IEC 60092-350:2020 pdf download – Electrical installations in ships – Part 350: General construction and test methods of power, control and instrumentation cables for shipboard and offshore applications.
Core identification
All cores shall be clearly identified.
The cores of multi-core cables or cores within pair,triple or quad unit(s)shall be identified by colour or numbering as given in the applicable product standard.
The colour or numbering shall be clearly identifiable and durable.
Spacing and dimensions of any numbering shall be as given in the applicable product standard.
Conformity shall be checked by visual examination,and the durability of the print where applicable shall be in accordance with the test as given in 8.20.

IEC 60092-350 provides the general constructional requirements and test methods for use in the manufacture of electric power,control and instrumentation cables with copper conductors intended for fixed electrical systems at voltages up to and including 18/30(36)kV on board ships and offshore(mobile and fixed)units.
The reference to fixed systems includes those that are subjected to vibration (due to the movement of the ship or installation)or movement (due to motion of the ship or installation)and not to those that are intended for frequent flexing.Cables suitable for frequent or continual flexing use are detailed in other IEC standards,for example IEC 60227 (all parts)and IEC 60245 (all parts),and their uses are restricted to those situations which do not directly involve exposure to a marine environment,for example,portable tools and domestic appliances.