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In the in-depth design of modern urban lighting systems, 220V low-voltage power supply lines remain the "main arteries" for the vast majority of traditional street lamps and some smart street lamps. Unlike high-voltage transmission which requires huge towers and insulator strings, nor does it rely on complex rectifier and inverter modules like DC microgrids, it remains the mainstream in scenarios with relatively dispersed loads such as residential areas, auxiliary roads, and landscape walkways due to its simplicity, economy, and ease of maintenance. Starting from the outgoing line of the distribution box, copper or aluminum core polyvinyl chloride insulated cables are laid along the pre-buried PVC corrugated pipes or galvanized steel pipes in a meandering manner. A waterproof wiring well is set every 30 to 50 meters, and the well adopts a crimping terminal + potting sealing process, which not only isolates underground moisture but also reserves a window that can be repeatedly opened for later maintenance.
However, when urban managers put forward the demand for intelligent upgrades such as "single-lamp control, dimming energy conservation, and self-diagnosis of faults", the pure 220V AC power supply seemed "powerless despite its best intentions". Although each LED lamp retains AC/DC constant current drive inside, to enable the driver chip to understand instructions such as "the brightness drops to 70% after 8 p.m. tonight" and "preheat to 90% before 5 a.m. tomorrow", an additional "neural network" - signal lines - must be laid.

The entry point of Zhongzhen's cable solution lies precisely here: to make the reliability of signal lines comparable to that of 220V power lines, rather than becoming the shortest plank in the system's barrel effect. Its design logic can be broken down into four dimensions:

1. Conductors and stranding: Whether it is RS-485, CAN or PLC carrier, the conductors of the signal loop all adopt a higher grade of oxygen-free copper than conventional communication cables, with a single wire diameter of 0.4 to 0.51 millimeters, and are stranded in 7 or 19 strands in a standard manner.
2. Insulation and shielding: The insulation layer is made of irradiated cross-linked PE, with a volume resistivity of ≥1×10^14 Ω·cm and a dielectric constant stable at around 2.3, ensuring that the signal transmission attenuation is less than 3 dB/km. The shielding layer adopts a double-layer structure - the inner side is 100% covered aluminum-plastic composite tape, and the outer side is tin-plated copper wire woven mesh, with a weaving density of ≥85%.

3. Sheath and armor: The sheath material is UV-resistant black polyvinyl chloride, with UV-531 and HALS light stabilizers added. After 1000 hours of xenon lamp aging test, the tensile strength retention rate is ≥90%.
4. Waterproofing and connectors: The entire signal cable undergoes a 3bar air pressure immersion test before leaving the factory to ensure that no air bubbles escape per meter of length at a water depth of 10 meters for 24 hours.
After the implementation of this dual-line parallel solution of "220V power + central signal", urban street lamps will have a complete closed loop of "perception - thinking - execution" : The photosensitive probe collects the ambient illuminance in real time, and the motion sensor detects the density of people and vehicles. The 4G/5G module transmits the data back to the cloud platform. The AI algorithm issues a dimming command within 15 seconds, which is directly transmitted to the lamp driver via the Zhongzhen signal line. Finally, a stable energy is provided by a 220V low-voltage line.