600V Ethylene Propylene Rubber Insulated, Polychloroprene Rubber Sheathed Cable with Tinned Copper Wire Braided Combined with Cotton Yarn EMI Shielding and Kevlar® Aramid Fibre Tensile Reinforcement — Engineered for VFD-Driven Port Gantry Cranes, Ship-to-Shore Unloaders, Container Handling Systems, and Noise-Sensitive Curtain & Festoon Applications in Marine Terminal Environments
Japanese-Standard EMI-Shielded High-Performance Cable Engineering: Tinned Copper Annealed Conductors, EP Rubber Dielectric Insulation, Tinned Copper Wire Braided Combined with Cotton Yarn Shielding for Electromagnetic Interference Suppression and Variable Frequency Drive Compatibility, Kevlar® Para-Aramid Braided Tensile Reinforcement for Dynamic Load Absorption, Polychloroprene Rubber Outer Sheath for Oil, UV, and Saltwater Resistance, Single-Core to 30-Core Configurations from 0.75 mm² to 200 mm², and Purpose-Built for the Extreme Electrical and Mechanical Demands of Modern VFD-Controlled Port Crane Operations
600V 2TC Light-SB (2PNCT-SB) Shielded Crane Cable
600V Ethylene Propylene Rubber Insulated, Polychloroprene Rubber Sheathed Cable with Tinned Copper Wire Braided Combined with Cotton Yarn EMI Shielding and Kevlar® Aramid Fibre Tensile Reinforcement — Engineered for VFD-Driven Port Gantry Cranes, Ship-to-Shore Unloaders, Container Handling Systems, and Noise-Sensitive Curtain & Festoon Applications in Marine Terminal Environments
Japanese-Standard EMI-Shielded High-Performance Cable Engineering: Tinned Copper Annealed Conductors, EP Rubber Dielectric Insulation, Tinned Copper Wire Braided Combined with Cotton Yarn Shielding for Electromagnetic Interference Suppression and Variable Frequency Drive Compatibility, Kevlar® Para-Aramid Braided Tensile Reinforcement for Dynamic Load Absorption, Polychloroprene Rubber Outer Sheath for Oil, UV, and Saltwater Resistance, Single-Core to 30-Core Configurations from 0.75 mm² to 200 mm², and Purpose-Built for the Extreme Electrical and Mechanical Demands of Modern VFD-Controlled Port Crane Operations
Introduction: The Shielded Cable Modern Port Cranes Require
The electrification of port crane operations has undergone a fundamental transformation over the past two decades. Where earlier-generation cranes used simple contactors and resistor banks to control motor speed, virtually every modern port gantry crane, ship-to-shore (STS) unloader, and rubber-tyred gantry (RTG) crane now uses variable frequency drives (VFDs) to achieve precise, energy-efficient motor control. VFDs convert fixed-frequency AC power to variable-frequency, variable-voltage output using high-speed insulated-gate bipolar transistor (IGBT) switching—typically at carrier frequencies of 2–16 kHz. This switching produces steep voltage pulses (dV/dt rates exceeding 5,000 V/µs) that radiate intense electromagnetic interference (EMI) across a broad frequency spectrum from 10 kHz to 30 MHz.
In a port crane environment, this radiated and conducted EMI creates real operational problems. Unshielded power cables carrying VFD output act as antennas, broadcasting interference that corrupts nearby control signals, encoder feedback, communication buses (PROFINET, PROFIBUS, CAN, Modbus), and safety system circuits. The consequences range from intermittent positioning errors and spurious fault trips to complete loss of motor control—any of which can halt crane operations or, in worst cases, create dangerous uncontrolled loads. The problem is amplified in festoon and curtain cable systems where power and control cables run in close proximity for distances of 50–150 metres.
The 600V 2TC Light-SB (600V 2PNCT-SB) cable solves this problem. Built on the same proven JIS C 3327 platform as the unshielded 2TC Light, it adds a critical engineering layer: a tinned copper wire braided combined with cotton yarn shielding that surrounds the insulated conductor bundle. This hybrid metallic/textile braid provides effective EMI containment across the full VFD emission spectrum, preventing radiated noise from escaping power cables and protecting control cables from external interference. Combined with the Kevlar® para-aramid fibre braided tensile reinforcement for mechanical load bearing, the 2TC Light-SB delivers both electromagnetic cleanliness and structural durability in a single cable design purpose-built for the electrical and mechanical demands of modern VFD-controlled port cranes.
When VFD-driven motors are connected via long cable runs (>30 metres) in crane festoon or reeling systems, shielded cables are not optional—they are an engineering necessity. Unshielded VFD output cables in these installations will radiate sufficient EMI to interfere with adjacent control, communication, and safety circuits. The resulting operational disruptions can cause crane downtime, positioning errors, and safety system malfunctions. All VFD output cables in crane festoon and reeling systems should be shielded, with the shield properly grounded at both ends using 360° low-impedance connections. Consult Feichun’s engineering team for project-specific EMC design guidance.
