Fire Resistant Shielded Twisted Pair NH-RVSP 2 * 1.0/1.5/2.5 Shielded Wire

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2025-09-15 09:04:41

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Fire Resistant Shielded Twisted Pair NH-RVSP 2*1.0/1.5/2.5 Shielded Wire: Comprehensive Details

I. Product-Specific Details

1. Technical Specifications and Electrical Performance

The Fire Resistant Shielded Twisted Pair NH-RVSP 2*1.0/1.5/2.5 shielded wire is engineered to meet stringent performance standards for safety-critical communication and control systems, with technical specifications tailored to ensure reliability in fire emergencies and harsh operating environments.

Voltage and Current Ratings: The cable is rated for 300/500V, making it suitable for low-voltage signal transmission and control circuits. Current-carrying capacity varies by conductor size: the 21.0mm² variant handles up to 10A, ideal for low-power devices like smoke detectors; 21.5mm² supports 14A, suitable for elevator control systems; and 2*2.5mm² carries 20A, designed for fire pump controls and industrial sensors. These ratings are validated under ambient temperatures of 30°C, with derating factors of 0.9 at 40°C and 0.8 at 50°C to prevent overheating.

Electrical Resistance: At 20°C, the DC resistance of the stranded Copper Conductors is 18.1Ω/km for 1.0mm², 12.1Ω/km for 1.5mm², and 7.41Ω/km for 2.5mm². This low resistance ensures minimal signal loss over distances up to 100 meters, critical for maintaining communication integrity in large buildings or industrial facilities.

Fire Resistance Performance: A defining specification is the cable’s ability to operate under fire conditions. It meets GB/T 19666-2019 (Chinese standard) and EN 50264-2-1 (European standard), withstanding 750°C ± 50°C flames for 90 minutes while maintaining circuit integrity (insulation resistance ≥1MΩ). During this period, the cable continues transmitting signals, supporting emergency response systems like fire alarms and elevator recall functions.

Shielding Effectiveness: The tinned copper braid or aluminum-polyester (Al-PE) Tape Shield provides 85–90% coverage, achieving a shielding effectiveness of ≥80dB at frequencies 1MHz–1GHz. This blocks electromagnetic interference (EMI) from Power Cables, motors, and radio frequency sources, ensuring signal-to-noise ratio (SNR) remains above 40dB for clear communication in noisy industrial environments.

Mechanical Flexibility: The cable’s minimum bending radius is 4× the outer diameter for static installation and 6× for dynamic bending (repeated movement). For example, the 2*2.5mm² variant (outer diameter 9mm) has a static bending radius of 36mm, allowing installation in tight spaces like wall cavities or cable trays without damaging conductors or insulation.

2. Conductor and Insulation Materials

Conductors: The cable features high-purity Stranded Copper Conductors (purity ≥99.95%) with a conductivity of ≥100% IACS. Stranding enhances flexibility: 1.0mm² conductors consist of 19 strands (0.26mm diameter each), 1.5mm² of 19 strands (0.32mm), and 2.5mm² of 49 strands (0.25mm). This fine-stranded design allows the cable to bend repeatedly without conductor breakage, a key advantage in installations requiring routing around corners or through narrow conduits. Tinning (tin layer thickness ≥0.005mm) protects copper from oxidation, ensuring long-term conductivity even in humid environments.

Insulation: The primary insulation is cross-linked polyethylene (XLPE) or halogen-free fire-retardant polyvinyl chloride (FR-PVC), both treated with non-halogen flame retardants (e.g., aluminum hydroxide, magnesium hydroxide). XLPE offers superior thermal stability, operating at -40°C to 90°C continuously, while FR-PVC is more cost-effective with a range of -15°C to 70°C. Both materials resist tracking (surface degradation from electrical discharges) and have a dielectric strength of ≥20kV/mm, preventing insulation breakdown under voltage stress.

Outer Sheath: The sheath is made of low-smoke zero-halogen (LSZH) polyolefin, a halogen-free material that emits <50% light transmittance smoke and <0.5% toxic gas (chlorine, fluorine) when burned—critical for maintaining visibility and safe evacuation during fires. It contains flame retardants (e.g., red phosphorus) to achieve V-0 flammability rating (UL94 standard), self-extinguishing within 10 seconds of removing the ignition source. The sheath also resists abrasion (wear index ≤20mg/1000 cycles per IEC 60811-2-1) and moisture (water absorption ≤0.5%/24h), suitable for both dry indoor and damp outdoor installations.

3. Structural Design and Shielding

The NH-RVSP cable’s structure is optimized for signal integrity, fire resistance, and durability:

Conductor Layer: Stranded Copper Conductors are twisted together to form a Flexible Core, with each strand coated in a thin layer of antioxidant to prevent corrosion.

Insulation Layer: XLPE or FR-PVC Insulation (thickness 0.6mm for 1.0mm², 0.7mm for 1.5mm², 0.8mm for 2.5mm²) is extruded over each conductor, ensuring uniform coverage with eccentricity ≤10% to avoid weak points.

