Mineral insulated cables (MICs) are widely used in fire protection systems, high-temperature environments, and critical power transmission applications due to their excellent fire and heat resistance and safety. Based on their structure and performance, MICs can be divided into rigid and flexible MICs.
I. Core Comparison
1. Structure and Material Differences
Rigid MICs
Conductor: Typically a single solid copper conductor with a rigid structure.
Insulation: Compacted with high-density magnesium oxide (MgO) powder to form a rigid insulation.
Sheath: The outer layer is a seamless copper tube or alloy metal sheath, providing mechanical protection and grounding.
Features: The overall structure is sturdy, but the large bending radius makes it difficult to lay flexibly.
Flexible MICs
Conductor: Made of multiple strands of fine copper wire, twisted together, offering high flexibility.
Insulation: Wrapped with mica tape or a flexible mineral compound. Some products also incorporate materials such as silicone rubber.
Jacket: The outer layer is typically wrapped with copper tape or a low-smoke, halogen-free polymer material, offering both flexibility and protection.
Features: Flexible structure, adaptable to complex wiring environments.
2. Mechanical Performance Comparison
Rigid cable: High compressive and tensile strength, but poor bending performance, requiring specialized tools for cutting or bending.
Flexible cable: Flexible and resilient, suitable for dynamic wiring or installation in confined spaces.
3. Fire and Temperature Resistance
Rigid cable: The magnesium oxide insulation layer has a melting point of up to 2800°C, offering a fire resistance limit of over three hours, and is smokeless and non-toxic.
Flexible cable: Fire resistance is slightly lower (typically 1-2 hours), but some products can meet high-level fire protection requirements through composite insulation.
4. Installation and Maintenance
Rigid cable: Installation requires specialized tools (such as hydraulic pliers), strict joint sealing requirements, and a long installation period.
Flexible cable: Supports on-site cutting, simplifies joint handling, and is suitable for quick installation or renovation projects.
II. Usage Scenario Analysis
1. Rigid Mineral Insulated Cable
Typical Applications:
High-temperature industrial equipment (e.g., metallurgical furnaces, boiler rooms).
Fire emergency power supply systems, nuclear power plant safety circuits.
Long-term fixed installations requiring extremely high fire resistance.
Advantages: Strong stability in extreme environments and long service life.
2. Flexible Mineral Insulated Cable
Typical Applications:
Power supply for mobile equipment (e.g., cranes, rail transit).
Complex wiring within buildings (e.g., high-rise building shafts, curved pipelines).
Temporary power supply scenarios requiring frequent line adjustments.
Advantages: Flexible installation, reduced construction costs, and adaptability to dynamic needs.
