Marine cable laying is the key link of ship electrical installation. The quality of cable laying technology directly affects the normal and safe operation of ship power distribution system and the effective and reliable operation of electrical equipment. It can be said that the service life of a ship power system is closely related to the laying technology of cables. Adopting scientific and reasonable construction technology is the basis to ensure the cable laying standardization, but also reduces the workload of ship construction inspection.

Overview of cable laying process

Cables should be laid in layers and bundles, as flat as possible. A removable movable cover should be installed when the main circuit cable is dark mounted.

The bending radius of cable bending is shown in the following table:

Cable wiring should avoid the influence of moisture or oil and water condensation as far as possible.

Cables should be kept away from heat sources such as boilers, heat pipes, resistors and so on. The distance between the heat insulation layer of the mobile flat cable and the steam pipe or exhaust pipe should not be less than 25mm.

When the cable passes through the bulkhead, the distance between the cable barrel (or frame) and the steam pipe flange shall not be less than 450 mm when the steam pipe diameter is greater than 75 mm, and not less than 300 mm when the steam pipe diameter is equal to or less than 75 mm.

Main cables should not be laid on the top of the mechanical equipment with crane cylinder, such as air compressor and diesel engine, otherwise, measures should be taken to prevent mechanical damage.

Cables with different sheaths or outer sheaths should not be bundled together if other cable sheaths or outer sheaths may be damaged during laying.

Cables of important equipment or emergency power, emergency lighting and communication equipment used in emergency situations should be kept as far away as possible from kitchens, laundries, machine premises, engine room shelters and other places with greater fire hazards, except for cables supplied by equipment in these places.

Trunk cables are not allowed to be laid in various insulating materials. Local (terminal equipment) cables installed in non combustible insulating materials should reduce load accordingly.

If the power cable and the computer signal cable are laid on the same bracket, they should be strapped and tied separately.

Intrinsically safe circuit cables and non essential safety circuit cables can not be laid on the same bracket in principle. When unavoidable, the spacing should not be less than 50 mm, but it should be noted that it must not be allowed to pass through the same cable tube (frame).

The cables to main generators should be far away from individual installations and divided into two main cables.

All cables to the two steering gear should be laid separately on the left and right sides.

Cables unrelated to radio equipment should avoid passing through the room. If unavoidable, mobile special soft cables should be laid in the cable tube.

Generally, cables should not pass through oil and water tanks.

Radio stations should be equipped with dedicated batteries, batteries to the fuse box cables should be single-core or single polar cable, laying separately, usually on the same deck.

Except for a single cable, the total cross-sectional area of the cable passing through the cable tube, frame and tube shall not exceed 40% of the cross-sectional area of the inner wall of the tube, frame and tube. The cable penetration coefficient of the cable box and frame needed to fill the sealing filler should not exceed 0.3.

Matters needing attention in cable laying

Fastening of cables

The distance between cable supports is not more than 350mm in principle. When laying horizontally, tie the tape tightly to each of the supporting boards.

At the time of laying, tie up the tape at each pallet. Cable through parts can not be used as supporting parts. In principle, each bundle of power cables shall not exceed two layers or not exceed 50 mm in thickness, and each bundle of cables shall be 200 mm in width. When multi-layer brackets are used, the spacing between brackets shall be at least 120 mm, and the distance between cable barrels (frames) and brackets shall be at least 120 mm. The cables in the cabin can be placed directly in the groove of the decorative board if the cables are laid in a dark way. If the cables need to be transversely connected to the electrical equipment, the cables in the cabin can be placed in the groove of the decorative board. The cables in insulation shall not exceed 300mm.

Protection for cable laying

The cables on the open deck should be laid through pipes and galvanized steel pipes should be used. The horizontal installed cables have at least one leak hole with a diameter of 6. The cables on the deck deck should be protected in places where it is not easy to pipe laying (including waveguide). The cables in the deck cable tube telescopic box shall have sufficient margin (at least 1% of the cable length) and shall be placed on the flexible guide plate to compensate for the expansion deformation of the hull, and there shall be no relative movement between the cable and the guide plate.