Introduction: Maximum Voltage Through Minimum Space

BUFLEX®-SC is an extra-flexible, single-core, polyurethane (PUR) medium voltage cable engineered by Anhui Feichun Special Cable Co., Ltd. for the applications that multi-core reeling cables cannot serve—applications where a single, massively powerful conductor must be routed through impossibly tight spaces, terminated with absolute precision, and survive mechanical abuse that would destroy conventional rubber cables in weeks.

Consider the inside of a modern compact switchgear cabinet rated at 24 kV. The space available for cable routing is measured in centimetres, not metres. Three separate single-core cables—one per phase—must be bent through 90° and 180° turns inside a metal enclosure barely wider than the cables themselves. Each cable must be terminated with surgical precision: the outer jacket stripped, the copper screen exposed and earthed, the outer semi-conductive layer peeled away cleanly, and the EPR insulation surface left pristine and void-free for the stress cone or heat-shrink termination kit. A single scratch on the insulation surface during termination creates a field stress concentration that will initiate partial discharge. A single air void trapped between the semi-conductive layer and the insulation creates a corona channel that will burn through the cable in months. The termination is the single point of failure that determines whether the cable operates flawlessly for 25 years or catastrophically fails during the first thunderstorm.

This is the engineering reality that BUFLEX-SC is designed to solve. And it is the engineering reality where Feichun has introduced three innovations that do not exist in the Nexans original or any other European equivalent: FC-EZS™ Easy-Strip semi-conductive technology that guarantees void-free terminations every time, FC-ASB™ aramid-reinforced PUR outer sheath that provides ballistic-grade mechanical protection in a slim-profile jacket, and Tongling Cu-CATH-1 premium copper conductors that deliver the lowest electrical resistance and highest oxidation immunity available in any medium voltage single-core cable on the global market.

These three innovations are not incremental improvements. They are fundamental material science upgrades that address the three primary failure modes observed in medium voltage single-core cables worldwide: termination failure from poor semi-conductive stripping, jacket breach from mechanical abuse, and conductor overheating from impure copper resistance. Feichun’s BUFLEX-SC eliminates all three failure modes simultaneously—delivering a cable that is not merely equivalent to the European original, but measurably superior in the three dimensions that matter most for operational reliability.

Technical Anatomy: BUFLEX®-SC Full Specification Breakdown

A single-core medium voltage cable has a deceptively simple cross-section: one conductor, one insulation system, one screen, one jacket. But within this apparently simple geometry, the electrical field management challenge is immense. Unlike multi-core cables where the three phases share a common electromagnetic environment, a single-core cable’s electromagnetic field is radially symmetric and entirely self-contained. The semi-conductive layers, screening, and insulation must manage this concentrated field with absolute precision, because any defect—no matter how microscopic—exists in direct line between the full phase voltage and earth.

FC-EZS™ Easy-Strip: The Innovation That Eliminates Termination Failures

The Termination Crisis: Why 60% of MV Single-Core Failures Start at the Cable End

When a high-voltage electrician terminates a medium voltage single-core cable, the procedure follows a precise, unforgiving sequence. First, the outer PUR jacket is removed for the specified length. Then the copper screen is cut back and earthed. Then the outer semi-conductive layer must be removed cleanly from the EPR insulation surface to expose the insulation for the stress cone or termination kit. This final step—stripping the semi-conductive layer—is where the majority of catastrophic failures originate.

The outer semi-conductive layer is a thin, black, rubbery compound that is extruded directly onto the EPR insulation surface. In conventional cables, this layer is bonded to the insulation with significant adhesion force—typically 2.5–4.0 N/mm of strip force. Removing it requires the electrician to score the layer circumferentially with a cable knife, then peel it away from the insulation surface using controlled pulling force. This is where the failures occur, and they come in three devastating forms.

Failure Mode 1: Insulation Scratching. The semi-conductive layer is so tightly bonded to the EPR insulation that the electrician must apply substantial knife pressure to score through it. The knife blade, guided by hand in a confined switchgear cabinet where visibility is poor and working angles are awkward, cuts through the semi-conductive layer and scratches the underlying EPR insulation. The scratch creates a field stress concentration—a point where the electric field intensity is dramatically higher than the surrounding insulation. At 18/30 kV, this concentrated field initiates partial discharge at the scratch. Over weeks or months, the discharge burns a conductive channel through the insulation. The cable fails explosively.

