1. Why the “OF” Designation Matters: The Salt-Fog Upgrade That Transforms MV Reeling Cable Service Life

In the Nexans RHEYFIRM® product nomenclature, the “OF” suffix (Öl- und Flammwidrig — oil- and flame-resistant) denotes a fundamental upgrade to the outer sheath compound that extends far beyond simple hydrocarbon resistance. The OF variant of the RHEYFIRM®(RTS) (N)TSCGEWTOEUS transforms a cable that already occupies the premium performance tier — RTS ultra-fine conductors, RHEYCLEAN® EPDM insulation, 5GM5 marine-grade polychloroprene sheath, six-core medium-voltage design with semi-conductive screens — into a cable purpose-engineered for the most chemically hostile operating environments that industrial reeling systems encounter: harbour terminals in ISO 9223 corrosivity category C5-M (marine), petrochemical port facilities with combined salt fog and hydrocarbon vapour exposure, and tropical coastal terminals where sustained humidity exceeding 90% RH compounds the corrosive effects of airborne chloride ions.

The engineering significance of the OF upgrade can be quantified through a single metric: salt fog endurance per ISO 9227 increases from 800–1,200 hours (standard RHEYFIRM RTS) to 1,000–1,500 hours (OF variant) — a 25–40% improvement that translates directly into extended harbour service life. More importantly, the OF sheath’s enhanced oil resistance reduces the surface energy of the sheath exterior, which reduces the adhesion of salt crystals to the cable surface during service. This secondary mechanism — reduced salt accumulation — is not captured by ISO 9227 testing (which applies continuous salt spray regardless of surface adhesion characteristics) but has measurable impact on real-world service life in ports where intermittent rain washes salt deposits from low-adhesion surfaces but not from standard polychloroprene surfaces where salt crystals embed in the polymer micro-texture.

The practical consequence for harbour engineers is significant. In a C5-M port environment, the standard RHEYFIRM®(RTS) (N)TSCGEWTOEUS delivers 8–12 years of service life. The OF variant extends this to 10–15 years — an additional 2–3 years per installation cycle. For an STS gantry crane with two medium-voltage reeling cables (typically 3×95+3×50/3 at 6/10 kV or 8.7/15 kV), each cable replacement requires 4–7 days of crane downtime. Over a 25-year crane service life, the OF variant eliminates one complete replacement cycle compared to the standard variant, saving US$200,000–400,000 per crane in combined cable material, installation labour, and revenue-loss costs.

2. Layer-by-Layer Engineering: Deconstructing the RHEYFIRM®(RTS) (N)TSCGEWTOEUS OF

The RHEYFIRM®(RTS) (N)TSCGEWTOEUS OF is a six-core medium-voltage reeling cable comprising three phase cores and three protective earth cores arranged in the interstices of the phase-core lay-up. The cable is manufactured to DIN VDE 0250 part 813 (medium-voltage reeling cables) with additional compliance to DIN VDE 0295 (conductor standards), DIN VDE 0298 (current-carrying capacity), DIN VDE 0472 (testing), and prEN 50363 (insulation and sheathing compounds). The voltage range spans 3.6/6 kV through 18/30 kV, with the 6/10 kV and 8.7/15 kV variants being most commonly specified for STS crane and ship unloader applications.

The cable’s construction, from innermost to outermost layer, comprises seven distinct engineering layers, each contributing to the cable’s combined mechanical, electrical, and anti-corrosion performance. The following sections examine each layer in detail, with specific attention to how the OF variant’s construction differs from the standard RHEYFIRM(RTS) and how each layer contributes to overall salt fog resistance.

3. RTS Ultra-Fine Conductor Technology: Corrosion-Fatigue Resistance at the Molecular Level

The “RTS” designation (Rheyfirm Torsion Spezial) represents a conductor stranding technology that exceeds IEC 60228 Class 5 requirements. Where standard Class 5 conductors use individual strand diameters of 0.15–0.21 mm, RTS conductors employ ultra-fine strands with diameters of 0.10–0.12 mm. This seemingly minor dimensional change — a reduction of approximately 30–50% in individual strand diameter — produces three engineering consequences that are profoundly significant for harbour cable durability.

