Cable pulling on ships. Which rules apply and where it goes wrong.

When pulling cables on a ship, each cable is laid on prepared cable trays according to the cable list, fixed, routed through bulkheads and decks, and marked. The installation standard IEC 60092-352 and the rules of the classification society apply. Knowing the rules saves rework at acceptance.

01Which standard applies to cable pulling on ships?

IEC 60092-352 and the classification society rules named in the shipbuilding contract. The 2005 edition of IEC 60092-352 was withdrawn on 23 October 2025². It was replaced by Edition 4.0 of October 2025, with the new title ‘Selection, installation, and operating conditions of cables’. It covers voltages up to 18/30 (36) kV and adds new requirements for category cables up to 1000 MHz, for optical fibre cables and for transitions into hazardous areas³.

On top of this come the class rules, for example Lloyd's Register Part 6, Chapter 2, Section 11⁴, and the requirements of IACS, the umbrella association of the classification societies⁵. Class rules can have stricter or different values from the IEC. The shipbuilding contract states which edition and which class apply. That is the first question before any cable pulling.

02What bending radius applies to marine cables?

The cable manufacturer's value, but never less than the table value in the standard. For cables up to 1.8/3 kV, the 2005 edition of IEC 60092-352 gives these minimum radii, each as a multiple of the overall cable diameter D¹:

For cables from 3.6/6 kV, the values are 12D for single-core and 9D for three-core cables¹. Lloyd's Register gives the same values for high-voltage cables⁴. The cable manufacturer Prysmian recommends keeping to 1.5 times the table value during installation⁹. Watch the radius closely when pulling cables round corners and through penetrations.

03How do you pull cables without damaging them?

With limited pulling force, and not when it is too cold. Prysmian gives a maximum pulling force of 50 N per mm² of total conductor cross-section⁹. For a cable with three conductors of 95 mm² each, that is 285 mm² × 50 N/mm², or about 14 kN. According to the manufacturer, cables with a thermoplastic sheath should not be installed below −15 °C; pre-warmed, they can also be installed at lower temperatures⁹.

04How are cables fixed, and when are metal clips required?

On horizontal cable trays, the cables rest on supports no more than 400 mm apart and are fixed at least every 900 mm¹. Lloyd's Register gives the clip spacing by cable diameter⁴:

Where the cables rest on a cable tray, Lloyd's Register permits up to 900 mm⁴.

On metal clips, the rule sets differ. The purpose is the same in all of them: in a fire, cables must not fall, injure people or block escape routes.

So there is no single value. The class and the edition of the standard in the shipbuilding contract govern. If the shipyard has its own in-house standards, these apply as well. The safest way is to agree the spacing in writing before work starts.

05How do you segregate power, signal and high-voltage cables?

By cable category and with spacing, with high voltage always kept separate. IEC 60533 divides cables into four categories: power; signal and control; radio and video; high power and converters. Where cables of different categories run in parallel for more than 1 m, it recommends at least 10 cm spacing, and at least 20 cm between signal and converter cables, if the cables are no more than 5 cm above the ground plane. Otherwise it recommends heavily screened cables or metal conduits with a wall thickness of at least 1 mm⁸. These values are in the informative Annex B of IEC 60533. They are a recommendation, not a requirement. The specification decides whether they become binding.

There is no leeway for high voltage. High-voltage cables are not run in the same bunch, duct, pipe or box as low-voltage cables, nor on the same cable tray as cables up to 1 kV. In accommodation spaces they run in enclosed cable ducts^5,10.

Further rules from the standard and from Lloyd's Register^1,4:

• Cables with different permissible conductor temperatures do not belong in the same clip, penetration or duct.
• Redundant supplies to essential consumers run on separate routes.
• At hull expansion joints, the cable needs a loop with an inner radius of at least 12D.
• Single-core AC cables of one circuit are laid close together, no more than one cable diameter apart. No magnetic material may lie between them. Above 250 A, a clearance of at least 50 mm from steel is required, except when laid in trefoil.
• If more than six cables that are fully loaded at the same time are bunched without air circulation, their current-carrying capacity drops. Lloyd's Register applies a factor of 0.85 for this. Signal cables are exempt.

06What applies to cable penetrations through bulkheads and decks?

They must not weaken the watertightness or fire protection of the bulkhead. Penetrations through watertight bulkheads and decks must be watertight themselves. Cables passing through decks must be protected up to a sufficient height¹. Under Lloyd's Register rules, holes in non-watertight bulkheads are fitted with a bush, unless the steel is at least 6 mm thick and the edges are rounded⁴.

For watertight transits, the building yard keeps a register in accordance with IACS UR Z23. It lists marking, manufacturer's manuals, type approvals, installation drawings and the condition after final inspection. The surveyor checks installation, fixing, type approval and register. This applies to newbuildings with a shipbuilding contract dated 1 July 2021 or later⁶. At class renewal, all transits are examined again. Anyone who opens and repacks a transit must restore it to the manufacturer's instructions and the type approval⁷.

A type approval applies to a specific system and can be limited to specific installation situations. One DNV approval for a transit system, for example, only covers installation in sandwich panels¹². So a frame is not automatically watertight or A-60 just because the system has an approval.

A-60 means the division withstands fire for 60 minutes, and on the unexposed side the average temperature rise is no more than 140 K, with no point rising by more than 180 K¹³. A penetration in such a division must meet these values as well.

07How are cables marked on board?

To the system set out in the specification. IEC 60092-352:2005 provides for marking of the cable ends where this is required¹. High-voltage cables must be marked distinctly so that they are easy to identify^4,10. For each distribution board there is a circuit list showing the cable type¹¹. We did not find a general marking system in the rule sets cited. Whether cables are marked at both ends and at penetrations, and with which label material, therefore belongs in the specification.

08What mistakes happen during cable pulling?

These mistakes follow directly from the rules:

• Bending radius below the minimum during pulling, especially with high-voltage cables (12D, 9D) and foil-screened cables (8D).
• Only plastic ties on vertical runs, under trays or in escape routes.
• Pulling force exceeded, or cables with a thermoplastic sheath laid below −15 °C.
• Cables of different temperature classes in the same penetration.
• Transit not packed to its type approval, register and installation data missing.
• Signal and power cables without spacing run in parallel, screens not terminated.
• High voltage in the same bunch or on the same tray as low voltage.
• Redundant supplies on one tray, no loop at expansion joints.
• Ducts overfilled, more than 40 per cent.
• Single-core AC cables spread apart or with steel between them.

09What should be agreed before cable pulling starts?

1. Edition of the standard and class from the shipbuilding contract
2. Cable list with type, cross-section, length, start and end point of every cable
3. Status of cable trays and brackets: installed, coated, accepted
4. Spacing of metal clips and the shipyard's in-house standards
5. Who packs the transits and supplies the data for the register
6. Marking system and label material
7. Storage space for the cable drums, access routes, temporary site power and lighting
8. Which tests follow cable pulling and who records them

10How we do it at Electronautics

We take on cable trays and brackets, main-run and local cable pulling. Each cable is laid individually, fixed and marked. Our certified welders weld brackets for cable trays, penetrations and earthing studs on board to EN ISO 9606-1. At the end we test with test reports, and fibre optic cables with OTDR. Shipyards award cable pulling to us as a work package with our own crew and site manager, or bring electricians into their own team through temporary staffing.

Good cable pulling starts with the question of which edition of the standard and which class apply. After that, bending radius, fixing, segregation and properly made penetrations decide whether acceptance goes smoothly. Values on which the rule sets differ belong in the specification before work starts.