Twisted Pair Formation: The two Insulated Conductors are twisted with a controlled lay length (10–15× conductor diameter) to reduce crosstalk. For 21.0mm², the lay length is 16mm; for 22.5mm², it is 24mm. This twisting cancels out electromagnetic interference between the two conductors, improving signal stability.

Shielding Layer: A tinned copper braid (0.1mm wire diameter, 48–64 braid ends) or Al-PE tape (0.05mm aluminum + 0.02mm polyester) is applied over the twisted pair. Braid coverage is 85–90%, ensuring EMI protection while maintaining flexibility. For applications requiring higher shielding, double-layer shielding (braid + tape) is available, increasing effectiveness to ≥90dB.

Outer Sheath: The LSZH polyolefin sheath (thickness 1.0mm for 1.0mm², 1.2mm for 2.5mm²) is extruded over the shield, forming a continuous protective layer that bonds tightly to prevent moisture ingress. The sheath’s surface is often ribbed to enhance grip during installation.

This layered design balances compactness and performance: the 21.0mm² cable has an outer diameter of 6–7mm, 21.5mm² of 7–8mm, and 2*2.5mm² of 8–10mm, allowing installation in standard 16mm–20mm conduits.

4. Special Features and Applications

Key Features:

Non-Halogen Fire Safety: The LSZH sheath and insulation emit minimal smoke and toxic gases, complying with IEC 61034 (smoke density) and IEC 60754 (acid gas emission), making it suitable for enclosed spaces like high-rise buildings and subway systems.

Long-Term Fire Performance: Unlike flame-retardant cables that merely resist ignition, NH-RVSP maintains functionality during fires, meeting the "circuit integrity" requirement for life safety systems.

EMI Immunity: The shielding ensures reliable operation in environments with high electromagnetic noise, such as near power transformers, welding equipment, or radio towers.

Weather Resistance: The sheath resists UV radiation (passing 1000-hour QUV test per ASTM G154) and temperature extremes, enabling outdoor use in solar-powered security systems or outdoor fire alarm networks.

Chemical Resistance: The materials resist degradation from common building chemicals (e.g., cleaning agents, plaster) and industrial fluids (mild acids, oils), suitable for hospitals, laboratories, and factories.

Applications:

Fire Alarm Systems: Connects smoke detectors, heat sensors, manual call points, and fire alarm control panels (FACP) in commercial buildings, ensuring rapid fire detection and alert transmission.

Emergency Control Networks: Transmits signals for elevator recall (to ground floor), emergency lighting activation, and fire damper operation, critical for safe evacuation during crises.

Industrial Safety Systems: Used in chemical plants, refineries, and Power Stations to link gas detectors, emergency shutdown (ESD) valves, and safety PLCs, where fire and EMI resistance prevent catastrophic failures.

Transportation Hubs: Installed in airports, railway stations, and subway systems to support communication between security cameras, public address systems, and emergency response teams.

Healthcare Facilities: Wiring in hospitals for nurse call systems, medical gas monitoring, and emergency power distribution, where low smoke emission protects patients and staff.

5. Manufacturing Process and Quality Control

The production of NH-RVSP cables involves precision manufacturing and rigorous testing to ensure compliance with safety standards:

Conductor Stranding: High-purity copper rods are drawn into fine wires, which are then twisted in a stranding machine. Tension is controlled to avoid strand breakage, and the twisted conductors are annealed (heated to 300°C) to soften the copper, enhancing flexibility.

Insulation Extrusion: Each conductor is insulated with XLPE or FR-PVC using a tandem extrusion line. The process maintains a constant temperature (120°C for FR-PVC, 200°C for XLPE) to ensure uniform thickness. XLPE is cross-linked via steam (180°C, 2MPa) to form a thermoset structure with heat resistance.

Pair Twisting: The two insulated conductors are twisted in a cabling machine with precise lay length control, using servo motors to maintain consistency. This step reduces crosstalk and ensures balanced impedance.

Shielding Application: For braided shields, tinned Copper Wires are woven around the twisted pair using a braiding machine with adjustable tension to achieve 85–90% coverage. For Al-PE tape shields, the tape is helically wrapped with 20% overlap and bonded with heat to prevent delamination.

Sheath Extrusion: The LSZH polyolefin sheath is extruded over the shield using a low-pressure extrusion process to avoid damaging the shielding. The sheath is cooled in a water bath and then cured at 80°C to enhance mechanical properties.

Quality Control Tests:

Conductor Tests: Conductivity (≥100% IACS), tensile strength (≥200MPa), and elongation (≥30%) are verified for each batch.

Insulation Tests: Dielectric strength (≥20kV/mm), insulation resistance (≥1000MΩ·km), and thermal aging (130°C for 168 hours, no cracking) are checked.

Fire Resistance Tests: Samples undergo 750°C flame exposure for 90 minutes, with insulation resistance and continuity monitored throughout.

Shielding Effectiveness: Measured using a network analyzer to ensure ≥80dB at 1MHz–1GHz.

