By TEBAOFLEX Jyen. Originally published on September 10, 2026.
A dynamic subsea cable changes curvature and tension during service. A towed instrumentation cable may also experience winch handling, rotation and vehicle loads. These duties need a defined mechanical qualification program; a submarine power-cable standard or a large cycle count is not, by itself, evidence of suitability.
Use each reference within its scope
IEC 63026 addresses fixed submarine power cables with extruded insulation and rated voltages from 6 kV to 60 kV. It is not a general dynamic-cable qualification or a blanket standard for 66 kV systems. CIGRE Technical Brochure 722 discusses additional submarine-cable tests. Technical Brochure 862 specifically addresses mechanical testing for dynamic applications. Select the relevant product, accessory and project requirements together.
Translate the service model into a test plan
- Define water depth, suspended configuration, installation loads, operating tensions, bending locations, temperature and expected service duration.
- Develop representative load combinations and a fatigue spectrum from the project analysis, including unusual operating conditions and handling events.
- Document specimen length, end restraints, bend geometry, axial force, cycle definition, frequency and environmental conditioning.
- Explain how accelerated testing represents service damage and its limitations. A fixed million-cycle total cannot automatically represent a stated number of years.
Test the interfaces as well as the cable
Hang-offs, clamps, bend-control devices, splices and terminations can change local stresses. Qualification specimens should represent the interfaces that govern the design. A tensile proof test and a destructive termination pull-out test answer different questions. Their loads, acceptance criteria and witnessing requirements must come from the approved design, not a universal percentage of cable breaking strength.
Optical attenuation, electrical insulation, conductor continuity and component movement may be monitored before, during or after loading as appropriate. Stable attenuation is not direct proof of zero fibre strain. Define the instrument resolution and permitted changes, including residual changes after recovery.
Pressure tests need their own engineering basis
Specify whether pressure acts externally on the assembled cable, internally in a hydraulic component or longitudinally through a damaged section. These are different tests. Fluid, temperature, hold time, pressure cycling and decompression rate matter. Any pressure factor must be justified by the governing requirement and equipment design; it is not an automatic multiplier for every subsea cable.
Qualification versus production acceptance
Full-scale fatigue qualification usually examines a representative design. Routine production checks establish conformity of supplied lengths. The inspection and test plan should state which records are per drum, which are sample tests and which refer to a previously qualified construction. Changes in materials, dimensions or terminations need a documented assessment of qualification coverage.
Pressure and destructive mechanical tests require a qualified facility with suitable containment and an approved safety procedure. Procurement documents should request traceable results and deviations, not prescribe an improvised socketing or deck-test procedure.
Sources and scope
IEC 63026: fixed submarine power cables
CIGRE TB 722: additional submarine cable tests
CIGRE TB 862: mechanical testing for dynamic applications
These references explain the relevant methods or manufacturer guidance. They do not certify a TEBAOFLEX product or establish results for a supplied batch.
Discuss your specification
For a project-specific cable specification, send the duty, installation drawing and required acceptance criteria to TEBAOFLEX. WhatsApp: +86 185 9591 3361. Request documented product ratings and test evidence before approval.