Increased Strand Count and Stress Distribution

For a given conductor cross-section (e.g., 95 mm²), reducing strand diameter from 0.21 mm to 0.10 mm increases the number of individual strands by approximately 4.4× (from roughly 760 strands to approximately 3,350 strands). During bending, the tensile stress on the outermost strands is inversely proportional to the bend radius — but the total bending force is distributed across 4.4× more strands, reducing the stress per strand by approximately 75%. This stress reduction extends the cable’s fatigue life (bending cycles to conductor fracture) by approximately 3–5× compared to Class 5 stranding — the primary reason RTS cables achieve 120,000+ flex cycles versus 40,000–60,000 for Class 5.

Tin Coating Integrity Under Cyclic Bending

The critical salt-fog-relevant consequence of ultra-fine stranding is its effect on the protective tin coating. During cyclic bending, individual copper strands slide against each other (inter-strand friction). In Class 5 stranding with 0.21 mm diameter strands, the contact pressure between adjacent strands is sufficient to abrade the tin coating at contact points within 10,000–20,000 flex cycles, exposing bare copper to any chloride ions that have permeated through the insulation. In RTS stranding with 0.10 mm diameter strands, the inter-strand contact pressure is reduced by approximately 60% (because each strand carries less load), and the tin coating survives 40,000–60,000 flex cycles before significant abrasion occurs. This 3–4× extension of tin coating integrity directly delays the onset of chloride-induced copper pitting corrosion — the dominant conductor degradation mechanism in harbour cables.

FeiChun FC-TCB™ Enhancement: Beyond Standard Tinning

FeiChun’s FC-RHEYFIRM-RTS-OF equivalent employs FC-TCB™ (Tin-Copper-Barrier) conductor treatment on RTS-grade ultra-fine stranding. The FC-TCB process applies hot-tin-dipping with a minimum coating thickness of 2.5 μm (versus 1.0–1.5 μm for standard tinned conductors) and develops a controlled Cu₆Sn₅ intermetallic layer at the copper-tin interface. This intermetallic layer provides an additional diffusion barrier: even if the outer tin layer is partially abraded during flex cycling, the Cu₆Sn₅ intermetallic resists chloride penetration at a rate approximately 10× lower than pure tin, effectively providing a “second line of defence” at the conductor level — complementing the cable’s outer defence-in-depth architecture.

4. RHEYCLEAN® EPDM Insulation and Semi-Conductive Screens: The Chloride Barrier Within

The insulation system of the RHEYFIRM®(RTS) (N)TSCGEWTOEUS OF comprises three co-extruded layers: inner semi-conductive screen, RHEYCLEAN® EPDM insulation, and outer semi-conductive screen. This triple-extrusion construction, borrowed from medium-voltage utility cable technology (IEC 60502-2), provides both the electrical field grading necessary for medium-voltage operation and — in the context of harbour service — a multi-layer barrier against chloride ion penetration.

RHEYCLEAN® EPDM: Peroxide-Cured with Enhanced Cross-Link Density

The RHEYCLEAN® designation indicates an EPDM (ethylene propylene diene monomer) rubber compound that is peroxide-cured rather than sulfur-cured. This distinction is critical for salt fog resistance. Sulfur-cured EPR compounds contain residual sulfur compounds that can react with copper conductor surfaces at elevated temperatures (above 60°C), forming copper sulfide (Cu₂S) — a semiconducting compound that degrades insulation resistance. Peroxide-cured EPDM eliminates this failure mechanism entirely, hence the “CLEAN” designation (clean of sulfur contamination). For harbour service, the peroxide cure system provides an additional benefit: the carbon-carbon cross-links formed during peroxide curing are approximately 20% more resistant to hydrolytic degradation than carbon-sulfur cross-links, meaning the insulation maintains its mechanical and dielectric properties for longer periods under sustained high-humidity conditions typical of port environments.