Failure Mode 2: Residual Semi-Conductive Material. The semi-conductive layer does not peel cleanly. Fragments of semi-conductive material remain adhered to the insulation surface, creating conductive islands on what should be a uniformly insulating surface. These islands create localised field distortions that concentrate electric stress at their edges. Corona discharge initiates at these edges, progressively burning through the surrounding insulation.

Failure Mode 3: Trapped Air Voids. As the semi-conductive layer is pulled away from the insulation, the separation does not occur uniformly. Some areas separate cleanly; others resist and then release suddenly, creating microscopic air pockets between the layers. If the termination kit (stress cone or heat-shrink) is applied before these voids are detected and eliminated, the voids are permanently sealed inside the termination. The high voltage ionizes the trapped air, creating corona discharge that burns through the termination components.

The FC-EZS™ Solution: Engineered Peel Force and Clean Separation

Feichun’s FC-EZS™ (Easy-Strip Semi-conductive) technology addresses all three failure modes through a fundamentally re-engineered semi-conductive compound. The key innovation is the precise control of the adhesion force between the outer semi-conductive layer and the EPR insulation surface—what cable engineers call the “peel force” or “strip force.”

Conventional semi-conductive compounds bond to EPR with peel forces of 2.5–4.0 N/mm—strong enough that aggressive knife pressure is required to initiate separation, creating the scratching and residual-material problems described above. At the other extreme, some budget manufacturers use very weakly bonded semi-conductive layers (below 0.5 N/mm) that are easy to strip but risk delaminating from the insulation during the cable’s operational life, creating internal voids that cause corona discharge in service.

FC-EZS™ is engineered to occupy the precise “sweet spot” of peel force: 0.8–1.2 N/mm. This range is firm enough to maintain perfect bonding throughout 25+ years of continuous operation, dynamic flexing, thermal cycling, and mechanical vibration—but gentle enough that a trained electrician can score and strip the layer with minimal knife pressure, producing a clean, smooth, void-free insulation surface ready for termination. The layer peels in controlled, uniform strips without fragmenting, tearing, or leaving residual conductive material on the insulation surface.

The Material Science Behind FC-EZS™

Achieving precise peel-force control requires fundamental compound chemistry innovation, not simply adjusting one ingredient. Conventional semi-conductive compounds use carbon black as the conductive filler dispersed in an EPR or EPDM rubber matrix. The compound is vulcanized (cross-linked) simultaneously with the EPR insulation during the CCV triple-extrusion process. The problem is that during vulcanization, the chemical cross-linking agents in the semi-conductive compound react with the surface of the EPR insulation, creating strong covalent bonds at the interface. These bonds are what make the layer so difficult to strip.

FC-EZS™ uses a proprietary controlled-interface formulation that introduces a precisely calibrated release agent into the semi-conductive compound’s surface chemistry. This release agent migrates preferentially to the semi-con/insulation interface during vulcanization, forming a molecular monolayer that limits the number of covalent bonds formed between the two surfaces. The release agent does not create a “slippery” or “weak” interface—it creates a controlled-adhesion interface where the bond strength is precisely tuned to the 0.8–1.2 N/mm target range.

Critically, the release agent is thermally stable up to 130°C and chemically inert to the EPR insulation compound. It does not migrate further into the insulation over time (which would create a weak zone inside the insulation), and it does not degrade under continuous electrical stress. Twenty-five-year accelerated thermal aging tests (IEC 60811 protocols at 135°C equivalent aging) confirm that FC-EZS™ peel force remains within the 0.8–1.2 N/mm specification throughout the cable’s entire design life. The bond is permanent—it simply requires less force to break when deliberately separated during termination.