Technical Specifications: JIS C 3327 with EMI Shielding
| Parameter | Specification |
|---|---|
| Standard Compliance | JIS C 3327 (Japanese Industrial Standard for cabtyre cables). Equivalent: Feichun FC-2PNCT-SB-K™ Series. |
| Voltage Rating | 600V. Test voltage: 3,000V / 1 min. |
| Cable Designation | 600V 2TC Light-SB (600V 2PNCT-SB) — low voltage power with shielding, EP rubber insulated, polychloroprene rubber sheathed. |
| Conductor Material | Tin-coated annealed copper strand wire. Superior corrosion resistance in saltwater marine environments. |
| Insulation Material | Ethylene propylene rubber (EP rubber). Excellent dielectric strength, heat resistance, and flexibility retention. |
| Shielding | Tinned copper wire braided combined with cotton yarn. Shield strand diameters: 0.12 mm, 0.16 mm, or 0.18 mm depending on cable size. Provides EMI containment across 10 kHz–30 MHz. |
| Tensile Reinforcement | Kevlar® para-aramid fibre braided layer. Proprietary helical braid pattern. 5× stronger than steel per unit weight. |
| Outer Sheath | Polychloroprene rubber (CR rubber). Oil-resistant, flame-retardant, UV-stable, saltwater-resistant. |
| Core Count | Single core (1.25–200 mm²); 2–4 cores (0.75–38 mm²); 5–30 cores (1.25–3.5 mm²). |
| Primary Applications | VFD-driven port cranes, STS ship unloaders, EMI-sensitive crane control systems, shielded festoon/curtain/reeling cable systems. |
| Temperature Range | −30°C to +80°C (continuous operation). Short-circuit: 200°C. |
| Bending Radius (Dynamic) | 6× OD minimum for festoon/reeling applications. |
| Bending Radius (Fixed) | 4× OD minimum for static installations. |
| Flex Life (Typical) | >1,000,000 cycles at rated bending radius (laboratory conditions, 25°C). |
| EMC Performance | Effective shielding across VFD emission spectrum (10 kHz–30 MHz). Shield transfer impedance typically <100 mΩ/m at 1 MHz. |
Tinned Copper / Cotton Yarn Braid Shield: EMI Defence Engineering
The defining engineering feature that distinguishes the 2TC Light-SB from the standard 2TC Light is the tinned copper wire braided combined with cotton yarn shielding layer. This is not a simple foil wrap or loose screen—it is a precision-braided hybrid shield that combines the electromagnetic shielding effectiveness of metallic conductor braids with the mechanical flexibility and dimensional stability of textile interlacing.
Hybrid Braid Construction
The shield is constructed by braiding fine tinned copper wires (0.12 mm, 0.16 mm, or 0.18 mm diameter, depending on cable size) together with cotton yarn carriers on a high-speed tubular braiding machine. The tinned copper wires provide the electrical conductivity required for EMI interception and shunting to ground. The cotton yarn carriers serve three critical engineering functions: they maintain consistent braid geometry during repeated cable flexing (preventing metallic wire bunching and gap formation), they provide inter-wire cushioning that prevents copper-to-copper abrasion during dynamic bending cycles, and they contribute to the shield’s overall flexibility by acting as textile hinges between the rigid metallic braid segments.
The tin coating on the copper shield wires is essential for port terminal applications. Bare copper braid would oxidise rapidly in saltwater-spray marine environments, forming a copper oxide surface layer that increases contact resistance between overlapping braid wires and degrades shielding effectiveness. Tin provides a sacrificial corrosion barrier that maintains low-resistance wire-to-wire contact points throughout the cable’s operational life, ensuring consistent shield performance over 10–15+ years of marine exposure.
Shielding Mechanism: How the Braid Stops EMI
Electromagnetic interference propagates in two modes: radiated EMI (electromagnetic waves travelling through air) and conducted EMI (high-frequency noise currents travelling along cable conductors). The tinned copper/cotton braid shield addresses both modes simultaneously.
For radiated EMI, the metallic braid acts as a Faraday cage surrounding the cable’s conductor bundle. When an electromagnetic wave strikes the braid surface, it induces circulating currents (eddy currents) in the tinned copper wires. These eddy currents generate a counter-electromagnetic field that opposes and largely cancels the incoming wave—the same physical principle used in Faraday cages, anechoic chambers, and shielded enclosures. The braid’s optical coverage (typically 70–85% of the cable surface area) determines the upper frequency limit of effective shielding. At frequencies below approximately 10 MHz, the braid provides >40 dB of attenuation. At higher frequencies (10–30 MHz), attenuation remains >25 dB—sufficient to reduce VFD-generated EMI to levels that do not interfere with adjacent control circuits.
For conducted EMI, the shield provides a low-impedance return path for common-mode noise currents. VFD output cables carry both the intended motor current (differential mode) and parasitic high-frequency currents generated by IGBT switching (common mode). Without a shield, these common-mode currents return through unpredictable paths—cable trays, crane structures, earth connections—creating interference in any circuit that shares these return paths. With the braid shield properly grounded at both ends, common-mode currents are captured and returned via the controlled, low-impedance shield path, preventing them from coupling into adjacent circuits.
Aluminium foil shields are common in building wiring and static data cables, but they are fundamentally unsuitable for dynamic crane cable applications. Foil shields are rigid—they crack and fracture after relatively few bending cycles, creating gaps in the electromagnetic barrier that render the shield ineffective. The fatigue life of aluminium foil under repeated flexing is typically <10,000 cycles—two orders of magnitude below the >1,000,000 cycle requirement for crane festoon cables. The tinned copper/cotton braid shield, by contrast, is inherently flexible. The interlocking braid geometry allows individual wires to slide relative to each other during bending, distributing mechanical stress without wire breakage. The cotton yarn carriers maintain braid integrity by preventing wire bunching. The result is a shield that maintains full electromagnetic effectiveness after millions of flex cycles—matching the mechanical endurance of the cable itself.
Kevlar® Aramid Braided Tensile Reinforcement: Mechanical Backbone
Like its unshielded counterpart, the 2TC Light-SB incorporates a Kevlar® para-aramid fibre braided tensile reinforcement layer—the same bulletproof-vest-grade material that provides the cable’s extraordinary mechanical performance in dynamic crane applications. Kevlar® delivers a tensile strength of approximately 3,620 MPa at a density of only 1.44 g/cm³, making it roughly five times stronger than steel on a weight-for-weight basis.
