Comprehensive technical guide to flame-retardant, halogen-free medium voltage cables with dual waterblocking technology. Manufactured in accordance with IEC 60502-2 and VDE 0276-620 standards for power distribution networks.
What is N2XS(FL)H Medium Voltage Power Cable?
Comprehensive technical guide to flame-retardant, halogen-free medium voltage cables with dual waterblocking technology. Manufactured in accordance with IEC 60502-2 and VDE 0276-620 standards for power distribution networks.
1. Overview: Purpose and Applications
The N2XS(FL)H cable designation represents a sophisticated medium voltage power distribution cable engineered for demanding industrial and infrastructure applications. This cable type combines cross-linked polyethylene (XLPE) insulation with a Low Smoke Zero Halogen (LSZH) outer sheath and incorporates dual-layer waterblocking technology, making it suitable for both internal and external installations where fire safety and environmental protection are paramount.
According to industry specifications referenced by reelingcable.com, medium voltage cables in this category are particularly valuable for power distribution in utility networks, energy generation facilities, and industrial infrastructure requiring continuous, reliable power transmission under challenging environmental conditions.
Designation Breakdown: N2XS(FL)H
| Code Element | Designation | Technical Meaning |
|---|---|---|
| N | Standard Design | German (DIN/VDE) standard construction |
| 2X | XLPE Insulation | Cross-linked polyethylene, 90°C rated |
| S | Copper Screen | Copper wire and tape metallic screening |
| (F) | Longitudinal Waterblocking | Swellable tape/powder barrier |
| (L) | Radial Waterblocking | Laminated Al/PET tape barrier |
| H | LSZH Sheath | Low Smoke Zero Halogen outer sheath |
Primary Application Scenarios
The N2XS(FL)H cable finds extensive application across diverse sectors where medium voltage power distribution is critical. As documented by amplexmining.com.au, specialized cables in industrial environments must withstand severe physical punishment including constant abrasion, crushing forces, and exposure to environmental extremes while maintaining electrical integrity.
Substations and generation facilities requiring fire-safe cabling
Cable ducts, direct burial, and tunnel installations
Manufacturing plants, data centers, life sciences
Internal installations with fire regulation compliance
2. Technical Characteristics and Performance Parameters
The N2XS(FL)H cable is engineered to deliver exceptional electrical performance while maintaining mechanical durability under demanding operational conditions. The following specifications represent standard manufacturing parameters in accordance with international standards.
Voltage Ratings and Electrical Parameters
| Parameter | 6/10 (12) kV | 8.7/15 (17.5) kV | 12/20 (24) kV | 18/30 (36) kV |
|---|---|---|---|---|
| Rated Voltage U₀/U (Um) | 6/10 (12)kV | 8.7/15 (17.5)kV | 12/20 (24)kV | 18/30 (36)kV |
| AC Test Voltage (5 min) | 21kV | 30.45kV | 42kV | 63kV |
| Lightning Impulse Test | 75kV | 95kV | 125kV | 170kV |
| Insulation Thickness (Nominal) | 3.4mm | 4.5mm | 5.5mm | 8.0mm |
Thermal Performance Thresholds
Current Carrying Capacity Reference
The following ampacity values are calculated for cables installed in air at an ambient temperature of 30°C with conductor operating temperature of 90°C. Actual current ratings should be verified against specific installation conditions.
| Conductor Size (mm²) | In Air (A) | Direct Buried (A) | In Duct (A) | Short Circuit 1s (kA) |
|---|---|---|---|---|
| 35 | 170 | 155 | 140 | 5.0 |
| 50 | 200 | 180 | 165 | 7.2 |
| 70 | 245 | 220 | 200 | 10.0 |
| 95 | 295 | 265 | 240 | 13.6 |
| 120 | 340 | 300 | 275 | 17.2 |
| 150 | 385 | 340 | 310 | 21.5 |
| 185 | 440 | 385 | 350 | 26.5 |
| 240 | 515 | 445 | 405 | 34.4 |
| 300 | 585 | 505 | 460 | 43.0 |
| 400 | 680 | 575 | 525 | 57.3 |
| 500 | 775 | 645 | 590 | 71.6 |
| 630 | 885 | 725 | 665 | 90.2 |
📊 Derating Factors
Apply correction factors for ambient temperatures above 30°C: at 40°C use 0.91, at 50°C use 0.82, at 60°C use 0.71. For grouped cables, apply additional derating based on spacing and configuration per IEC 60287.
3. Material Structure and Construction
The N2XS(FL)H cable employs a layered construction approach with each component specifically engineered to address particular electrical, mechanical, or environmental requirements. As detailed by cranecable.com, port and industrial cables must endure continuous mechanical stress while maintaining electrical integrity, making proper material selection essential for operational longevity.
Conductor — Class 2 Stranded Copper
Compacted stranded copper conductor per EN 60228 Class 2, providing optimal conductivity-to-size ratio. Stranded construction enhances flexibility while maintaining current-carrying capacity for medium voltage applications.
