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flexible medium voltage

26 Min Read
The continuous ampacity of (N)TSCGEWÖU 3x120+3x70/3 12/20kV flexible reeling cable is 360 amperes when operating as a single conductor run in free air at the reference condition of 30°C ambient temperature and 90°C conductor operating temperature according to VDE 0250-813 and DIN VDE 0298-4 standards. For tunnel boring machine cutterhead power supply applications where the cable is installed in the constrained environment of a TBM backup gantry system—bundled alongside control cables, communication lines, and other power feeders—and subjected to frequent mechanical stress from dragging and reeling operations, the practical safe ampacity derates to approximately 260–285 amperes depending on specific installation geometry, tunnel temperature profile, and frequency of mechanical cycling. These two ampacity values represent the boundary between theoretical maximum current capacity and the practical operating limit for reliable power delivery to a 2–3 megawatt main cutterhead drive motor in a hard-rock tunneling or soft-ground excavation system. Understanding where these values come from and how they apply to specific TBM configurations is essential for preventing unexpected power loss to the cutterhead, which could force a full machine shutdown and result in schedule delays of weeks or months in confined underground construction.
Technical Department
on28/02/2026

TBM Cutterhead Power Supply: How to correctly size (N)TSCGEWÖU 3×120+3×70/3 12/20kV flexible reeling cable for tunnel boring machine main drive systems 

The continuous ampacity of (N)TSCGEWÖU 3×120+3×70/3 12/20kV flexible reeling cable is 360 amperes when operating as a single conductor run in free air at the reference condition of 30°C ambient temperature and 90°C conductor operating temperature according to VDE 0250-813 and DIN VDE 0298-4 standards. For tunnel boring machine cutterhead power supply applications where the cable is installed in the constrained environment of a TBM backup gantry system—bundled alongside control cables, communication lines, and other power feeders—and subjected to frequent mechanical stress from dragging and reeling operations, the practical safe ampacity derates to approximately 260–285 amperes depending on specific installation geometry, tunnel temperature profile, and frequency of mechanical cycling. These two ampacity values represent the boundary between theoretical maximum current capacity and the practical operating limit for reliable power delivery to a 2–3 megawatt main cutterhead drive motor in a hard-rock tunneling or soft-ground excavation system. Understanding where these values come from and how they apply to specific TBM configurations is essential for preventing unexpected power loss to the cutterhead, which could force a full machine shutdown and result in schedule delays of weeks or months in confined underground construction.
34 Min Read
The act of splicing a medium-voltage cable in the field—joining two cable ends after they have already been installed in a drilling derrick or FPSO electrical room—occupies a unique and critical position in offshore electrical engineering. Unlike cable terminations (where the cable end is terminated to a switchgear cabinet or transformer winding terminal), field splices create a permanently joined section within the cable run itself. This joint must perform as if it were part of the original manufactured cable, maintaining perfect electrical, mechanical, and dielectric integrity in one of the world's most hostile environments: the vibration-laden, salt-spray-corroded, perpetually humid confines of an offshore platform. When a splice fails, it often fails catastrophically, potentially causing equipment damage, electrical hazards to personnel, and operational shutdowns that can cost hundreds of thousands of dollars per day.
Technical Department
on25/02/2026

Splicing Type MMV (37-105) 8kV Cables: Managing Tape and Braided Shields Offshore with Field-Proven Termination Techniques

The act of splicing a medium-voltage cable in the field—joining two cable ends after they have already been installed in a drilling derrick or FPSO electrical room—occupies a unique and critical position in offshore electrical engineering. Unlike cable terminations (where the cable end is terminated to a switchgear cabinet or transformer winding terminal), field splices create a permanently joined section within the cable run itself. This joint must perform as if it were part of the original manufactured cable, maintaining perfect electrical, mechanical, and dielectric integrity in one of the world’s most hostile environments: the vibration-laden, salt-spray-corroded, perpetually humid confines of an offshore platform. When a splice fails, it often fails catastrophically, potentially causing equipment damage, electrical hazards to personnel, and operational shutdowns that can cost hundreds of thousands of dollars per day.