The Kevlar® layer is braided into a continuous tubular reinforcement using a proprietary helical weave pattern with controlled lay angles (typically 35–55° relative to the cable axis). This engineered braid geometry balances axial tensile strength with lateral flexibility—providing high load capacity along the cable axis while maintaining the bending compliance required for festoon, reeling, and curtain applications. In a typical port crane festoon installation where the cable hangs in catenary loops across spans of 50–150 metres, the Kevlar® braid absorbs the cable’s self-weight plus dynamic acceleration and deceleration forces before they reach the copper conductors or the delicate shield braid. This mechanical decoupling is especially critical in the shielded variant—without tensile reinforcement, dynamic loads would compress and distort the shield braid, creating gaps in the electromagnetic barrier and degrading EMI performance.
The Kevlar® reinforcement also serves as a shock absorber during transient events such as emergency stops, wind gusts, and load collisions. The braided geometry allows micro-deformation under shock loading that dissipates energy without permanent deformation of the aramid fibres, the shield braid, or the copper conductors. This gives the cable its rated flex life of over one million cycles under laboratory conditions and its typical field service life of 12–15 years in continuous STS crane operation.
In a shielded crane cable, the tensile reinforcement layer serves double duty. Beyond protecting the conductors from mechanical stress (as in the unshielded 2TC Light), it also protects the shield braid from deformation. Shield braid effectiveness depends on maintaining consistent braid geometry and uniform optical coverage. If external tensile or compressive forces distort the braid (stretching it open under tension, or crushing it under clamp pressure), gaps form in the metallic coverage and shielding effectiveness degrades. The Kevlar® layer intercepts these forces before they reach the shield, ensuring the tinned copper/cotton braid maintains its designed geometry and electromagnetic performance throughout the cable’s service life. This is why shielded crane cables without proper tensile reinforcement often show declining EMI performance after just 1–2 years of service—the unprotected shield is mechanically degraded by crane operation forces.
Cable Construction: Layer-by-Layer Analysis
The 2TC Light-SB (2PNCT-SB) cable comprises six distinct functional layers, each engineered to serve a specific electrical, mechanical, or environmental protection function. From the cable centre outward:
Layer 1 — Conductor: Tin-coated annealed copper strand wire. The tin coating resists corrosion in marine environments. Annealing maximises ductility for repeated bending. Fine-stranded construction distributes bending stress across many wire contact points. Strand configurations range from 30/0.18 (0.75 mm² conductors) to 37/34/0.45 (200 mm² conductors).
Layer 2 — Separator: A thin separator tape wraps each conductor, preventing EP rubber from bonding to the copper surface. This allows free conductor movement within the insulation tube during bending—preventing insulation cracking and conductor fatigue.
Layer 3 — EP Rubber Insulation: Ethylene propylene rubber provides the primary dielectric barrier. EP rubber maintains flexibility at −30°C, resists ozone cracking, and retains dielectric strength after millions of flex cycles. Insulation thickness: 0.8 mm (small conductors) to 2.5 mm (large conductors).
Layer 4 — Fillers & Binder Tape: In multi-core configurations, non-hygroscopic fillers fill the interstices between insulated cores to create a circular cross-section. A binder tape wraps the assembled core bundle to maintain geometry during subsequent manufacturing steps.
Layer 5 — Tinned Copper / Cotton Yarn Braid Shield: The hybrid EMI shield described above. Applied over a second binder tape layer. Shield wire diameter: 0.12 mm for cables ≤14 mm², 0.16 mm for 22–60 mm² cables, 0.18 mm for ≥80 mm² cables. The progressive increase in shield wire diameter ensures adequate shield current-carrying capacity as motor current (and therefore EMI magnitude) increases with cable size.
Layer 6 — Kevlar® Aramid Braided Tensile Layer: The proprietary helical-braided aramid reinforcement layer. Applied over the shield braid with controlled tension. Provides the structural backbone for the entire cable assembly.
Layer 7 — Polychloroprene Rubber Sheath: The outer protective sheath. Provides environmental defence against oil, UV, saltwater, abrasion, and flame. Sheath thickness: 1.6 mm (small single-core) to 3.3 mm (large multi-core).
The specification uses three different shield wire diameters (0.12 mm, 0.16 mm, and 0.18 mm) that increase with conductor cross-section. This is not arbitrary—larger conductor cables carry higher motor currents, which generate proportionally stronger electromagnetic fields. The thicker shield wires in larger cables provide lower shield resistance (better common-mode current handling) and higher mechanical robustness (better fatigue resistance under the greater bending forces experienced by larger-diameter cables). This progressive sizing ensures optimal EMI performance and mechanical durability across the entire product range.
Why VFD-Driven Cranes Demand Shielded Cables
Understanding why shielded cables are essential for modern port cranes requires understanding how variable frequency drives generate electromagnetic interference. A VFD converts fixed-frequency mains power (50/60 Hz) to variable-frequency output (typically 0–120 Hz) using pulse-width modulation (PWM). The output stage uses IGBT transistors that switch the DC bus voltage on and off at carrier frequencies of 2–16 kHz, creating a synthesised AC waveform from a rapid succession of voltage pulses.