The cross-link density of RHEYCLEAN® EPDM is approximately 15–20% higher than standard EPR compounds. Higher cross-link density reduces the free volume within the polymer matrix — the molecular-scale voids through which chloride ions diffuse. The resulting chloride diffusion coefficient of RHEYCLEAN® EPDM is approximately 5×10⁻¹³ cm²/s, compared to 2×10⁻¹² cm²/s for standard sulfur-cured EPR — a 4× reduction that, following Fick’s second law, roughly doubles the time before chloride ions at meaningful concentration reach the conductor surface through the insulation layer.

RHEYSTRIP® Semi-Conductive Screens: Easy Stripping and Chloride Barrier Function

The inner and outer semi-conductive screens (RHEYSTRIP® designation) are EVA (ethylene vinyl acetate)-based compounds formulated for two critical properties. Electrically, they provide smooth field grading between the metallic conductor and the EPDM insulation, eliminating partial discharge inception at the conductor-insulation interface (critical for medium-voltage reliability). Mechanically, they are formulated for easy cold stripping — the “STRIP” designation indicates that the semi-conductive layer peels cleanly from the insulation at temperatures down to −10°C, simplifying field termination on port crane installations where cable jointing may occur in cold conditions.

In the context of salt fog resistance, the semi-conductive screens provide an often-overlooked benefit: each screen represents an additional polymer layer with its own chloride diffusion coefficient, adding to the total diffusion path length between the cable exterior and the conductor. The two semi-conductive layers together contribute approximately 1.0–1.5 mm of additional polymer barrier, extending the chloride transit time by approximately 15–25% beyond what the insulation alone would provide.

5. The 5GM5 OFE Sandwich Sheath: Chloride Diffusion Modelling and Salt Fog Performance

The defining engineering feature of the RHEYFIRM®(RTS) (N)TSCGEWTOEUS OF — and the element that distinguishes it from all other cable families in this comparative analysis — is the 5GM5 OFE sandwich sheath construction. Understanding what “sandwich” means in this context, and why it transforms salt fog performance, requires examining the sheath at the compound-formulation level.

Standard 5GM5 vs. 5GM5 OFE: Compound Chemistry Differences

Standard 5GM5 polychloroprene (used on the base RHEYFIRM RTS) is a W-type chloroprene rubber compound formulated with magnesium oxide and zinc oxide acid acceptors, carbon black (N550 or N660 at 30–50 phr) for UV protection and mechanical reinforcement, paraffinic wax anti-ozonant systems, and phenolic antioxidants. This formulation delivers excellent mechanical properties (tensile strength ≥ 10 MPa, elongation at break ≥ 300% per ISO 37), good UV/ozone resistance, and moderate oil resistance.

The 5GM5 OFE compound modifies this formulation in three specific ways. First, it incorporates chlorinated paraffin plasticisers (replacing standard paraffinic plasticisers) that provide oil resistance — the chlorinated paraffin molecules are structurally similar to the polychloroprene polymer backbone, so they do not migrate or leach when the sheath contacts hydrocarbon oils, maintaining mechanical properties after prolonged oil exposure (less than 15% volume change after 168 hours immersion in IEC 60811 Test Oil A). Second, it increases the anti-ozone wax loading from approximately 2–3 phr (standard) to 4–6 phr (OFE), creating a thicker surface wax bloom that acts as a sacrificial barrier against both ozone attack and salt crystal adhesion. Third, and most significantly for salt fog performance, it employs a dual-layer extrusion (the “sandwich”) where the inner layer of the outer sheath is standard 5GM5 (optimised for flexibility and abrasion resistance) and the outer layer is 5GM5 OFE (optimised for chemical resistance and reduced surface energy).

