BS 7835 XLPE/LSZH Medium Voltage 19/33 (36)kV Power Cable Flame Retardant, Low Smoke, Zero Halogen, Underground & Ducting Applications
Application | Power cables for power networks, underground and in cable ducting, in installations with potential threat to life and equipment in the event of fire, smoke and toxic fumes emissions. |
Characteristics | Voltage Rating Uo/U (Um): 19/33 (36) kV |
Construction | Conductor: Class 2 stranded copper according to BS EN 60228 (prev. BS 6360) |
Standards | BS 7835, IEC/EN 60228, IEC/EN 60502-2 |
DIMENSIONS
No. of Cores | Nominal Cross Sectional Area (mm²) | Nominal Diameter Under Armour (mm) | Nominal Diameter Over Armour (mm) | Nominal Diameter Overall (mm) | Nominal Weight (kg/km) | |
1 | 70 | 32.6 | 36.6 | 41.0 | 2300 | |
1 | 95 | 34.3 | 38.3 | 42.9 | 2650 | |
1 | 120 | 35.9 | 39.9 | 44.5 | 3000 | |
1 | 150 | 37.5 | 42.5 | 47.3 | 3500 | |
1 | 185 | 39.3 | 44.3 | 49.3 | 4000 | |
1 | 240 | 41.7 | 46.7 | 51.7 | 4650 | |
1 | 300 | 44.2 | 49.2 | 54.4 | 5450 | |
1 | 400 | 47.3 | 52.3 | 57.7 | 6350 | |
1 | 500 | 50.5 | 55.5 | 61.1 | 7600 | |
1 | 630 | 54.2 | 59.2 | 65.0 | 9150 | |
1 | 800 | 60.5 | 65.5 | 71.6 | 11100 | |
1 | 1000 | 65.0 | 70.0 | 76.5 | 13400 | |
3 | 50 | 65.1 | 71.4 | 78.2 | 9150 | |
3 | 70 | 68.8 | 75.1 | 82.1 | 10300 | |
3 | 95 | 72.6 | 78.9 | 86.1 | 11600 | |
3 | 120 | 76.3 | 82.6 | 90.0 | 12800 | |
3 | 150 | 79.3 | 85.6 | 93.2 | 14050 | |
3 | 185 | 83.4 | 89.7 | 97.5 | 15650 | |
3 | 240 | 88.8 | 95.1 | 103.3 | 18200 | |
3 | 300 | 93.9 | 100.2 | 108.8 | 21100 | |
3 | 400 | 100.8 | 107.1 | 116.1 | 24200 |
When it comes to medium voltage power distribution, safety, reliability, and performance are crucial. The BS 7835 XLPE/LSZH 19/33 (36)kV power cable has emerged as a leading choice for underground and ducting applications, particularly in environments where fire safety and low smoke emissions are critical.
Where Can BS 7835 Medium Voltage Cables Be Applied?
Underground and Ducting Installations: BS 7835 is ideal for installations with strict fire safety requirements, such as:
Industrial Complexes: Factories, refineries, and chemical plants.
Substations and Power Networks: For reliable medium voltage power distribution.
Tunnels and Underground Infrastructure: High fire safety and low smoke emissions prevent casualties during fire incidents.
Commercial Buildings: High-rise offices, shopping centers, and critical installations.
Case Study: Indonesia
In Jakarta’s new metro line, BS 7835 XLPE/LSZH cables were installed in underground tunnels. Their LSZH sheath reduced smoke emission during accidental fires, protecting both commuters and equipment. The cable’s flame-retardant design ensured compliance with Indonesia’s fire safety regulations.
How Does BS 7835 Compare to Other Medium Voltage Cables?
Feature | BS 7835 XLPE/LSZH | Traditional PVC Cables | Standard XLPE Cable |
|---|---|---|---|
Fire Performance | Flame retardant, low smoke, zero halogen | Limited flame retardancy, emits toxic gases | Flame retardant, moderate smoke |
Environmental Safety | LSZH reduces halogen release | PVC releases HCl and other toxic gases | Typically PVC or non-LSZH outer layer |
Mechanical Protection | AWA/SWA armour | Optional | Optional |
Applications | Underground, ducts, high-risk areas | General-purpose | Underground, moderate safety |
UV Resistance | Yes | Sometimes | Sometimes |
Temperature Rating | 0–90°C fixed | 0–70°C fixed | 0–90°C fixed |
BS 7835 outperforms conventional PVC cables in fire safety and smoke reduction, making it the preferred choice for critical installations.
What Are the Common Questions About BS 7835 Cables?
How Should I Install BS 7835 Cables in Ducts and Underground?
Ensure minimum bending radius is respected (use cable former near joints).
Maintain proper separation from other services to prevent electrical interference.
Use appropriate cable cleats or supports for single-core and three-core installations.
Apply derating factors for ambient temperature, soil thermal resistivity, and burial depth.
Can BS 7835 Be Used in High-Risk Fire Areas?
Yes, LSZH outer sheath and flame-retardant XLPE insulation reduce the risk of fire propagation and toxic gas emissions. This makes BS 7835 suitable for tunnels, industrial plants, and densely populated urban areas.
What Are the Conductor Types and Their Benefits?
BS 7835 uses Class 2 stranded copper conductors, which offer:
Excellent flexibility for installation.
High conductivity for minimal energy loss.
Compatibility with medium voltage terminations and joints.
How Do I Choose the Right Cable Size?
Consider:
Required load current (refer to electrical characteristics table).
Installation environment (air, ground, duct).
Derating factors (temperature, burial depth, soil resistivity).
Are There Real-Life Performance Examples?
Yes, in Surabaya, BS 7835 cables were installed in an industrial park for medium-voltage distribution. They performed reliably under high thermal loads and challenging soil conditions, with zero fire or smoke incidents reported.
What Are the Best Practices for BS 7835 Cable Installation?
Planning and Route Survey: Map the route to avoid mechanical damage during installation.
Proper Handling: Avoid sharp bends and excessive pulling tension.
Jointing and Termination: Use compatible medium voltage terminations to maintain insulation integrity.
Periodic Inspection: Check for signs of mechanical damage or thermal stress, particularly in high-load applications.
Documentation: Maintain installation records, including derating factors and joint locations.
Why Choose BS 7835 for Your Next Project?
Safety First: LSZH and flame-retardant design protect life and assets.
Versatile Applications: Suitable for underground, ducts, industrial, and high-rise environments.
Long-Term Reliability: Copper conductors and XLPE insulation ensure decades of stable performance.
Compliance with Standards: Meets BS 7835, IEC/EN 60228, and IEC/EN 60502-2, reducing regulatory risks.
Call-to-Action: For industrial or urban medium voltage projects, BS 7835 XLPE/LSZH cables offer a safe, reliable, and compliant solution. Contact a certified distributor or engineering consultant to assess your project’s cable requirements and ensure optimal performance.
