As modern vessel automation levels increase, cable density grows correspondingly. Power cables, control cables, communication lines, and optical fibers often share the same cable trays. Improper installation can lead to electromagnetic interference (EMI), causing signal loss and malfunction of automated equipment. More critically, in the event of a fire, the flame propagation along bunched cables poses a severe safety hazard.
Jiangsu Haizhongzhou Shipping Industry Co., Ltd. strictly adheres to the wiring principle of "Segregation by Tier, Separation by Bundle, and Isolation by Type."
Principle 1: Electromagnetic Compatibility (EMC) Layout
On main cable trunks, the tray system is designed with multiple tiers.
Top Tier (furthest from the steel deck): Carries low-voltage power circuits.
Middle Tier: Carries lighting and general control circuits.
Bottom Tier: Carries intrinsically safe circuits and instrumentation signal lines.
A minimum air gap of 50 mm is maintained between different tiers, and the bundling of different cable types within the same bunch is strictly prohibited. Coaxial cables for radar, communication, and navigation equipment are routed separately within enclosed galvanized steel conduits or dedicated shielded trunking to prevent harmonic interference from Variable Frequency Drives (VFDs).
Principle 2: Mandatory Segregation for Bunched Cable Fire-Retardancy
While individual marine cable sheaths are flame-retardant, the heat accumulation effect within a cable bunch can accelerate combustion. During installation, we strictly enforce maximum bunch cross-sectional area limitations. For cable penetrations passing through "A-Class" fire-rated divisions, we apply intumescent fire-rated sealant and modular fire-stop blocks. This modular blocking system ensures maintainability for future cable replacement while also providing expansive foaming action during a fire, effectively sealing off the passage of flames and toxic smoke.
Principle 3: Drip Loop Technique for Equipment Entries
For cable entry conduits serving exposed deck equipment (such as windlasses and mooring winches), we mandate the fabrication of a U-shaped drip loop, with a drain hole provided at the lowest point of the bend. This serves as the final line of defense against rainwater ingress traveling along the cable into the main switchboard room. Though a minor detail in terms of physical work, this technique is critical in mitigating the risk of a complete vessel blackout.