Introduction: The NSHTÖU — The Cable That Runs the World’s Ports

If there is one cable designation that every port electrical engineer recognises globally, it is NSHTÖU. The TROMMELFLEX® (K) (N)SHTOEU-J is the definitive embodiment of this designation — a DIN VDE 0250-814 standard drum reeling cable with EPR 3GI3 insulation, 5GM3 neoprene construction, and the broadest configuration range of any single cable family in the Klaus Faber portfolio: 24 configurations spanning 8 cross-sections from 1.5 mm² to 150 mm², with core counts from 4 to 30, ampacities from 23 A to 404 A, and weights from 372 kg/km to 8,706 kg/km [Klaus Faber Shop — TROMMELFLEX (K) (N)SHTOEU].

The NSHTÖU designation decodes as: N (multi-core flexible), S (special design for mechanical stress), H (rubber-insulated), T (thermosetting sheath), Ö (integrated German-specification sheath), U (uniform voltage rating) [FeiChun — NSHTÖU Designation Guide]. The “-J” suffix denotes a cable with integrated protective conductor (earth). DIN VDE 0250 is recognised globally as the ultimate standard for tough rubber-sheathed flexible reeling cables [Eland Cables — DIN VDE 0250]. Prysmian Group markets the identical cable construction under the TROMMELFLEX and CORDAFLEX brand names, confirming its status as the universal industry standard [Prysmian — Low Voltage Reeling Cables Datasheet].

Technical Anatomy: DIN VDE 0250-814 Specification

Complete Configuration Matrix: 24 Configurations Across 8 Cross-Sections

EPR 3GI3 + 5GM3: The Proven Insulation and Sheath System

The TROMMELFLEX (K) uses the same EPR 3GI3 insulation as the premium URSUS VS — the highest-grade ethylene propylene rubber compound in the German specification system, providing 90°C continuous operating temperature and 250°C short-circuit survival [FeiChun — 3GI3 EPR Compound Analysis]. Prysmian’s own datasheet confirms the insulation as rubber compound type 3GI3 per DIN VDE 0207-20 [Prysmian — TROMMELFLEX Specification].

The inner and outer sheaths use Gummi 5GM3 — a polychloroprene neoprene compound per DIN VDE 0207-21. The 5GM3 grade provides the core neoprene benefits (flame retardancy, oil resistance, ozone resistance, UV stability) at a specification level optimised for “medium mechanical stresses” — lighter and more flexible than the premium 5GM5 used in the URSUS family. This optimisation makes the TROMMELFLEX more economical to manufacture and easier to handle during installation, while still providing the environmental resistance certifications (flame per IEC 60332-1-2, oil, UV, water, outdoor use) required for port and industrial crane applications. The black sheath colour distinguishes it visually from the yellow URSUS and TRATOSLIGHT cables.

Core Architecture: Central Filler, Short Lay, and No Kevlar

The TROMMELFLEX (K) uses a central filler made of plastic or textile (covered with rubber if necessary), with cores twisted at short length of lay. This is fundamentally different from the Kevlar® self-supporting core used in TRATOSLIGHT and URSUS cables. The central filler provides dimensional stability and geometric uniformity to the core assembly but does not carry gravitational load — the cable cannot support its own weight in free-hanging vertical suspension.

The short-lay stranding is critical for reeling performance. Cores twisted at short lay lengths create a compact, tightly interlocked assembly that resists the internal component migration and loosening that occurs during repeated drum bending. As Feichun’s engineering analysis documents, the precisely optimised stranding pitch equalises tensile stress across all cores during dynamic bending, preventing individual conductor fatigue that would occur if some cores experienced systematically higher bending strain than others [FeiChun — 24G2.5 Stranding Pitch Engineering].

15 N/mm² Conductor Tensile: The Engineering Design Limit

The TROMMELFLEX (K) specifies a maximum tensile strength at the conductor of 15 N/mm². This unique specification (not listed on TRATOSLIGHT or URSUS datasheets) defines the maximum pulling force the cable can withstand expressed as stress per unit cross-sectional area of copper. For a 04×150 cable (600 mm² total copper), this translates to 15 × 600 = 9,000 N maximum pulling force — matching the 9,000 N Fzp listed in the configuration table. For a 07×1.5 cable (10.5 mm² total copper), the limit is 15 × 10.5 = approximately 158 N — again matching the table.

This 15 N/mm² specification gives engineers a universal formula: Fzp = 15 × (number of cores × cross-section). This allows immediate calculation of the maximum tensile for any configuration, including custom configurations not listed in the standard table. The 15 N/mm² limit represents the stress at which the tinned copper conductors begin to yield (permanently stretch) under sustained tension — the Fzp values in the table are simply 15 N/mm² applied to each configuration’s total copper cross-section.

