is a multi-core cable, usually combining the above wires within a single sheath.
Common Configurations:
3-core cable: 1 hot wire (L) + 1 neutral wire (N) + 1 ground wire (PE). Used for early or simple models.
4-core cable: 1 hot wire (L) + 1 neutral wire (N) + 1 ground wire (PE) + 1 signal wire (S). The signal wire is used for communication between indoor and outdoor units.
5-core cable: In addition to the 4-core configuration, an additional wire or for more complex control functions is added.
Requirements: This cable needs excellent weather resistance because some wires will be exposed outdoors, needing to resist ultraviolet rays, temperature changes, and rain.
Post time: Sep-12-2025