Aramid-Reinforced PUR: Bulletproof Protection for Single-Core Exposure

Why Single-Core Cables Face Greater Mechanical Risk Than Multi-Core

A multi-core reeling cable operates as a single, unified structure—all three phases travel together, share the mechanical load, and are protected by a common outer jacket that distributes contact forces across a large surface area. A single-core cable has no such luxury. Each individual cable is exposed independently to the full mechanical environment. When three single-core BUFLEX-SC cables are routed through a switchgear cabinet, each cable contacts sharp metal edges, cable clamps, gland fittings, and adjacent cables independently. When used as a temporary MV jumper cable at a mine site, the single-core cable is dragged across rocky ground, coiled and uncoiled by hand, stepped on by workers, and potentially run over by vehicles.

This exposed operating environment makes the outer jacket of a single-core cable disproportionately more important than on a multi-core cable. A jacket breach on a single-core cable directly exposes the copper screen and semi-conductive layer to the environment. Moisture ingress through the breach attacks the insulation interface. In outdoor applications, UV radiation degrades the exposed semi-conductive material. The cable’s single conductor carries the entire phase current, so any insulation degradation affects the full power circuit—there is no redundancy.

FC-ASB™: Aramid Integration for Single-Core Survival

Feichun’s FC-ASB™ (Aramid Stress-relief Braid) technology integrates para-aramid fiber—the identical polymer used in military body armour—directly into the PUR outer sheath compound at the molecular level. The aramid fibers are surface-treated with a proprietary coupling agent that creates covalent bonds between the aramid surface and the PUR isocyanate polymer chains. This produces a true composite jacket where the PUR and aramid function as a single, unified material structure.

For BUFLEX-SC single-core applications, the aramid reinforcement provides three critical protection mechanisms. First, cut-through resistance: when the cable contacts a sharp metal edge inside a switchgear cabinet, the aramid fibers distribute the concentrated contact force across thousands of interconnected fiber strands, preventing the edge from cutting through the jacket. Standard PUR at 3 mm wall thickness can be cut through with 120–150 N of force applied through a 0.5 mm blade; aramid-reinforced PUR at the same thickness requires 220–280 N—nearly double the force-to-cut.

Second, tear propagation arrest: if a surface defect develops from abrasion or impact, the aramid fiber network physically prevents the defect from growing under cyclic mechanical loading. The crack tip energy is absorbed and distributed across the aramid network rather than concentrating at the leading edge of the tear. Third, impact resistance: the aramid-PUR composite absorbs sudden impact energy (dropped tools, vehicle contact, falling objects at construction sites) without cracking or fracturing—critical for temporary jumper cable applications in harsh industrial environments.

Tongling Premium Copper: Ultra-Low Resistance for Single-Core Current Density

Why Copper Purity Matters More in Single-Core Cables

In a multi-core cable, heat generated by conductor resistance is shared across three (or more) parallel conductors, and the cable’s larger thermal mass provides a heat-sinking buffer. In a single-core cable, the entire phase current flows through one conductor, and the heat generated by that single conductor’s resistance must be dissipated through the cable’s comparatively small cross-section. The thermal challenge is more concentrated, and the consequences of excessive resistance are more severe.

A 95 mm² single-core cable carrying 250 A at 12/20 kV generates approximately 1.25 W/m of I²R heat with standard commercial copper (resistivity at IEC 60228 maximum). The same conductor made from Tongling Cu-CATH-1 copper at 99.97%+ purity generates approximately 1.21 W/m—a 3.2% reduction that translates to approximately 2.5°C lower conductor temperature at thermal equilibrium in still air. This temperature difference may sound modest, but its impact on insulation life is significant: at the 80°C continuous rating, every 2.5°C reduction in operating temperature extends EPR insulation thermal life by approximately 15–20% (per Arrhenius relationship with 8–10°C halving interval).

For BUFLEX-SC applications in confined spaces (switchgear cabinets, enclosed cable trays, underground conduits) where heat dissipation is restricted, the Tongling copper advantage becomes even more pronounced. In derating calculations for grouped or enclosed cables, the lower baseline heat generation per meter means the cable can carry marginally higher current before reaching the thermal limit—or operate at the rated current with greater thermal safety margin. Either way, the premium copper delivers measurable engineering value that directly impacts cable longevity and operational safety.