Each switching event produces a voltage pulse with an extremely fast rise time—typically 50–200 nanoseconds, corresponding to dV/dt rates of 3,000–10,000 V/µs. These steep voltage transitions contain harmonic energy spanning from the carrier frequency (2–16 kHz) through tens of megahertz. The cable connecting the VFD output to the motor acts as a transmission line for this high-frequency energy. Without shielding, the cable radiates this energy into the surrounding environment as electromagnetic waves, and conducts it along the cable’s parasitic capacitance as common-mode current.
The Crane Environment Amplifies the Problem
Port cranes create the worst possible conditions for EMI propagation. VFD output cables run alongside control cables, encoder cables, and communication buses in shared festoon carrier systems for distances of 50–150 metres—providing extensive coupling length for interference transfer. The steel crane structure acts as a resonant cavity that reflects and amplifies electromagnetic waves. Multiple VFDs operating simultaneously (hoist, trolley, boom, gantry drives) create additive interference from multiple sources. The long cable runs between VFD and motor create significant antenna gain for radiated emissions.
The practical consequences of operating VFD-driven crane motors with unshielded cables include: encoder feedback errors causing positioning inaccuracy, PROFINET/PROFIBUS communication dropouts that trigger drive faults, spurious safety system activations that halt crane operation, bearing current damage in motors (caused by common-mode voltage coupling through motor shaft), and radio-frequency interference that violates port electromagnetic compatibility (EMC) regulations.
The 2TC Light-SB cable eliminates these problems by containing VFD emissions within the shielded cable structure and preventing external interference from coupling into sensitive control cables.
EP Rubber Insulation & Polychloroprene Sheath
The 2TC Light-SB uses the same insulation and sheath materials as the unshielded 2TC Light, selected specifically for the demanding port crane environment.
EP Rubber Insulation provides the primary dielectric barrier with a dielectric strength of 20–30 kV/mm—giving a safety margin of 25–100× the 600V rating. EP rubber maintains full flexibility down to −30°C, resists ozone cracking (critical in marine environments where ozone concentration is elevated), and absorbs the cyclic bending deformation inherent in festoon and reeling applications without developing micro-cracks. The minimum insulation resistance values specified by JIS C 3327 range from 200 MΩ·km to 500 MΩ·km at 20°C.
Polychloroprene Rubber Sheath provides the external environmental armour. Polychloroprene’s unique combination of oil resistance, flame retardancy, UV stability, ozone resistance, saltwater impermeability, and mechanical abrasion resistance makes it the undisputed industry standard for crane cable outer sheaths. The material is inherently self-extinguishing—a critical safety requirement in confined crane cable tray environments. In the shielded 2TC Light-SB variant, the polychloroprene sheath also serves as mechanical protection for the underlying shield braid, preventing external abrasion from wearing through the shield layer.
Wire Core Identification & Configuration Options
| Core Count | Colour Assignment |
|---|---|
| 2 core | Black, White |
| 3 core | Black, White, Red |
| 4 core | Black, White, Red, Green |
| 5 core | Black, White, Red, Green, Yellow |
| 6 core | Black, White, Red, Green, Yellow, Blue |
| 7+ core | Based on combination of the 6 standard colours |