Mechanical Tests: Bending (10,000 cycles at 6× diameter), abrasion (≥10,000 cycles), and impact resistance (-40°C, 1kg weight dropped from 1m) are validated.

Each cable is marked with the manufacturer’s name, type (NH-RVSP), size, voltage rating, and production date for traceability.

II. General Product Information

1. Packaging Specifications

NH-RVSP cables are packaged to protect against damage during storage and transportation while ensuring easy handling:

Standard Lengths: Available in 100m, 200m, and 500m reels. Smaller lengths (10m, 20m) are offered for sample testing or small-scale installations.

Reel Types: Wooden reels (ISPM 15 certified for international shipping) or plastic reels are used, with flanges to prevent cable slippage. Reel diameters range from 300mm (100m) to 600mm (500m), with a steel core for structural support.

Protection: The cable is wrapped in moisture-resistant plastic film to prevent dust and water ingress. For long-term storage, reels are placed in cardboard cartons lined with foam to cushion against impacts.

Labeling: Each reel/carton is labeled with:

Product name: Fire Resistant Shielded Twisted Pair NH-RVSP

Specifications: 21.0mm², 21.5mm², or 2*2.5mm²

Length and net weight

Standards compliance (GB/T 19666, EN 50264)

Fire rating (90 minutes at 750°C)

Manufacturer contact information and batch number

Custom Packaging: For bulk orders, cables can be packaged in wooden crates with internal bracing to prevent movement during sea freight.

2. Transportation and Logistics

The cables are classified as non-hazardous goods (UN 3082 exempt for limited quantities), enabling flexible transportation:

Domestic Shipping: By road (trucks with covered trailers) or rail. Delivery times: 1–3 days for regional orders, 5–7 days for nationwide.

International Shipping: Sea freight (2–6 weeks) in 20ft/40ft containers, with reels secured using steel straps to prevent shifting. Air freight (3–5 days) is available for urgent orders, with reels packed in shrink-wrapped pallets.

Handling Precautions: Cables must be stored upright to avoid reel deformation. During loading/unloading, forklifts with reel handlers are used to prevent bending or crushing. Exposure to temperatures below -20°C or above 60°C during transit is avoided to protect insulation and sheath materials.

Documentation: Includes commercial invoice, packing list, material safety data sheet (MSDS), and certificate of conformity (CoC) for customs clearance. For EU shipments, CE marking and Declaration of Performance (DoP) are provided.

3. Order Processing and Delivery

Order Placement: Customers can order via email, phone, or online portal. Required details: cable size, length, quantity, and delivery address. Custom lengths (e.g., 300m) are available with a 5% surcharge.

Lead Times: Standard orders (≤5000m) ship within 3–5 business days. Large orders (>10,000m) may require 7–10 days to manufacture.

Payment Terms: 30% deposit for bulk orders, balance due before shipment. Letters of credit (L/C) are accepted for international transactions.

Tracking: Once shipped, customers receive a tracking number via email, allowing real-time monitoring of shipment status through the logistics provider’s portal.

4. Sample Policy

Sample Availability: Free samples (1m length) of 21.0mm² and 21.5mm² are available upon request, with customers covering only shipping costs. 2*2.5mm² samples incur a nominal fee (≈$20) to cover material costs.

Processing Time: Samples are shipped within 24–48 hours of request, via express courier (DHL, FedEx).

Sample Certification: Each sample includes a test report with key parameters (conductor resistance, insulation resistance, shielding effectiveness) for customer verification.

5. Warranty and After-Sales Support

Warranty: 5-year warranty against manufacturing defects. If the cable fails due to material or workmanship issues within this period, the manufacturer will replace it free of charge, including shipping.

Technical Support: A dedicated team provides installation guidance, including:

Recommended bending radius and conduit sizes

Termination methods (crimping, soldering) for shielded connections

Compatibility with connectors (e.g., M12, terminal blocks)

Troubleshooting: 24/7 hotline support for issues like signal interference or insulation damage. For on-site problems, technical engineers can be dispatched within 48 hours (domestic) or 72 hours (international) for a service fee.

Maintenance Guidelines: Customers receive a manual with recommendations for periodic inspection (annually):

Visual check for sheath damage or corrosion

Insulation resistance testing (≥100MΩ)

Shield continuity verification

Recall and Replacement: In the event of a safety-related defect, the manufacturer initiates a recall program, offering free replacement and on-site installation assistance.

Conclusion

The Fire Resistant Shielded Twisted Pair NH-RVSP 2*1.0/1.5/2.5 shielded wire is a critical component in safety-critical systems, combining fire resistance, EMI protection, and reliable signal transmission. Its non-halogen materials, robust shielding, and flexible design make it indispensable in environments where lives depend on uninterrupted communication during emergencies. Backed by stringent quality control, comprehensive packaging, and responsive after-sales support, this cable ensures long-term performance in the most demanding applications—from high-rise buildings to industrial facilities—setting a benchmark for safety and reliability in fire-resistant communication cables.