Oxidation Immunity for Long-Term Single-Core Connections

Single-core MV cables are terminated individually at both ends. Each termination involves exposed copper surfaces at the conductor lug connection and the screen earthing point. These exposed copper surfaces are vulnerable to oxidation, particularly in outdoor, marine, or humid tropical environments. Copper oxide (Cu₂O and CuO) formation on termination surfaces increases contact resistance at the lug-conductor interface, creating localised hot spots that accelerate insulation aging near the termination—precisely where electrical field stress is already at its highest.

Tongling Cu-CATH-1 copper, with its superior crystal lattice uniformity and minimal grain boundary defects, exhibits measurably slower surface oxidation rates compared to standard commercial copper. Combined with Feichun’s hot-dip tinning process (which achieves uniform, defect-free tin coverage on the pure copper substrate), the conductor surfaces remain electrically pristine for decades. This is particularly important for mobile substation and mine jumper applications where cables are terminated and re-terminated multiple times over their service life—each re-termination exposes fresh copper surfaces that must resist oxidation until the next maintenance cycle.

The Single-Core PUR Advantage: Why BUFLEX-SC Defeats Rubber in Tight Spaces

Bending Radius: The Single Most Important Specification for Switchgear Routing

When routing a 1×95 mm² cable rated 12/20 kV inside a compact switchgear cabinet, the critical specification is minimum bending radius. A cable that can bend tighter can be routed through smaller cabinets, around tighter corners, and terminated in less space. This directly determines whether a given cable can physically fit inside a given switchgear design.

Standard neoprene-sheathed MV single-core cables typically require a minimum static bending radius of 8–10 × cable OD and a dynamic radius of 15 × OD. Feichun’s aramid-reinforced PUR BUFLEX-SC achieves 6 × OD static and 10 × OD dynamic—a 25–40% reduction in minimum bending radius compared to neoprene equivalents. For a 12/20 kV cable with 95 mm² conductor and typical OD of 32 mm, this means a minimum static bend radius of 192 mm (PUR) versus 256–320 mm (neoprene)—a difference that can determine whether three single-core cables physically fit inside a switchgear cabinet or not.

The PUR advantage in bending radius comes from two material properties: higher elongation at break (PUR stretches further before the outer bend surface cracks) and lower elastic modulus (PUR requires less force to achieve a given bend angle). The aramid reinforcement adds tear resistance at the outer bend surface without increasing stiffness, creating additional safety margin against bend-induced jacket cracking. The result: a cable that bends more tightly, more easily, and more safely than any rubber equivalent.

Reduced OD: More Cable in Less Space

PUR’s superior mechanical properties permit a thinner jacket (2.2–3.8 mm versus neoprene’s 3.5–5.5 mm at equivalent voltage ratings), reducing overall cable OD by 10–18%. For three single-core cables routed together in a trefoil configuration inside a cable tray or duct, the reduced OD means the trefoil formation is smaller, the cable tray can be narrower, and the duct cross-section can be reduced. In mobile substation and containerised substation applications where every cubic centimetre of internal space is designed to specific purpose, the smaller trefoil formation of PUR cables can be the difference between a functional layout and an impossible one.

Surface Toughness for Rough Handling

MV jumper cables at mine sites and rail installations are not treated gently. They are dragged across gravel, dropped on concrete, pulled through steel cable glands, clamped with hand tools, and stored coiled in metal baskets exposed to weather. Standard neoprene jackets develop surface gouges, abrasion marks, and stress whitening within months of this treatment. Feichun’s aramid-reinforced PUR absorbs this abuse without visible damage—the aramid fiber network distributes impact and abrasion forces across the jacket structure, preventing the localised damage that initiates jacket failure.

Triple-Extrusion CCV: Absolute Corona Control for Single-Core Geometry

Why Corona Control is More Critical in Single-Core Design

In a multi-core cable, the electromagnetic fields of the three phases partially cancel each other in the space between cores. In a single-core cable, the entire electromagnetic field of one phase is concentrated radially around a single conductor with no cancellation from adjacent phases. The electric field gradient across the insulation wall is steeper, the field stress at the conductor-insulation interface is higher, and any defect in the insulation system has the full phase voltage driving corona discharge directly through it.