Why Sandwich Construction Outperforms Monolithic OFE

A monolithic OFE sheath (single-layer, uniform OFE compound throughout) would provide maximum chemical resistance but at the cost of reduced flexibility — the chlorinated paraffin plasticisers that provide oil resistance also increase compound stiffness, raising the minimum bend radius and reducing flex-cycle endurance. The sandwich construction resolves this trade-off: the inner layer maintains the flexibility of standard 5GM5 (ensuring flex-cycle performance is not degraded), while the outer layer provides the chemical resistance and reduced surface energy of OFE (maximising salt fog and oil resistance). The interface between the two layers is co-vulcanised during extrusion, creating a chemical bond that prevents delamination even after millions of flex cycles.

6. Comparative Analysis: RHEYFIRM®(RTS) OF vs. RHEYFIRM®(SI) NTMCGCWOEUS

The RHEYFIRM®(SI) NTMCGCWOEUS is Nexans’ silicone-insulated medium-voltage reeling cable — a cable designed primarily for extreme temperature applications (hot-metal handling, steel terminal service, mining in volcanic or geothermal environments). Comparing it against the RHEYFIRM®(RTS) OF reveals fundamental differences in design philosophy that inform the correct cable selection for harbour applications.

Insulation Chemistry: Silicone (VMQ) vs. EPDM

Silicone rubber (polydimethylsiloxane / VMQ) provides extraordinary temperature performance: continuous operation from −60°C to +180°C, with short-term tolerance to +250°C. This thermal capability is the SI variant’s primary advantage and the reason it is specified for hot-cargo terminals. However, silicone’s molecular structure — a flexible Si-O-Si backbone with methyl side groups — gives it inherently lower mechanical strength compared to EPDM. The tensile strength of silicone insulation (typically 5–8 MPa) is approximately half that of RHEYCLEAN® EPDM (10–15 MPa), and its tear resistance (20–30 kN/m) is approximately one-third that of EPDM (50+ kN/m). In harbour environments where the cable surface is subject to abrasion from drum contact, impact from container handling operations, and point loading from cable guide rollers, this mechanical strength deficit translates to a higher risk of insulation damage — and any insulation damage immediately creates a fast pathway for chloride ion penetration to the conductor.

Salt Fog Performance: Intrinsic vs. Real-World

Silicone rubber has excellent intrinsic hydrophobicity — its low surface energy (approximately 22–25 mN/m) repels water and resists the formation of continuous electrolyte films that drive chloride-mediated corrosion. In pristine-surface ISO 9227 testing, the RHEYFIRM SI achieves 600–1,000 hours — respectable but lower than the RHEYFIRM RTS OF’s 1,000–1,500 hours. The paradox — silicone has lower surface energy than OFE polychloroprene but worse salt fog performance — is explained by the difference between intrinsic chemistry and mechanical durability. During ISO 9227 testing (pristine cable, no mechanical stress), silicone’s hydrophobicity is partially effective. During real-world port service (cable subject to continuous flex cycling, drum abrasion, and point loading), the silicone surface is micro-damaged, and its low tear resistance means these micro-damages propagate faster than equivalent damage in EPDM or OFE polychloroprene, creating chloride ingress points that overwhelm the intrinsic hydrophobic advantage.

7. Comparative Analysis: RHEYFIRM®(RTS) OF vs. Standard RHEYFIRM®(RTS) (N)TSCGEWTOEUS

The comparison between the OF and standard variants of the RHEYFIRM®(RTS) (N)TSCGEWTOEUS isolates the precise engineering value of the OF sheath upgrade, because every other cable layer — conductor, insulation, semi-conductive screens, inner sheath, anti-torsion braid — is identical between the two variants.

Sheath Compound: 5GM5 vs. 5GM5 OFE

The standard RHEYFIRM RTS uses a monolithic 5GM5 polychloroprene sheath. The OF variant uses the 5GM5/5GM5 OFE sandwich construction described in Section 5. The measurable consequences of this difference are summarised in three performance domains. Salt fog endurance (ISO 9227): standard achieves 800–1,200 hours; OF achieves 1,000–1,500 hours — a minimum 25% improvement attributable to the OFE outer layer’s reduced chloride diffusion coefficient and lower salt crystal adhesion. Oil resistance (IEC 60811, Test Oil A, 168 hours): standard shows 20–30% volume swell; OF shows less than 15% — directly relevant for harbour cables that contact hydraulic fluid from crane machinery. Flex-cycle endurance: effectively identical (120,000+ cycles) because the inner sheath layer (which determines flex performance) is standard 5GM5 in both variants.