The 2TC Light-SB is available in single-core configurations from 1.25 mm² to 200 mm² for shielded high-current VFD output and power distribution, multi-core configurations (2, 3, and 4 cores) from 0.75 mm² to 38 mm² for standard three-phase motor connections and shielded control power, and high core-count configurations (5 to 30 cores) in 1.25 mm², 2 mm², and 3.5 mm² for shielded control, signal, and instrumentation applications. The shielded variant covers a slightly narrower range than the unshielded 2TC Light (200 mm² maximum for single-core versus 325 mm², and 38 mm² maximum for multi-core versus 150 mm²), reflecting the practical requirement that the shield braid diameter must increase with cable size to maintain adequate EMI coverage.
Dimensional & Electrical Data: Single Core (1.25–200 mm²)
| mm² | Conductor | Cond. ⌀ (mm) | EP Ins. (mm) | Shield ⌀ (mm) | CR Sheath (mm) | Overall ⌀ (mm) | Max. ⌀ (mm) | Weight (kg/km) | Max. RDC 20°C (Ω/km) | Test V (V/1 min) | Min. IR 20°C (MΩ·km) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1.25 | 50/0.18 | 1.5 | 0.8 | 0.12 | 1.6 | 7.5 | 8.5 | 80 | 15.5 | 3000 | 500 |
| 2 | 37/0.26 | 1.8 | 0.8 | 0.12 | 1.6 | 7.8 | 8.8 | 90 | 9.91 | 3000 | 500 |
| 3.5 | 45/0.32 | 2.5 | 0.8 | 0.12 | 1.7 | 8.7 | 9.7 | 115 | 5.38 | 3000 | 400 |
| 5.5 | 70/0.32 | 3.1 | 1.0 | 0.12 | 1.7 | 9.7 | 10.7 | 150 | 3.46 | 3000 | 400 |
| 8 | 50/0.45 | 3.7 | 1.0 | 0.12 | 1.8 | 10.5 | 11.5 | 190 | 2.45 | 3000 | 400 |
| 14 | 88/0.45 | 4.9 | 1.0 | 0.12 | 1.8 | 11.8 | 12.8 | 265 | 1.39 | 3000 | 300 |
| 22 | 7/20/0.45 | 6.7 | 1.2 | 0.12 | 2.0 | 14.7 | 15.7 | 410 | 0.892 | 3000 | 300 |
| 38 | 7/34/0.45 | 9.1 | 1.2 | 0.16 | 2.1 | 17.2 | 18.2 | 620 | 0.525 | 3000 | 200 |
| 60 | 19/20/0.45 | 11.2 | 1.5 | 0.16 | 2.4 | 21 | 22 | 925 | 0.329 | 3000 | 200 |
| 80 | 19/27/0.45 | 13.0 | 2.0 | 0.18 | 2.5 | 24 | 25 | 1240 | 0.243 | 3000 | 200 |
| 100 | 19/34/0.45 | 14.7 | 2.0 | 0.18 | 2.7 | 26 | 28 | 1500 | 0.193 | 3000 | 200 |
| 150 | 27/34/0.45 | 17.7 | 2.0 | 0.18 | 2.9 | 30 | 31 | 2020 | 0.136 | 3000 | 200 |
| 200 | 37/34/0.45 | 20.0 | 2.5 | 0.18 | 3.1 | 34 | 35 | 2690 | 0.0993 | 3000 | 200 |
Dimensional & Electrical Data: Multi-Core (2–4 Cores)
| mm² | Conductor | Cond. ⌀ (mm) | EP Ins. (mm) | Shield ⌀ (mm) | CR Sheath (mm) | Overall ⌀ (mm) | Max. ⌀ (mm) | Weight (kg/km) | Max. RDC (Ω/km) | Test V | Min. IR (MΩ·km) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 0.75 | 30/0.18 | 1.1 | 0.8 | 0.12 | 1.8 | 10.8 | 11.8 | 140 | 27.0 | 3000 | 500 |
| 1.25 | 50/0.18 | 1.5 | 0.8 | 0.12 | 1.8 | 11.6 | 12.6 | 165 | 16.2 | 3000 | 500 |
| 2 | 37/0.26 | 1.8 | 0.8 | 0.12 | 1.9 | 12.4 | 13.4 | 195 | 10.4 | 3000 | 500 |
| 3.5 | 45/0.32 | 2.5 | 0.8 | 0.12 | 2.0 | 14.0 | 15.0 | 260 | 5.65 | 3000 | 400 |
| 5.5 | 70/0.32 | 3.1 | 1.0 | 0.16 | 2.1 | 16.4 | 17.4 | 365 | 3.63 | 3000 | 400 |
| 8 | 50/0.45 | 3.7 | 1.0 | 0.16 | 2.2 | 17.8 | 18.8 | 445 | 2.57 | 3000 | 400 |
| 14 | 88/0.45 | 4.9 | 1.0 | 0.16 | 2.4 | 21 | 22 | 640 | 1.46 | 3000 | 300 |
| 22 | 7/20/0.45 | 6.7 | 1.2 | 0.18 | 2.7 | 27 | 28 | 1030 | 0.936 | 3000 | 300 |
| 38 | 7/34/0.45 | 9.1 | 1.2 | 0.18 | 2.9 | 31 | 33 | 1490 | 0.541 | 3000 | 200 |
| mm² | Conductor | Cond. ⌀ (mm) | EP Ins. (mm) | Shield ⌀ (mm) | CR Sheath (mm) | Overall ⌀ (mm) | Max. ⌀ (mm) | Weight (kg/km) | Max. RDC (Ω/km) | Test V | Min. IR (MΩ·km) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 0.75 | 30/0.18 | 1.1 | 0.8 | 0.12 | 1.8 | 11.2 | 12.2 | 155 | 27.0 | 3000 | 500 |
| 1.25 | 50/0.18 | 1.5 | 0.8 | 0.12 | 1.9 | 12.3 | 13.3 | 195 | 16.2 | 3000 | 500 |
| 2 | 37/0.26 | 1.8 | 0.8 | 0.12 | 1.9 | 12.9 | 13.9 | 225 | 10.4 | 3000 | 500 |
| 3.5 | 45/0.32 | 2.5 | 0.8 | 0.12 | 2.0 | 14.7 | 15.7 | 310 | 5.65 | 3000 | 400 |
| 5.5 | 70/0.32 | 3.1 | 1.0 | 0.16 | 2.2 | 17.4 | 18.4 | 450 | 3.63 | 3000 | 400 |
| 8 | 50/0.45 | 3.7 | 1.0 | 0.16 | 2.3 | 18.9 | 19.9 | 560 | 2.57 | 3000 | 400 |
| 14 | 88/0.45 | 4.9 | 1.0 | 0.16 | 2.4 | 22 | 23 | 815 | 1.46 | 3000 | 300 |
| 22 | 7/20/0.45 | 6.7 | 1.2 | 0.18 | 2.8 | 29 | 30 | 1330 | 0.936 | 3000 | 300 |
| 38 | 7/34/0.45 | 9.1 | 1.2 | 0.18 | 3.1 | 34 | 35 | 1970 | 0.541 | 3000 | 200 |
| mm² | Conductor | Cond. ⌀ (mm) | EP Ins. (mm) | Shield ⌀ (mm) | CR Sheath (mm) | Overall ⌀ (mm) | Max. ⌀ (mm) | Weight (kg/km) | Max. RDC (Ω/km) | Test V | Min. IR (MΩ·km) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 0.75 | 30/0.18 | 1.1 | 0.8 | 0.12 | 1.9 | 12.2 | 13.2 | 185 | 27.0 | 3000 | 500 |
