What Are the Insulated Wires Types And What Scenes Are They Used In?
In modern power systems and electronic devices, insulated wires are indispensable fundamental components. They encase conductors with insulating materials to prevent electrical leakage, short circuits, or the risk of electric shock while ensuring efficient energy transmission. With technological advancements and diverse scenario requirements, the materials and designs of insulated wires have continually evolved. This article systematically explains the definition of insulated wires, insulated wires types, and range of application cases, aiming to provide guidance for engineering selection and practical common applications.
I. Definition and Core Functions of Insulating Wires
Definition：Insulated wires consist of a core made from conductive metal (such as copper conductor or aluminum) enclosed by one or more layers of non-conductive material (electrical insulation). Their core functions include:
● Electrical Isolation: Preventing current flow to the external environmental condition or short-circuiting between electrical conductors.
● Mechanical Protection: Resisting physical wear, chemical corrosion, and environmental impacts (like humidity and high temperatures).
● Safety Protection: Reducing the risk of electric shock, thus safeguarding personnel and equipment.
Key Performance Requirements for Wire Insulation Materials
● Dielectric Strength: The ability to resist breakdown under high voltage.
● Temperature Resistance: Stability under a wide range of temperatures.
● Flame Retardancy: Inhibiting flame spread to prevent fire escalation.
● Flexibility: Suitability for bending or mobile scenarios.
● Environmental Adaptability: Chemical resistance to UV radiation, oil, acids, and alkalis.
II. Cable Insulation Types (Classified by Insulation Material)
Insulation material is the key factor determining electrical wire performance. Here are six mainstream types of insulation and their characteristics:
Polyvinyl Chloride (PVC) Insulated Wires
Definition: Electrical Wires with Polyvinyl Chloride insulation, known for low cost and wide electrical application.
Characteristics:
● Advantages: Good flame retardancy, acid and alkali insulation resistance, and ease of processing.
● Disadvantages: Limited temperature resistance (long-term use ≤70°C), releases toxic gases at high temperatures.
Application Cases:
● Household Circuits: BV (copper core PVC insulated wire) used for wall sockets and lighting circuits.
● Low Voltage Application: BVR (multi-strand flexible electrical wire) suitable for frequently bent distribution box connections.
Cross-linked Polyethylene (XLPE) Insulated Wires
Definition: Polyethylene treated through chemical or physical cross-linking processes, enhancing heat resistance and mechanical strength.
Characteristics:
● Advantages: High-temperature tolerance (90~125°C), aging chemical resistance, high current capacity.
● Disadvantages: Complex processing, higher cost than semi-rigid PVC.
Application Cases:
● High Voltage Transmission: YJV (XLPE insulated power cable) used in urban grids above 10kV.
● Industrial Equipment: Motor winding electrical wires withstand high temperatures from frequent start-ups.
Rubber Insulated Wires
Definition: Flexible wires using natural or thermoplastic rubber (e.g., neoprene insulation) .
Characteristics:
● Advantages: Excellent flexibility, retains elasticity at cold extreme temperatures (-40°C).
● Disadvantages: Poor oil abrasion resistance, susceptible to hydrocarbon solvent corrosion.
Application Cases:
● Mobile Equipment: YZ common type rubber cables for temporary generator connections on construction sites.
● Mining Machinery: YC heavy-duty rubber-sheathed cables adapt to harsh environments with frequent dragging.
Polyethylene (PE) Insulated Wires
Definition: Insulated with Polyethylene, available in low-density (LDPE) and high-density (HDPE) forms.
Characteristics:
● Advantages: Excellent dielectric constant properties, moisture resistance to chemicals, lightweight.
● Disadvantages: Flammable, requires flame retardant additives.
Application Cases:
● Communication Cables: HYA telephone lines use PE insulation to reduce signal loss.
● Buried Cables: Rural grid installations use PE layers to resist soil corrosion.
Silicone Rubber Insulated Wires
Definition: Insulated with silicone rubber material, offering broad temperature adaptability.
Characteristics:
● Advantages: Wide temperature range (-60~200°C), UV resistance, non-toxic.
● Disadvantages: Low mechanical strength, requires braided reinforcement.
Application Cases:
● High-Temperature Equipment: Oven and welding machine internal wiring withstands continuous high temperatures.
● Aerospace: Aircraft engine peripheral wiring operates stably across extreme temperature variations.
Mineral Insulated (MI) Cables
Definition: Fire-resistant electrical cables with magnesium oxide powder as insulation and copper sheath.
Characteristics:
● Advantages: Extremely fire-resistant (withstands flames over 1000°C), non-smoke, non-toxic.
● Disadvantages: High rigidity, large bending radius, complex electrical installation.
Application Cases:
● Fire Systems: BTTZ cables used for fire alarms and emergency lighting circuits.
● Nuclear Power Plants: Electrical cables within containment structures pass severe LOCA (Loss-of-Coolant Accident) testing.
III. Other Classification Methods and Application Requirement of Cable Insulation
By Voltage Level
● Low Voltage Cables (≤1kV): Such as BV wire for home renovation.
● Medium Voltage Cables (6~35kV): YJV22 armored cables for city distribution networks.
● High Voltage Cables (≥110kV): Submarine transmission uses XLPE insulation with tri-extrusion technology.
By Structural Design
● Shielded Cables: KVVP control cables feature a copper wire braid layer to counter electromagnetic interference.
● Armored Cables: YJV22 with a steel tape outer layer offers physical damage resistance, suitable for direct burial or tunnel installation.
IV. In-depth Analysis of Typical Industrial Applications
Case 1: Data Center Flame-retardant Cables
● Requirement: High-density server rooms require fire-resistant, low-smoke cables.
● Selection: ZR-YJV (flame-retardant XLPE insulated cables) paired with halogen-free sheaths to minimize smoke toxicity during fires.
Case 2: New Energy Vehicle High-voltage Harnesses
● Requirement: EV motors and batteries need to withstand high voltages (600V+) and frequent vibrations.
● Selection: Silicone rubber insulated wires (e.g., FLRY-B) with TPE sheaths, balancing temperature resistance and flexibility.
Case 3: Offshore Wind Power Salt Spray-resistant Cables
● Requirement: Option for cables within offshore wind turbine towers must resist high humidity and salt spray corrosion.
● Selection: HDPE insulation + galvanized steel tape armored cables with anti-corrosion coating.
V. Future Development Trends of Electrical Wire Insulation
● Eco-friendly Materials: Promotion of halogen-free flame-retardant (LSZH) and biodegradable insulation materials.
● High Performance: Nano-modification enhances the temperature and mechanical strength of insulation materials.
● Smart Technology: Built-in fiber-optic sensors for real-time monitoring of flexible cable temperature and aging status.
The selection of insulated wires needs to comprehensively consider scenario demands (such as voltage, temperature, environment), cost, and safety standards. From PVC to mineral-insulated underground cables, each material offers unique advantages and limitations. As renewable energy and smart grids emerge, insulation technologies will continue to innovate, providing robust support for the efficiency and safety of power systems.