This is why single-core MV cables are more vulnerable to corona discharge than multi-core cables at the same voltage rating, and why the manufacturing process must be even more precisely controlled. A micro-void that might remain benign in a multi-core cable’s shared-field environment can initiate fatal corona discharge in a single-core cable’s concentrated-field environment.

Feichun’s CCV Process: Zero Voids, Zero Exceptions

Feichun manufactures BUFLEX-SC using German-designed Catenary Continuous Vulcanization (CCV) lines where the inner semi-conductive layer (including the FC-EZS™ compound for the outer semi-con), EPR dielectric core, and outer semi-conductive layer are extruded simultaneously through a single multi-chamber die. All three layers bond at the molecular level while still molten. The result: zero air gaps between any layer interfaces. Corona discharge has no initiation point.

For BUFLEX-SC, Feichun applies an additional quality control step not used for multi-core cables: 100% full-length partial discharge mapping. Rather than testing a cable sample or batch representative, every single meter of every single BUFLEX-SC cable is scanned for partial discharge activity using inline PD sensors positioned at the CCV line exit. The cable passes through a high-voltage test zone at 1.5× rated voltage while PD sensors record discharge activity along the entire length. Any section showing PD above 3 pC (more stringent than the standard 5 pC limit) is flagged, removed, and scrapped. This 100% length-mapped PD testing is unique to Feichun’s single-core production and provides a level of quality assurance that exceeds any other manufacturer’s standard protocol.

Concentric Copper Screening: Earth-Fault Management in Single-Core Design

Why Screening Design Matters More in Single-Core Cables

In a multi-core cable with individual core screens, the three screens share a common outer sheath and earthing system. In a single-core cable, the screen is the sole barrier between the energized insulation surface and the outer jacket. If the screen fails or is insufficiently rated, the outer jacket becomes electrically stressed, potentially creating a shock hazard on the cable surface.

Feichun offers two screening options for BUFLEX-SC, selectable based on application requirements. Concentric copper wire braid (minimum 90% optical coverage) provides excellent flexibility for applications requiring tight bending radii and frequent handling—ideal for switchgear routing and mobile jumper cables. Copper tape spinning (100% metallic coverage) provides absolute electromagnetic shielding and maximum earth-fault current capacity—ideal for fixed installations in substations where EMI performance and fault-current rating are paramount.

Both screening options use tinned copper for corrosion protection. The screen cross-section is calculated per IEC 60949 to carry the rated earth-fault current for 1 second without exceeding the screen’s thermal limit—ensuring that in the event of an insulation breakdown, the fault current flows safely through the screen to earth rather than arcing through the jacket to nearby metalwork or personnel.

Real-World Applications: From Switchgear to Mine Shafts

Compact Switchgear and Ring Main Units (RMU)

Modern gas-insulated switchgear (GIS) and ring main units are designed with progressively smaller internal dimensions as manufacturers optimise material usage and installation footprint. The internal cable compartment—where MV cables are terminated—is often the tightest space in the entire unit. Three BUFLEX-SC cables must be routed through cable glands, bent 90° or more, and terminated onto busbar connections within a space of 200–400 mm depth. The 6× OD static bending radius of Feichun’s PUR construction makes this physically achievable. The FC-EZS™ Easy-Strip semi-conductive layer makes the termination process faster and safer in the confined space where knife control and visibility are limited. Switchgear manufacturers across China, Southeast Asia, and the Middle East have standardised on Feichun BUFLEX-SC for their internal cable routing requirements.

Mobile and Containerised Transformer Substations

Mobile substations—trailer-mounted or containerised transformer units deployed for emergency power restoration, temporary construction supply, or event power—use single-core MV cables to connect the incoming supply to the transformer primary windings. These cables are connected and disconnected repeatedly as the substation moves between deployment sites. The FC-EZS™ Easy-Strip technology is critically valuable here: faster, cleaner terminations at each deployment reduce setup time and eliminate the termination failures that can render a mobile substation inoperable at the moment it is needed most. The aramid-reinforced PUR jacket survives the transport vibration, loading/unloading impacts, and rough outdoor handling inherent to mobile substation operations.