Cost-Benefit Analysis: The OF Premium Justified

The OF variant typically commands a 10–18% price premium over the standard RHEYFIRM RTS. For a typical STS crane MV reeling cable installation (2 cables × 350 m × 3×95+3×50/3 at 6/10 kV), this premium represents approximately US$15,000–25,000 per crane. Against this investment, the OF variant delivers 2–3 additional years of service life (10–15 years vs. 8–12 years), potentially eliminating one complete cable replacement cycle over the crane’s 25-year service life. Each avoided replacement cycle saves US$200,000–400,000 (cable + installation + downtime). The return on investment for the OF upgrade is therefore approximately 8:1 to 27:1 — one of the highest ROI decisions available to port electrical engineers.

8. Comparative Analysis: RHEYFIRM®(RTS) OF vs. RHEYCORD®-OFE SR and BUFLEX® SEM OFE

Two other cable families in the Nexans portfolio carry the “OFE” designation and are sometimes considered as alternatives to the RHEYFIRM RTS OF: the RHEYCORD®-OFE SR (low-voltage OFE spreader cable) and the BUFLEX® SEM OFE (premium energy-chain OFE cable). Comparing these cables against the RHEYFIRM RTS OF reveals critical differences in voltage class, mechanical architecture, and application suitability that prevent them from being interchangeable.

RHEYCORD®-OFE SR: Low-Voltage Spreader-Rated OFE Cable

The RHEYCORD-OFE SR is a 0.6/1 kV low-voltage reeling cable rated for spreader bar duty (tensile capacity 3,000–5,000 N). It shares the OFE sheath chemistry with the RHEYFIRM RTS OF and achieves comparable salt fog endurance (1,000–1,500 hours). However, it operates at a fundamentally different voltage class — the RHEYCORD-OFE SR has no semi-conductive screens, no medium-voltage insulation wall thickness, and no medium-voltage field-grading architecture. It cannot replace a RHEYFIRM RTS OF in any MV application. Conversely, using a RHEYFIRM RTS OF where a RHEYCORD-OFE SR would suffice (i.e., in a 0.6/1 kV application) is technically feasible but economically wasteful — the MV cable’s larger diameter, higher weight, and greater cost per metre provide no benefit at low voltage.

BUFLEX® SEM OFE: Premium Energy-Chain OFE Cable

The BUFLEX SEM OFE is a low-voltage (0.6/1 kV) energy-chain cable with BU (bundled ultra-fine) conductors, enhanced EPR insulation, 5GM5 OFE sheath, and aramid-reinforced anti-torsion braid. It achieves excellent salt fog performance (1,000–1,500 hours) and high flex-cycle endurance (80,000–100,000 cycles). However, the BUFLEX SEM OFE is designed for energy-chain (drag-chain) service, not motorised drum reeling — its conductor stranding is optimised for small-radius bending in energy chains rather than the combined torsion, tension, and multi-plane deflection that characterise motorised drum reeling. Using a BUFLEX SEM OFE on a motorised MV reel would result in premature torsion failure because the BU stranding pattern distributes torsional stress differently than the RTS stranding pattern optimised for drum service.

9. Comprehensive Performance Matrix: All Five Cable Families Side-by-Side

The following matrix consolidates the comparative analysis from Sections 6–8 into a single reference table, enabling harbour engineers to evaluate all five cable families across 18 critical performance parameters simultaneously. This matrix is designed for direct use in cable selection decisions and can be incorporated into procurement RFQ documentation.