120 m/min: The Standard Speed for Horizontal Drum Reeling

The TROMMELFLEX (K) is rated for 120 m/min operating speed — the industry-standard speed for horizontal motorised drum reeling on STS crane trolley travel, RTG gantry travel, and conveyor cable management systems. This speed matches the typical trolley traverse speeds on STS cranes (60–120 m/min) and the gantry travel speeds on RTG/RMG cranes (60–135 m/min).

The 120 m/min rating is deliberately conservative compared to the 240 m/min URSUS VS PLUS and 300 m/min TRATOSLIGHT cables. At 120 m/min, the cable’s 5GM3 neoprene sheath operates well within its thermal and mechanical limits during sustained reeling — producing less friction heat at the drum flange contact points and experiencing lower bending fatigue stress at the departure point. This conservative speed rating contributes to the TROMMELFLEX’s exceptional service life in continuous-duty applications where the cable reels thousands of times per year over a 15–20 year crane lifetime.

Application Map: Which Configuration for Which Crane Circuit?

A typical STS crane uses multiple TROMMELFLEX (K) cables on its trolley travel reel: one or two power cables (04×70 to 04×150) for the hoist and trolley motors, plus one or more control cables (24×2.5 or 30×2.5) for PLC signals, interlocks, and auxiliary circuits. The standardised DIN VDE 0250-814 construction ensures all cables on the same reel system have compatible bending characteristics, environmental resistance, and service life — simplifying maintenance and procurement across the crane’s entire cable inventory.

TROMMELFLEX vs. URSUS vs. TRATOSLIGHT: When Each Family Applies

Choose TROMMELFLEX (K) for: all standard horizontal drum reeling applications at ≤120 m/min where the cable is managed by a motorised reel (not free-hanging). This covers the vast majority of crane cable circuits including trolley/gantry travel power, auxiliary motor power, control signals, and lighting. Choose URSUS VS / VS PLUS for: vertical drum reeling with self-supporting requirement under very high mechanical stress, or applications requiring premium 5GM5 environmental protection. Choose TRATOSLIGHT VR / VRDB for: high-speed (300 m/min) vertical spreader reel applications requiring self-supporting Kevlar® construction and cross-linked elastomer sheath.

Cost-Effective Alternative from Feichun

Feichun Lead Times: 4–8 weeks for standard configurations (most in stock). European (Klaus Faber/Prysmian): 12–20 weeks.

Feichun Pricing Examples: Klaus Faber TROMMELFLEX (K) 24×2.5 quoted at €8–12/m; Feichun equivalent: €4.50–6.50/m. 04×95 quoted at €32–45/m; Feichun: €17–25/m. 04×150 quoted at €52–68/m; Feichun: €28–38/m.

Technical FAQ

What is the difference between TROMMELFLEX (K) and the standard NSHTOEU?

Klaus Faber sells both: TROMMELFLEX (K) (N)SHTOEU is the standard NSHTÖU cable with polyester braid torsion protection and ±50°/m torsion rating; the separate “Rubber reeling cable NSHTOEU” listing on the Klaus Faber shop is described as having “special construction for special applications” [Klaus Faber — NSHTOEU Special]. The TROMMELFLEX (K) is the standard specification for general-purpose drum reeling.

Why −25°C moving instead of −30°C or −40°C?

The 5GM3 neoprene sheath is slightly less cold-flexible than the 5GM5 grade used in URSUS (−30°C moving) or the cross-linked elastomer used in TRATOSLIGHT-VR (−40°C moving). For the vast majority of global port terminals (which operate above −20°C), the −25°C moving rating is fully adequate. For arctic terminals requiring colder dynamic ratings, specify URSUS VS PLUS (−30°C) or TRATOSLIGHT-VR (−40°C).

Can I use TROMMELFLEX (K) on a spring-driven reel?

Yes. Unlike the heavier URSUS cables that require motorised reels, the lighter TROMMELFLEX (K) configurations (1.5–6 mm²) can operate on spring-driven cable reels where the spring provides constant cable tension. Stemmann-Technik and other reel manufacturers supply spring-driven reels specifically designed for NSHTÖU cables in this weight range.

Is the (K) designation mandatory?

The “(K)” in the name indicates “Kabeltrommeln” (cable drums) — designating the cable as optimised for drum reeling. The cable can also be used in other managed-tension applications (festoon systems with appropriate guide rollers, drag cable applications) within its 120 m/min and 15 N/mm² limits.