| 1.25 | 50/0.18 | 1.5 | 0.8 | 0.12 | 1.9 | 13.1 | 14.1 | 225 | 16.2 | 3000 | 500 |
| 2 | 37/0.26 | 1.8 | 0.8 | 0.12 | 2.0 | 14.0 | 15.0 | 270 | 10.4 | 3000 | 500 |
| 3.5 | 45/0.32 | 2.5 | 0.8 | 0.16 | 2.1 | 16.1 | 17.1 | 390 | 5.65 | 3000 | 400 |
| 5.5 | 70/0.32 | 3.1 | 1.0 | 0.16 | 2.3 | 19.0 | 20 | 555 | 3.63 | 3000 | 400 |
| 8 | 50/0.45 | 3.7 | 1.0 | 0.16 | 2.4 | 21 | 22 | 690 | 2.57 | 3000 | 400 |
| 14 | 88/0.45 | 4.9 | 1.0 | 0.18 | 2.6 | 25 | 26 | 1040 | 1.46 | 3000 | 300 |
| 22 | 7/20/0.45 | 6.7 | 1.2 | 0.18 | 3.0 | 32 | 33 | 1690 | 0.936 | 3000 | 300 |
| 38 | 7/34/0.45 | 9.1 | 1.2 | 0.18 | 3.3 | 37 | 39 | 2510 | 0.541 | 3000 | 200 |
Dimensional & Electrical Data: Multi-Core (5–30 Cores)
| Cores | Conductor | Cond. ⌀ (mm) | EP Ins. (mm) | Shield ⌀ (mm) | CR Sheath (mm) | Overall ⌀ (mm) | Max. ⌀ (mm) | Weight (kg/km) | Max. RDC (Ω/km) | Test V | Min. IR (MΩ·km) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 5 | 50/0.18 | 1.5 | 0.8 | 0.12 | 2.0 | 14.2 | 15.2 | 265 | 16.2 | 3000 | 500 |
| 6 | 50/0.18 | 1.5 | 0.8 | 0.12 | 2.1 | 15.6 | 16.6 | 320 | 16.2 | 3000 | 500 |
| 7 | 50/0.18 | 1.5 | 0.8 | 0.16 | 2.1 | 16.6 | 17.6 | 360 | 16.2 | 3000 | 500 |
| 8 | 50/0.18 | 1.5 | 0.8 | 0.16 | 2.2 | 17.8 | 18.8 | 410 | 16.2 | 3000 | 500 |
| 10 | 50/0.18 | 1.5 | 0.8 | 0.16 | 2.3 | 20.0 | 21 | 500 | 16.2 | 3000 | 500 |
| 12 | 50/0.18 | 1.5 | 0.8 | 0.16 | 2.3 | 19.7 | 21 | 525 | 16.2 | 3000 | 500 |
| 16 | 50/0.18 | 1.5 | 0.8 | 0.16 | 2.4 | 22 | 23 | 645 | 16.2 | 3000 | 500 |
| 20 | 50/0.18 | 1.5 | 0.8 | 0.18 | 2.6 | 25 | 26 | 800 | 16.2 | 3000 | 500 |
| 30 | 50/0.18 | 1.5 | 0.8 | 0.18 | 2.8 | 28 | 30 | 1100 | 16.2 | 3000 | 500 |
| Cores | Conductor | Cond. ⌀ (mm) | EP Ins. (mm) | Shield ⌀ (mm) | CR Sheath (mm) | Overall ⌀ (mm) | Max. ⌀ (mm) | Weight (kg/km) | Max. RDC (Ω/km) | Test V | Min. IR (MΩ·km) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 5 | 37/0.26 | 1.8 | 0.8 | 0.16 | 2.1 | 15.5 | 16.5 | 335 | 10.4 | 3000 | 500 |
| 6 | 37/0.26 | 1.8 | 0.8 | 0.16 | 2.1 | 16.5 | 17.5 | 380 | 10.4 | 3000 | 500 |
| 7 | 37/0.26 | 1.8 | 0.8 | 0.16 | 2.2 | 17.8 | 18.8 | 440 | 10.4 | 3000 | 500 |
| 8 | 37/0.26 | 1.8 | 0.8 | 0.16 | 2.3 | 19.0 | 20 | 495 | 10.4 | 3000 | 500 |
| 10 | 37/0.26 | 1.8 | 0.8 | 0.16 | 2.4 | 22 | 23 | 575 | 10.4 | 3000 | 500 |
| 12 | 37/0.26 | 1.8 | 0.8 | 0.16 | 2.4 | 22 | 23 | 650 | 10.4 | 3000 | 500 |
| 16 | 37/0.26 | 1.8 | 0.8 | 0.18 | 2.5 | 24 | 25 | 815 | 10.4 | 3000 | 500 |
| 20 | 37/0.26 | 1.8 | 0.8 | 0.18 | 2.7 | 26 | 28 | 1000 | 10.4 | 3000 | 500 |
| 30 | 37/0.26 | 1.8 | 0.8 | 0.18 | 2.9 | 31 | 32 | 1390 | 10.4 | 3000 | 500 |
| Cores | Conductor | Cond. ⌀ (mm) | EP Ins. (mm) | Shield ⌀ (mm) | CR Sheath (mm) | Overall ⌀ (mm) | Max. ⌀ (mm) | Weight (kg/km) | Max. RDC (Ω/km) | Test V | Min. IR (MΩ·km) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 5 | 45/0.32 | 2.5 | 0.8 | 0.16 | 2.2 | 17.5 | 18.5 | 465 | 5.65 | 3000 | 400 |
| 6 | 45/0.32 | 2.5 | 0.8 | 0.16 | 2.3 | 19.0 | 20 | 545 | 5.65 | 3000 | 400 |
| 7 | 45/0.32 | 2.5 | 0.8 | 0.16 | 2.3 | 21 | 22 | 620 | 5.65 | 3000 | 400 |
| 8 | 45/0.32 | 2.5 | 0.8 | 0.16 | 2.4 | 22 | 23 | 705 | 5.65 | 3000 | 400 |
| 10 | 45/0.32 | 2.5 | 0.8 | 0.18 | 2.6 | 25 | 27 | 895 | 5.65 | 3000 | 400 |
| 12 | 45/0.32 | 2.5 | 0.8 | 0.18 | 2.6 | 25 | 26 | 960 | 5.65 | 3000 | 400 |
| 16 | 45/0.32 | 2.5 | 0.8 | 0.18 | 2.7 | 27 | 29 | 1200 | 5.65 | 3000 | 400 |
| 20 | 45/0.32 | 2.5 | 0.8 | 0.18 | 2.9 | 30 | 32 | 1480 | 5.65 | 3000 | 400 |
| 30 | 45/0.32 | 2.5 | 0.8 | 0.18 | 3.2 | 36 | 37 | 2100 | 5.65 | 3000 | 400 |
The tables above list representative sizes only. For other manufacturing sizes not listed here, or for custom configurations combining shielded power cores with shielded control cores in a single cable assembly, please contact Feichun’s engineering team directly. Composite cable designs (power + control + fibre optic in a single shielded assembly) are available on request for integrated crane cable systems.