Mine Site MV Jumper Cables

Underground and open-pit mining operations frequently require temporary MV power connections—jumper cables that bridge between permanent infrastructure and mobile equipment, temporary loads, or emergency bypass circuits. These jumper cables are handled roughly, stored outdoors, and terminated under time pressure by electricians working in challenging conditions. BUFLEX-SC’s aramid-reinforced PUR jacket survives the mechanical abuse of mine environments (rock abrasion, equipment contact, chemical exposure). The FC-EZS™ Easy-Strip layer enables field terminations that are fast and reliable even when performed underground with limited tools and poor lighting. The Tongling copper conductors deliver lower resistance and less heat generation in mine ventilation-restricted environments where cable temperature management is critical for safety.

Railway Electrification and Traction Power

Railway traction power substations and trackside power distribution systems use single-core MV cables for connections between transformers, switchgear, and trackside equipment. The cables must withstand vibration from passing trains, thermal cycling from ambient temperature variation, and electromagnetic interference from traction power systems. BUFLEX-SC’s concentric copper braid screen provides excellent EMI shielding in these electrically noisy environments. The reduced OD permits routing through existing cable ducts and conduits designed for older, thicker cables—avoiding expensive civil works for duct enlargement.

Renewable Energy: Wind and Solar Farm Collector Systems

Wind farm and solar farm collector cable systems use single-core MV cables to connect individual turbine transformers or inverter stations to the substation bus. Cable lengths of 500–2,000 meters are common. In these applications, the lower conductor resistance of Tongling copper translates directly into reduced electrical losses across the collector network—potentially representing hundreds of MWh of additional energy capture per year across a large installation. The aramid-reinforced PUR jacket provides UV resistance and mechanical toughness for cables exposed to harsh outdoor environments over 25+ year design lives.

Festoon and Reeling Systems

Single-core BUFLEX-SC cables can be deployed in festoon (catenary) systems and single-core reeling applications where individual phase routing is required—for example, on large overhead cranes where each phase feeds a separate drive motor or where phase segregation is required for electromagnetic compatibility. The anti-torsion braid prevents corkscrewing during festoon travel, while the aramid-reinforced PUR jacket resists the cyclic bending and abrasion of festoon carrier systems. Operating speeds up to 60 m/min (festoon) or 120 m/min (dedicated reeling) are supported.

Cost-Effective Alternative to European Premium Single-Core PUR Suppliers

The European Single-Core Premium

Nexans, Prysmian, TF Kable, and Lapp supply BUFLEX-SC equivalent cables at premium pricing reflecting European manufacturing costs and multi-tier distribution. Standard lead times exceed 16–24 weeks. For single-core cables where three separate cables are required per circuit (one per phase), the total cost per circuit is three times the per-cable price—amplifying the European supplier premium significantly. A three-phase circuit of 18/30 kV, 95 mm² single-core PUR cables totalling 300 meters per phase (900 meters total) can cost €90,000–€135,000 from European suppliers.

Feichun: Three Innovations Not Available from Europe

Feichun’s BUFLEX-SC is not merely a cost-equivalent alternative—it includes three proprietary innovations (FC-EZS™, FC-ASB™, Tongling premium copper) that European manufacturers do not offer. European BUFLEX-SC cables use conventional semi-conductive compounds that are difficult to strip, standard PUR without aramid reinforcement, and standard commercial copper. Feichun’s customer receives a materially superior product at a lower price.

Lead Times: Standard configurations: 3–6 weeks (single-core cables are faster to manufacture than multi-core). Custom specifications: 6–10 weeks. European equivalent: 16–24 weeks.

Unit Pricing: A Nexans 12/20 kV BUFLEX-SC 1×95 mm² quoted at €85–110/meter can be sourced from Feichun at €42–60/meter—a 45–55% saving. For a 900-meter three-phase circuit, total savings: €38,700–€45,000.

Termination Savings: FC-EZS™ reduces termination time by 40–50% and termination failure rate by 85–95%. For a mobile substation operator performing 50+ terminations per year, this represents thousands of euros in avoided rework and hundreds of hours of saved labour.

Technical FAQ: Termination, Routing, and Performance

Is FC-EZS™ compatible with standard MV termination kits (3M, Raychem/TE, Ensto)?