Conductor Screen — Semiconductive Compound
Extruded semiconductive layer applied in triple extrusion process with insulation. Creates uniform electric field distribution and eliminates air gaps between conductor and insulation.
Insulation — Cross-Linked Polyethylene (XLPE)
High dielectric strength XLPE insulation providing exceptional thermal stability up to +90°C continuous operation. Offers superior moisture resistance and aging characteristics compared to EPR alternatives.
Insulation Screen — Semiconductive Layer
Strippable semiconductive compound applied over insulation. Maintains uniform electric field and facilitates cable termination and jointing operations.
Longitudinal Waterblocking (F) — Swellable Tapes
Water-swellable tapes and/or powders applied above and below metallic screen. Upon moisture contact, material expands to form barrier preventing water propagation along cable length.
Metallic Screen — Copper Wires + Copper Tape
Helically applied copper wire screen combined with counter-helix wound copper tape. Provides EMI shielding, contains electric field within core, and serves as fault current return path.
Radial Waterblocking (L) — Aluminium Laminate
Aluminium tape tightly bonded to sheath creates radial water barrier. Prevents moisture ingress in event of mechanical sheath damage (puncture, abrasion, or impact).
Outer Sheath — LSZH Compound
Low Smoke Zero Halogen thermoplastic sheath per IEC 60754. CPR compliant, flame retardant, UV resistant for internal and external installation. Traditionally red color for identification.
Material Performance Comparison
| Property | XLPE (N2XS_H) | EPR Alternative | PVC Alternative |
|---|---|---|---|
| Max Operating Temp | 90°C | 90°C | 70°C |
| Dielectric Constant (εr) | 2.3 | 3.0–3.5 | 4.0–8.0 |
| Dielectric Loss (tan δ) | 0.0004 | 0.005 | 0.08 |
| Water Absorption | Very Low | Low | Moderate |
| Flexibility | Moderate | High | Moderate |
4. Standards Compliance and Certifications
The N2XS(FL)H cable is manufactured to meet stringent international standards ensuring consistent quality, performance, and safety across global installations. According to research from amplexmining.com.au, compliance with recognized cable standards provides assurance that cables will perform reliably in demanding industrial conditions, with rigorous testing requirements covering everything from insulation integrity to mechanical protection.
Primary Manufacturing Standards
| Standard | Designation | Scope |
|---|---|---|
| IEC 60502-2 | Power Cables with Extruded Insulation | Cables 6 kV to 30 kV — Construction, dimensions, test requirements |
| VDE 0276-620 | German National Standard | Power cables — MV cables with polymeric insulation |
| HD 620 | CENELEC Harmonized Document | European MV cable harmonization standard |
| EN 60228 | Conductor Classes | Conductors of insulated cables (Class 1/2 specifications) |
Fire Performance Standards
| Standard | Test Method | Requirement |
|---|---|---|
| IEC/EN 60332-1-2 | Single cable flame propagation | Flame retardant — Self-extinguishing |
| IEC/EN 60332-3-24 | Bundled cables Category C | Limited flame spread in grouped installation |
| IEC/EN 61034-1/2 | Smoke density measurement | Low smoke emission ≥ 60% light transmittance |
| IEC/EN 60754-1/2 | Halogen gas emission | Zero halogen — pH ≥ 4.3, conductivity ≤ 10 µS/mm |
Construction Products Regulation (CPR) Compliance
For installations within the European Union where cables enter or are installed inside buildings, CPR compliance under EU Regulation 305/2011 is mandatory. The N2XS(FL)H cable with LSZH sheath achieves Euroclass ratings suitable for CPR requirements, enabling continuous cable runs from external to internal environments without jointing at the point of entry.
-s1, d1, a1 (typical)
Suitable for outdoor exposure
Years expected service life
5. Safety Thresholds and Operational Limits
Understanding and adhering to the safety thresholds of N2XS(FL)H cables is essential for maintaining system integrity and preventing premature failure. As noted in mining cable guidance from Feichun Cables, industrial cables must be rated appropriately for their operating environment, with safety margins built into specifications to account for transient conditions and installation variations.
Critical Temperature Thresholds
⚠️ Maximum Temperature Limits
Exceeding rated temperatures accelerates insulation degradation following the Arrhenius equation. Every 10°C increase above rated temperature approximately halves expected cable service life. Continuous operation at +90°C conductor temperature is the design limit; emergency overload to +130°C should be limited to 8-hour duration maximum with subsequent derating.
