Guide to Selecting and Safely Installing Armored Cable

Have you ever worried about the safe and stable operation of power systems in harsh environments? Are you searching for a cable solution that can withstand various challenges and ensure uninterrupted power supply? Armored cables might be the answer to your concerns.

Often described as the "steel guardian" of power transmission, armored cables provide reliable electricity supply in demanding conditions thanks to their durable construction. This article explores the selection, applications, and installation considerations of armored cables to help you address various power challenges.

Understanding Armored Cables

Armored cables, as the name suggests, feature one or more layers of metal armor protection added to standard cables. Typically constructed from steel wire or steel tape, this armor layer effectively resists mechanical damage, chemical corrosion, and other potential threats. The core remains copper conductors for power transmission, insulated with XLPE for safety and stability. A PVC inner sheath provides additional protection for the insulation and conductors, while the steel wire armor offers robust mechanical protection. The outermost PVC outer sheath provides extra defense against moisture and chemical erosion.

Exceptional Characteristics of Armored Cables

The popularity of armored cables stems from their unique advantages:

• Durability: The armor layer provides superior mechanical protection against compression, impact, punctures, and other external damage, ensuring safe operation in challenging environments.
• Corrosion Resistance: The armor layer offers protection against chemical erosion, extending cable lifespan.
• EMI Shielding: The armor layer effectively shields against electromagnetic interference, maintaining stable and reliable power transmission.
• Flame Retardancy: Some armored cables use flame-retardant materials to prevent fire spread and reduce fire risks.

Applications of Armored Cables

Thanks to their exceptional performance, armored cables find widespread use in demanding environments:

• Underground cable systems: Resistant to soil corrosion and mechanical damage, making them ideal for subterranean installations.
• Industrial facilities: Withstand heavy machinery pressure and chemical exposure, ensuring stable power supply in manufacturing plants.
• Construction sites: Endure harsh conditions while providing reliable power for equipment.
• Transportation infrastructure: Commonly used in railways and subways for signaling systems and power equipment.
• Power stations: Tolerate high temperatures and humidity in generation facilities.
• Outdoor locations and high-risk workshops: Resist various environmental challenges for external equipment.
• Cable conduits: Provide additional protection when installed in piping systems.

Types of Armored Cables

• PVC-sheathed armored cables: Feature excellent abrasion and corrosion resistance, making them a common choice.
• LSZH-sheathed armored cables: Use low-smoke zero-halogen materials that produce minimal smoke and no toxic gases when burned, suitable for environmentally sensitive locations.

Selection Criteria for Armored Cables

Choosing appropriate armored cables requires careful consideration of several factors:

1. Certification standards: In the UK, select cables with BASEC certification meeting BS5467 standards for EPR or XLPE-insulated, PVC-sheathed low-voltage SWA cables. International standards may vary.
2. Cable dimensions: Consider conductor count, length, and overall diameter based on application requirements.
3. Sheath material: PVC suits general environments, while LSZH is preferable where smoke and toxicity are concerns.
4. Conductor material: Typically copper for optimal conductivity and corrosion resistance.
5. Operating temperature: Ensure the cable's temperature range matches application needs.
6. Voltage rating: Select cables with appropriate voltage ratings for the electrical system.

Installation Guidelines

Proper installation is crucial for armored cable performance:

1. Cable support: Adequate support prevents stress on glands and damage from cable weight.
2. Gland connections: Use proper glands and maintain electrical continuity in metal enclosures.
3. Underground installation: Bury at sufficient depth (typically 450-600mm) with protective measures like sharp sand bedding and warning tapes.
4. Grounding: Always ground the armor to meet automatic disconnection requirements.
5. Testing: Comprehensive post-installation testing by qualified electricians is mandatory.

Cutting Techniques

Specialized tools and methods ensure safe armored cable cutting:

1. Use dedicated cable cutters or approved alternatives like side cutters or hacksaws.
2. Follow safety procedures: precise measurement, proper blade adjustment, secure clamping, and careful cutting.

Bending Radius

Maintain minimum bending radii (typically 6-8 times cable diameter) to prevent damage during installation.

Outdoor Installation Considerations

Use IP-rated cables and glands for outdoor or harsh environments, ensuring connections provide adequate protection against moisture and contaminants.

Conclusion

Armored cables represent an optimal solution for power transmission in challenging conditions. Understanding their characteristics, applications, selection criteria, and installation requirements ensures reliable electrical system performance in demanding environments.