10. ISO 9227 Salt Spray Testing: Methodology, Limitations, and Field Correlation

All salt fog performance figures cited in this article refer to testing per ISO 9227 Neutral Salt Spray (NSS) — the international standard that exposes cable samples to continuous 5% NaCl solution spray at 35°C in a controlled fog chamber. While ISO 9227 provides the only internationally standardised and reproducible method for comparing salt fog resistance between cable types, harbour engineers must understand its limitations to correctly interpret the test hours and correlate them to expected field service life.

What ISO 9227 Tests (and What It Doesn’t)

ISO 9227 NSS applies a continuous, uniform salt spray to pristine cable samples in a temperature-controlled chamber. It effectively measures the intrinsic chemical resistance of the cable’s outer sheath to chloride ion penetration under idealised conditions. It does not replicate: UV radiation (which creates surface micro-cracks that accelerate chloride penetration), mechanical stress (which opens internal pathways through the polymer matrix), temperature cycling (which causes differential expansion and contraction that propagates micro-cracks), or humidity cycling (which drives alternating wetting and drying that concentrates salt deposits in micro-crevices). These real-world stress factors — acting simultaneously and synergistically — mean that actual harbour service life cannot be predicted by simple linear extrapolation from ISO 9227 hours.

Field Correlation: ISO 9227 Hours to Port Service Years

FeiChun’s field experience database, compiled from installation records across 47 container terminals in Asia-Pacific, Middle East, Africa, and Southern Europe, provides empirical correlation between ISO 9227 test hours and observed port service life. The correlation is non-linear: the first 500 hours of ISO 9227 endurance correlates to approximately 3–4 years of C5-M port service (because the real-world synergistic degradation factors dominate early life), while each additional 100 hours beyond 500 correlates to approximately 1–1.5 additional years (because the cable’s construction has already demonstrated resistance to the primary degradation mechanisms). This non-linear correlation explains why the RHEYFIRM RTS OF’s advantage over the standard variant (200–300 additional ISO 9227 hours) translates to 2–3 additional years of service life rather than the 0.5–1 year that linear extrapolation would predict.

11. FeiChun FC-RHEYFIRM-RTS-OF: Enhanced Anti-Salt-Fog Equivalent Engineering

FeiChun’s FC-RHEYFIRM-RTS-OF is a direct technical equivalent to the Nexans RHEYFIRM®(RTS) (N)TSCGEWTOEUS OF, manufactured to DIN VDE 0250 part 813 with identical six-core medium-voltage construction, RTS-grade ultra-fine stranding, EPDM insulation with semi-conductive screens, aramid-reinforced anti-torsion braid, and 5GM5 OFE outer sheath. However, the FC-RHEYFIRM-RTS-OF incorporates FeiChun’s FC-PORT™ defence-in-depth anti-salt-fog enhancements at each cable layer, producing measurably superior salt fog performance compared to the Nexans original in three specific areas.

Enhancement 1: FC-TCB™ Conductor Treatment

As described in Section 3, FeiChun’s FC-TCB™ (Tin-Copper-Barrier) treatment increases tin coating thickness to ≥ 2.5 μm (versus 1.0–1.5 μm standard) and develops a Cu₆Sn₅ intermetallic barrier layer. The practical effect for MV harbour cables is extended conductor integrity: DC resistance increase due to chloride-induced pitting corrosion remains below 3% over 15 years of C5-M service, compared to 5–8% for standard tinned conductors — ensuring that the cable maintains its rated current-carrying capacity throughout its service life without the need for derating as conductors degrade.

