Understanding AS/NZS 1802 Type 245 1.1 kV Mining Cables

Introduction

Mining cables play a critical role in the mining industry, providing essential power distribution in challenging environments where standard cables would quickly fail. The AS/NZS 1802 standard ensures these cables meet strict safety and performance requirements necessary for the harsh conditions of mining operations.

Type 245 mining cables are specifically designed with enhanced durability, flexibility, and safety features to withstand the demanding conditions of both underground and surface mining operations.

Application Scenarios

Underground Mining

These cables excel in powering essential underground machinery including:

• Longwall shearers (primary application)

• Continuous miners

• Drills and boring equipment

• Water pumps and drainage systems

• Conveyor systems for material transport

Surface Mining

On the surface, these cables are deployed for:

• Mobile equipment power supply

• Semi-mobile processing equipment

• Heavy machinery operations

• Temporary power distribution networks

Harsh Environments

Type 245 cables are engineered to withstand:

• Severe abrasion from rock surfaces

• Crushing forces and mechanical stress

• Chemical exposure (oils, fuels, minerals)

• Extreme temperature variations

• Wet and humid conditions

Temporary Power Distribution

Their flexibility makes them ideal for:

• Movable equipment installations

• Frequently reconfigured mining sections

• Advancing work faces where power needs shift

• Quick deployment and retrieval operations

Electrical and Physical Specifications

Voltage Rating

• Type 245.1: 1.1 kV (1100 Volts) - Low voltage mining applications

• Type 245.3: 3.3 kV (3300 Volts) - Medium voltage mining applications

• Type 245.6: 6.6 kV (6600 Volts) - Higher voltage mining applications

Conductor

• Material: Flexible stranded tinned annealed copper

• Configuration: Available in various cross-sectional areas (16mm² to 150mm²)

• Strand configuration: Highly flexible with numerous fine strands (e.g., 133/0.40 means 133 strands of 0.40mm diameter)

• Benefits: Excellent conductivity, corrosion resistance, and superior flexibility

Insulation

• Material: Ethylene Propylene Rubber (EPR)

• Thickness: Varies by voltage rating (1.6-2.3mm for Type 245.1, 3.0mm for Type 245.3, 5.0mm for Type 245.6)

• Properties: Outstanding thermal stability, electrical insulation properties, and resistance to moisture

Cable Components

• Conductor Screen: Semiconductive compound (for 3.3kV and above)

• Insulation Screen: Semiconductive elastomer

• Cradle Separator: Semiconductive PCP (polychloroprene)

• Overall Core Screen: Semiconductive PCP filling and covering

• Earth Conductors: 3 interstitial semiconductive PCP covered flexible stranded tinned copper conductors

• Pilots: 3 central extensible EPR covered flexible stranded tinned copper conductors for monitoring and control

Sheath

• Material: Heavy-duty PCP (polychloroprene) sheath

• Optional: Heavy-duty CPE/CSP (chlorinated polyethylene/chlorosulfonated polyethylene) upon request

• Function: Provides excellent mechanical protection, flame resistance, and environmental sealing

Temperature Range

• Typical operating range: -25°C to +90°C

• Allows for operation in various climates and mining depths

Physical Characteristics

• Overall Diameter: Ranges from approximately 42.6mm to 85.8mm depending on type and conductor size

• Weight: From approximately 235 kg/100m to 1210 kg/100m

Standards Compliance

• AS/NZS 1802:2003: Specific standard for electric cables - Reeling and trailing

• AS/NZS 1125: General electrical testing standards

• AS/NZS 3808: Insulation and sheathing materials

• AS/NZS 5000.1: Electric cables - Polymeric insulated

Common Challenges and FAQ

Q1: What happens if the cable insulation gets damaged in a mining environment?

A: Damaged insulation can lead to short circuits, equipment failure, or even fires. In mining environments, this presents a particular hazard due to potentially explosive atmospheres. Regular inspection and immediate replacement are critical. The semiconductive layers in these cables help provide some protection by ensuring even electrical field distribution, but physical damage must be addressed promptly.

Q2: Can these cables withstand water exposure or flooding?

A: Yes, Type 245 mining cables are designed to be water-resistant with their robust PCP sheathing. However, prolonged submersion, especially if the cable has any physical damage, could compromise integrity. While they can operate in wet conditions, protective measures like proper drainage and avoiding standing water will extend their service life.

Q3: How flexible are these cables? Can they be frequently moved?

A: The design includes highly flexible copper conductors (with up to thousands of fine strands) and resilient EPR insulation, making them exceptionally flexible. The reinforcement with open-weave braid enhances durability during movement. These cables are specifically designed for applications like longwall shearers where constant movement and flexing occur.

Q4: Are there any special installation practices needed for these cables?

A: Proper routing to avoid sharp bends, using appropriate cable hangers, and avoiding mechanical stress points is essential. For moving applications, adequate slack should be provided, and proper reeling systems should be employed. Cable supports should be spaced to prevent excessive sagging, particularly for heavier gauge cables.

Q5: How do these cables perform under mechanical stress, such as being run over by vehicles?

A: The robust PCP sheath provides good mechanical protection, but excessive crushing force can still damage the cable. While they're designed to withstand reasonable mechanical stress, protective ramps or trenching are recommended for high-traffic areas. The textile reinforcement layer helps provide additional resistance to crushing forces.

Q6: What is the purpose of the pilot conductors in these cables?

A: The three central extensible pilots serve two critical functions: earth continuity monitoring for safety and providing control circuits for equipment operation. These pilots allow for integrated control and monitoring systems without requiring separate cables, which is particularly valuable in mining environments where cable management is challenging.

Q7: What certifications or testing should users check before purchasing?

A: Always verify third-party certification for compliance with AS/NZS 1802 and ensure the manufacturer provides testing data for:

• Flame resistance and fire propagation characteristics

• Electrical performance under load

• Mechanical durability testing results

• Resistance to oils, chemicals, and environmental factors

• Flexibility and bending radius testing

Q8: How do I select the right cable size for my application?

A: Selection depends on several factors:

• Current requirements of the equipment

• Voltage drop considerations (especially for longer runs)

• Environmental factors (temperature, installation method)

• Mechanical stress expectations

• Frequency of movement/reeling

For critical applications, consulting with a qualified electrical engineer familiar with mining operations is recommended to ensure proper sizing.

Understanding these specialized cables ensures optimal performance, safety, and longevity in the demanding conditions of mining operations.