Application Guide: VFD Cranes, Ship Unloaders & Sensitive Systems
VFD Output Cables for STS & Gantry Cranes
The primary application for the 2TC Light-SB is connecting VFD output terminals to crane motor terminals via festoon or reeling cable systems. The shielded cable contains the VFD’s high-frequency emissions within the cable structure, preventing radiated interference from corrupting adjacent control and communication cables in the same festoon carrier system. For STS cranes with multiple VFD-driven axes (hoist, trolley, boom luffing, gantry travel), every VFD output cable should be the shielded -SB variant. Typical selections: 3-core or 4-core 22–60 mm² for main drives, 3-core 8–14 mm² for auxiliary drives.
Shielded Control & Signal Cables
High core-count 2TC Light-SB cables (5–30 core, 1.25–3.5 mm²) are used for crane control circuits, encoder feedback, and analogue sensor signals that must be protected from external EMI. The shield prevents interference from VFD output cables, crane drive busbars, and external radio-frequency sources from coupling into sensitive signal conductors. This is particularly critical for encoder feedback cables (where a single corrupted pulse can cause positioning errors) and analogue sensor cables (where EMI manifests as measurement noise).
Ship Unloader Drive Systems
Modern continuous ship unloaders (CSUs) and grab-type unloaders use VFD-driven hoist, trolley, and shuttle drives. The long cable runs in these machines (often 80–200 metres from the VFD cabinet to the motor) create significant antenna lengths for EMI radiation. The 2TC Light-SB’s shield provides essential containment for these long runs, while the Kevlar® tensile reinforcement handles the mechanical demands of continuous bulk material handling operation with its inherent vibration, dust contamination, and thermal cycling.
RTG Crane Cable Reeling Systems
Rubber-tyred gantry (RTG) cranes using cable reeling for power supply increasingly employ VFDs for energy-efficient operation. The reeling cable must be shielded to prevent VFD emissions from radiating into the container yard environment (where they could interfere with terminal operating system wireless communications, GPS-based container positioning systems, and adjacent crane control systems). The 2TC Light-SB’s combination of shield integrity under drum winding forces and Kevlar® reinforcement for fatigue resistance makes it the premium choice for shielded RTG reeling applications.
Comparative field measurements at a major Southeast Asian container terminal showed that replacing unshielded VFD output cables with 2TC Light-SB shielded cables on a fleet of 12 STS cranes reduced PROFINET communication fault rates by 94%, eliminated all EMI-related drive trips, and resolved persistent encoder feedback errors that had been causing container positioning inaccuracies of 20–50 mm. The terminal reported a payback period of less than 6 months based on reduced downtime and maintenance calls alone—before accounting for the extended cable service life.
2TC Light-SB vs. 2TC Light: When Do You Need the Shield?
| Application | 2TC Light (Unshielded) | 2TC Light-SB (Shielded) |
|---|---|---|
| VFD output to motor (any cable length) | Not recommended | Required |
| Direct-on-line motor power (contactor-started) | Suitable | Not required (no VFD EMI) |
| Crane lighting circuits | Suitable | Not required |
| Control cables adjacent to VFD cables | Risk of EMI pickup | Recommended |
| Encoder & analogue sensor cables | Not recommended near VFDs | Required |
| Communication bus cables (PROFINET, CAN) | Not recommended near VFDs | Required |
| Safety system wiring (e-stop, overload) | Acceptable if separated from VFD cables | Recommended for reliability |
| Heating/HVAC circuits | Suitable | Not required |
| Weight sensitivity (weight-critical applications) | Lighter (no shield weight) | Slightly heavier (+15–25%) |
| Cost sensitivity (budget-constrained projects) | Lower cost | Higher cost (+20–30%) |
The general rule is straightforward: any cable that carries VFD output, or any cable that runs alongside VFD output cables, should be shielded. The cost premium of the shielded variant (typically 20–30% over the unshielded equivalent) is negligible compared to the cost of EMI-related crane downtime, troubleshooting, and the eventual retrofit that will be required when unshielded cables cause persistent interference problems.
Installation Best Practices for Shielded Crane Cables
Shield Grounding: The Most Critical Detail
The effectiveness of any shielded cable depends entirely on correct shield grounding. The shield must be connected to the equipotential bonding system (earth/ground) at both ends of the cable using 360° low-impedance connections. This means the shield braid should be terminated using EMC cable glands (also called shielded glands or 360° glands) that provide a continuous metallic contact between the shield braid and the gland body, which is in turn bolted to the earthed enclosure (VFD cabinet, motor junction box, or intermediate junction box). Never use pigtail connections (a single wire stripped from the shield braid and screwed to a terminal). Pigtail connections introduce inductance that renders the shield ineffective at frequencies above approximately 1 MHz—exactly the frequency range where VFD EMI is most problematic.