Enhancement 2: Nano-Clay-Enhanced EPDM Insulation

FeiChun’s EPDM insulation compound incorporates nano-clay fillers (organically modified montmorillonite at 3–5 phr) that create tortuous diffusion paths for chloride ions within the insulation matrix. The nano-clay platelets — measuring approximately 1 nm thick and 100–200 nm in lateral dimension — are exfoliated and uniformly dispersed during compound mixing, creating a “labyrinth” structure that forces chloride ions to travel approximately 3× the straight-line distance through the insulation. The resulting effective chloride diffusion coefficient is approximately 1.5×10⁻¹³ cm²/s — approximately 3× lower than standard RHEYCLEAN® EPDM (5×10⁻¹³ cm²/s) — extending the insulation-layer chloride transit time from approximately 15–25 years to approximately 45–75 years. While the outer sheath will require replacement before this timescale is reached, the nano-clay-enhanced insulation provides an order-of-magnitude safety margin that ensures the conductor remains protected even if the outer sheath is significantly compromised by mechanical damage or accelerated UV degradation.

Enhancement 3: FC-ASB™ Aramid Braid and Enhanced 5GM5+ OFE Sheath

The FC-RHEYFIRM-RTS-OF uses FeiChun’s FC-ASB™ (Aramid Strength Braid) anti-torsion system — a non-metallic braid that provides equivalent tensile capacity to standard aramid/polyester braid but with complete corrosion immunity. The outer sheath employs FeiChun’s 5GM5+ OFE formulation with an additional 1–2 phr of benzotriazole-based UV absorber (compared to standard 5GM5 OFE), extending the sheath’s UV resistance from 2,000 hours (ISO 4892-2 accelerated weathering) to 2,500+ hours — an important enhancement for tropical ports where cumulative UV exposure is the sheath’s primary surface degradation mechanism.

12. Specification, Procurement, and Application Decision Framework

When to Specify RHEYFIRM®(RTS) (N)TSCGEWTOEUS OF (or FeiChun FC-RHEYFIRM-RTS-OF)

The RHEYFIRM RTS OF / FC-RHEYFIRM-RTS-OF is the correct specification when all of the following conditions apply: the application requires medium-voltage power delivery (3.6/6 kV or above); the cable operates on a motorised reeling drum (not energy chain or festoon); the installation is in a harbour or coastal environment with ISO 9223 corrosivity category C4 or C5-M; the cable is exposed to salt fog, UV radiation, or marine atmosphere for any portion of its reeling cycle; maximum salt fog resistance and maximum service life are prioritised over initial cable cost; and the reeling speed exceeds 120 m/min (which eliminates lower-tier alternatives). If any of these conditions is not met, a less specialised cable family may be more appropriate — refer to the decision framework below.

Application Decision Framework for Port MV Reeling Cables

Work through these decision points sequentially to identify the correct cable specification for your installation.

Specification Template for Procurement (RFQ Language)

The following specification language can be used directly in procurement RFQ documents for MV port reeling cables: “Medium-voltage reeling cable for harbour crane service. Type: RHEYFIRM®(RTS) (N)TSCGEWTOEUS OF or approved equivalent (e.g., FeiChun FC-RHEYFIRM-RTS-OF). Rated voltage: [specify, e.g., 6/10 kV or 8.7/15 kV]. Core configuration: 3×[specify, e.g., 95]+3×[specify, e.g., 50]/3. Conductor: RTS ultra-fine stranded tinned copper, better than IEC 60228 Class 5. Insulation: Peroxide-cured EPDM with inner and outer semi-conductive screens. Anti-torsion: High-tensile synthetic (aramid or aramid/polyester) braid. Outer sheath: 5GM5 OFE polychloroprene, sandwich construction, oil-resistant per EN 60811-2-1 (Test Oil A, 168 h, < 15% volume change). Temperature range: −40°C to +90°C continuous. Maximum reeling speed: ≥ 200 m/min. Salt fog endurance: ≥ 1,000 hours per ISO 9227 NSS. Corrosivity environment: C5-M per ISO 9223. Flex-cycle endurance: ≥ 100,000 cycles at 10× OD per DIN 53375. Flame retardancy: IEC 60332-1. Standards compliance: DIN VDE 0250-813. Certification: VDE mark or equivalent. Test reports required with delivery: ISO 9227 salt spray, IEC 60068-2-52 Severity 2, partial discharge test, routine electrical test per VDE 0250-813.”