| Operating Condition | Temperature Limit | Duration Limit | Effect on Service Life |
|---|---|---|---|
| Normal Operation | +90°C | Continuous | Design basis (30+ years) |
| Emergency Overload | +130°C | 8 hours maximum | Limited cycles permitted |
| Short Circuit | +250°C | 5 seconds maximum | Post-fault inspection required |
| Minimum Installation | -20°C | N/A | Avoid bending below this temp |
Electrical Safety Parameters
| Parameter | Value | Notes |
|---|---|---|
| Insulation Resistance (MΩ·km) | ≥ 1000 | At 20°C, minimum acceptable value |
| Maximum Screen Voltage | ≤ 65V | Touch voltage limit under fault conditions |
| Partial Discharge Extinction | ≤ 5 pC | At 1.5 × U₀, factory test requirement |
| Water Tree Resistance | High | TR-XLPE grade where specified |
Mechanical Safety Limits
| Conductor Size | Min Bending Radius (Fixed) | Min Bending Radius (During Install) | Max Pulling Tension |
|---|---|---|---|
| ≤ 150 mm² | 12 × OD | 15 × OD | 50 N/mm² conductor area |
| 185 – 400 mm² | 15 × OD | 20 × OD | 50 N/mm² conductor area |
| ≥ 500 mm² | 18 × OD | 25 × OD | 40 N/mm² conductor area |
6. Installation Precautions and Best Practices
Proper installation procedures are critical to achieving the full design life and performance of N2XS(FL)H cables. Research from miningcable.cl and industry sources emphasizes that cable selection is only part of the equation—correct installation techniques, environmental considerations, and ongoing maintenance determine actual operational performance and longevity.
Pre-Installation Requirements
Cable Inspection
Visually inspect drum and cable for transport damage. Check seal integrity on cable ends. Verify cable marking matches specification. Perform insulation resistance test before installation.
Temperature Verification
Confirm ambient temperature exceeds -20°C before handling or bending cable. Store cable drums in temperature-controlled environment if installation will occur in cold conditions. Pre-warm cable if necessary.
Route Preparation
Clear cable route of sharp edges, debris, and obstructions. Install appropriate cable supports, guides, and rollers. Verify duct internal diameter and clear obstructions. Calculate pulling tension and compare to limits.
Installation Method Guidelines
| Installation Type | Key Requirements | Special Considerations |
|---|---|---|
| Direct Burial | Min 700mm depth, cable route marking, sand bedding 100mm above/below | Thermal resistivity of backfill affects ampacity; use thermal sand where required |
| Cable Duct | Use cable lubricant, respect pulling tension, verify duct integrity | Waterblocking essential for ducts subject to flooding; FL version mandatory |
| Cable Tray | Adequate support spacing, separation from other services, fire barriers | LSZH sheath required for indoor cable trays; maintain cleating intervals |
| Tunnel/Gallery | Proper ventilation for heat dissipation, fire compartmentalization | Consider forced cooling for heavily loaded installations |
Critical Installation Cautions
⚠️ Critical Installation Precautions
Never exceed bending radius limits — Insulation damage may not be immediately visible but will cause premature failure. Avoid sidewall pressure during pulling operations. Seal cable ends immediately after cutting to prevent moisture ingress. Ground screens at both ends for cables > 25m to prevent circulating currents. Test before energization — perform DC hipot or VLF testing per manufacturer recommendations.
Jointing and Termination
Cable jointing and termination must be performed by qualified personnel using manufacturer-approved accessories. The dual waterblocking layers (FL) require specific joint designs to maintain water barrier integrity across the joint. Heat-shrink or cold-shrink terminations should be specified for the LSZH sheath type.
7. Frequently Asked Questions (FAQ)
8. Common Cable Variants and Alternatives
The N2XS(FL)H belongs to a family of medium voltage cables sharing common design principles but optimized for different installation requirements or conductor materials.
Sheath Type Variants
| Designation | Sheath Material | Fire Performance | Typical Application |
|---|---|---|---|
| N2XS(FL)H | LSZH (Zero Halogen) | Low smoke, flame retardant, CPR compliant | Internal/external, buildings, tunnels |
| N2XS(FL)Y | PVC | Standard flame retardant | External only, direct burial |
| N2XS(FL)2Y | PE/HDPE | Standard, UV resistant | External, high UV exposure areas |
Waterblocking Variants
| Designation | Waterblocking | Protection Level | Recommended For |
|---|---|---|---|
| N2XSH | None | Standard sheath only | Dry indoor installations |
| N2XS(F)H | Longitudinal only | Prevents axial water propagation | Ducts with occasional moisture |
| N2XS(FL)H | Longitudinal + Radial | Complete water barrier | Flooded ducts, water table burial, critical installations |
Conductor Type Variants
| Copper Version | Aluminium Version | Size Comparison | Weight Comparison |
|---|---|---|---|
| N2XS(FL)H | NA2XS(FL)H | Cu ~35% smaller OD | Al ~50% lighter |
| N2XS(F)H | NA2XS(F)H | For equivalent current | For equivalent current |
| N2XSH | NA2XSH | Cu preferred for limited space | Al preferred for long runs |
Request Technical Specifications or Quotation
Anhui Feichun Special Cable Co., Ltd. manufactures N2XS(FL)H cables to IEC 60502-2 and VDE 0276-620 standards. Our technical team can provide detailed datasheets, dimensional drawings, and competitive pricing for your project requirements.
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