Yes. FC-EZS™ semi-conductive layer dimensions, surface finish, and stripping characteristics are designed for compatibility with all major MV termination kit manufacturers. The FC-EZS™ stripped insulation surface meets the surface smoothness requirements of 3M Cold Shrink, Raychem/TE Connectivity heat-shrink, and Ensto separable connectors. Feichun has tested compatibility with over 20 major termination kit product lines and maintains a compatibility database available to customers upon request. If you use a specific termination kit brand, Feichun’s application engineers can confirm compatibility before production.

Can I use BUFLEX-SC for three-phase power by running three single-core cables in trefoil?

Yes, this is the primary intended application. Three BUFLEX-SC cables are routed together in trefoil formation (touching, with phases arranged at 120° to each other) for three-phase power delivery. Trefoil formation provides partial electromagnetic field cancellation between phases, reducing external EMI emissions. Derating factors for grouped cables should be applied per IEC 60502-2 or local installation standards. Feichun provides derating tables for trefoil and flat-spaced configurations in the cable’s technical datasheet.

What is the maximum short-circuit current rating?

Short-circuit current rating depends on conductor cross-section, fault duration, and initial conductor temperature. For a 95 mm² Tongling copper conductor at 80°C initial temperature with 1-second fault duration, the short-circuit current rating is approximately 12.8 kA (calculated per IEC 60949). Tongling copper’s lower normal operating temperature (due to lower resistance) provides additional thermal headroom—the conductor starts from a lower initial temperature, allowing it to absorb more fault energy before reaching the 250°C maximum temperature limit. Feichun provides exact short-circuit ratings for every conductor size and voltage rating in the cable’s technical documentation.

How do I select between copper wire braid and copper tape screening?

Use copper wire braid for applications requiring frequent handling, tight bending, and flexibility: switchgear routing, mobile jumper cables, festoon systems, and any application where the cable is coiled, uncoiled, or bent during its operational life. Use copper tape spinning for fixed installations where maximum earth-fault current capacity, 100% electromagnetic shielding, and minimum screen impedance are required: permanent substation connections, underground cable runs, and EMI-sensitive installations near communication equipment.

Can Feichun supply BUFLEX-SC with flame-retardant PUR for indoor installations?

Yes. Standard BUFLEX-SC PUR compound is self-extinguishing per IEC 60332-1 (single cable flame test). For installations requiring IEC 60332-3 (bunched cable flame test) compliance—typically indoor substations, data centres, and building risers—Feichun offers an enhanced flame-retardant PUR formulation designated FC-ASB-FR™. This formulation maintains full aramid reinforcement performance while achieving IEC 60332-3 Category C compliance. Low-smoke, zero-halogen (LSZH) PUR variants are also available for tunnel and enclosed-space applications requiring IEC 61034 (smoke density) and IEC 60754 (halogen content) compliance. FR and LSZH variants require 8–12 week lead times.

Does FC-EZS™ affect the cable’s partial discharge performance during operation?

No. FC-EZS™ technology modifies only the adhesion interface between the outer semi-conductive layer and the EPR insulation. The semi-conductive layer’s electrical properties (volume resistivity, dielectric constant, carbon black loading) are unchanged. The layer maintains perfect electrical contact with the insulation surface throughout the cable’s operational life—confirmed by 25-year equivalent thermal aging tests showing zero delamination and zero increase in partial discharge activity. The FC-EZS™ controlled-adhesion interface is designed to separate cleanly only when deliberately scored and peeled during termination; it does not separate during normal operation under any combination of temperature, vibration, or mechanical stress.

What is the minimum order quantity for custom voltage ratings or conductor sizes?

Standard configurations (6/10 kV and 12/20 kV at common conductor sizes 25–120 mm²): no minimum order quantity; available from stock or 3–4 week production. Custom configurations (unusual voltage ratings, non-standard conductor sizes, special PUR colours, LSZH variants): minimum order quantity typically 500 meters. For very specialised requirements (1.8/3 kV or 18/30 kV ratings, conductor sizes above 185 mm²): minimum 1,000 meters. Contact Feichun’s engineering team for specific availability and MOQ confirmation.