Festoon System Design for Shielded Cables
When installing shielded cables in festoon carrier systems, maintain a minimum separation distance of 200 mm between shielded VFD power cables and unshielded control cables. If this separation is not physically possible in the carrier trolley, then all cables in the system should be shielded. Festoon carrier trolleys should use non-metallic saddles (nylon or UHMWPE) to prevent shield damage from abrasive contact with carrier hardware. Inspect saddles every 6 months for wear that could create sharp edges.
Reeling Drum Considerations
For shielded cables on reeling drums, verify that the cable entry brush gear or slip ring assembly provides a continuous shield connection from the cable shield to the crane’s earthing system. Loss of shield continuity at the reeling drum interface negates the entire cable’s shielding performance. Use rotary EMC connectors or spring-loaded shield contact brushes rated for the drum’s rotational speed and operational cycles.
Shield Continuity Testing
After installation, measure the shield resistance end-to-end using a low-resistance ohmmeter. Shield resistance should not exceed 50 mΩ/m for new installations. Repeat this measurement annually. An increasing shield resistance trend indicates shield damage (wire breakage from mechanical fatigue, corrosion, or abrasion) and predicts declining EMI performance. Plan cable replacement when shield resistance exceeds 200 mΩ/m.
Technical FAQ
What is the weight penalty of the shielded variant compared to the unshielded 2TC Light?
The shield adds approximately 15–25% to the cable weight compared to the equivalent unshielded 2TC Light configuration. For example, a 3-core 14 mm² unshielded cable weighs approximately 825 kg/km, while the shielded variant weighs 815 kg/km (in this specific size, the slightly different construction balances out). For larger sizes, the weight difference becomes more noticeable. The Kevlar® tensile reinforcement easily accommodates this additional self-weight in festoon applications, and the weight penalty is far less than steel wire armour alternatives.
Can the shield carry fault current?
The tinned copper braid shield has a defined current-carrying capacity that depends on the shield wire diameter and braid coverage. For short-circuit fault current applications, the shield’s cross-sectional area should be verified against the prospective fault current and disconnection time using IEC 60364-5-54 calculations. In most crane applications, the shield is not relied upon as a protective earth conductor—a separate PE conductor is used. Contact Feichun for shield cross-section data and fault current calculations for specific cable sizes.
Is the shield effective against lightning-induced surges?
The braid shield provides limited protection against lightning-induced transients. For crane installations in high-lightning-risk areas (tropical ports, exposed quay locations), dedicated surge protection devices (SPDs) should be installed at both ends of the cable in addition to the cable shield. The shield attenuates coupled transients but cannot fully clamp the energy from a nearby lightning strike.
What VFD carrier frequencies is the shield effective against?
The tinned copper/cotton yarn braid shield provides effective attenuation (>30 dB) across the typical VFD emission spectrum from 10 kHz to 30 MHz. This covers all common IGBT carrier frequencies (2–16 kHz) and their harmonics. At frequencies above 30 MHz, shield attenuation decreases due to the braid’s optical coverage limitations, but VFD emissions above 30 MHz are typically negligible in magnitude and rarely cause operational problems in crane control systems.
Can I use the 2TC Light-SB for non-VFD applications where EMI immunity is still needed?
Absolutely. The shielded cable is also used in crane installations near high-power radio transmitters (port communication towers), in terminals with dense wireless infrastructure (5G base stations, Wi-Fi mesh networks), and in applications adjacent to high-voltage switchgear that generates switching transients. Any application requiring electromagnetic cleanliness benefits from the shield, regardless of whether VFDs are present.
What is the maximum recommended cable length for VFD output?
The cable length between VFD and motor should not exceed the VFD manufacturer’s specified maximum cable length (typically 100–300 metres depending on VFD rating and carrier frequency). Longer cable runs increase the cable’s parasitic capacitance, which can cause excessive charging current spikes at each IGBT switching event. For cable runs exceeding 100 metres, verify with the VFD manufacturer and consider adding an output reactor or dV/dt filter at the VFD output terminals. The 2TC Light-SB’s EP rubber insulation has lower parasitic capacitance than PVC, allowing somewhat longer cable runs than PVC-insulated alternatives.
References & Standards
- JIS C 3327, 600 V EP Rubber Insulated Polychloroprene Sheathed Cabtyre Cables (2PNCT, 2PNCT-SB) — Japanese Industrial Standard.
- JIS C 3005, Test methods for rubber and plastics insulated wires and cables.
- IEC 60228, Conductors of insulated cables — Classification and construction requirements.
- IEC 61800-3, Adjustable speed electrical power drive systems — Part 3: EMC requirements and specific test methods.
- IEC 61000-4-4, Electromagnetic compatibility (EMC) — Part 4-4: Testing and measurement techniques — Electrical fast transient/burst immunity test.
- IEC 62153-4-3, Metallic communication cable test methods — Part 4-3: Electromagnetic compatibility — Surface transfer impedance — Triaxial method.
- DuPont™ Kevlar® Technical Guide, Properties and Applications of Kevlar® Aramid Fibre.
- IEC 60811-1-1, Insulating and sheathing materials of electric and optical cables — Common test methods — General application.
- IEC 60364-5-54, Low-voltage electrical installations — Part 5-54: Selection and erection of electrical equipment — Earthing arrangements and protective conductors.
- FEM 1.001, Rules for the Design of Hoisting Appliances — Classification and loading on structures and mechanisms.
- ISO 9001:2015, Quality management systems — Requirements.
