Mica tape is a high-temperature, high-dielectric insulation made by laminating thin mica paper to a support (typically woven glass cloth or PET film) with a heat-resistant binder such as silicone or epoxy. In cable factories and motor shops it’s best known as the wrap that lets circuits keep working during a fire and insulation stay stable under heat and voltage stress. In short: when failure isn’t an option, mica tape is the layer you add.
• Mica paper (the working layer). Produced from phlogopite or muscovite mica that’s pulped, formed, and often calcined to improve thermal stability.
• Reinforcement. Most fire-survival cable grades use glass cloth as the carrier—this is the “glass mica tape”you'll see on datasheets—while some motor grades use PET film.
• Binder. Silicone or epoxy systems bind the mica paper to the carrier and influence flexibility, flame performance, and processing behavior.
| Type | Typical Thermal Stability | Where it shines | Notes |
| Phlogopite mica tape | Excellent integrity at very high temperatures (commonly specified for fire-resistant cable cores) | Mica cable tape for power/LSZH fire-survival constructions; furnace leads | Better stability at red heat than muscovite. |
| Muscovite mica tape | High dielectric strength; stable up to lower red-heat range | Motors/generators, appliances | Lower dehydroxylation temperature than phlogopite. |
| Synthetic (fluorophlogopite) | Very clean, consistent; high purity | Specialty electronics | Higher cost; limited supply. |
Mineralogically, phlogopite retains structural integrity at higher temperatures than muscovite, which is why phlogopite mica tape dominates fire-resistant cable designs.
In fire-resistant (fire-survival) cables, glass mica tape is helically wrapped over conductors to maintain circuit integrity during fire tests such as IEC 60331 (cables must continue to operate under flame/heat for a defined duration) and to help control flame spread under IEC 60332. Without that layer, polymeric insulation alone can carbonize and fail.
Typical constructions use one or more half-lap wraps of glass mica tape beneath XLPE/LSZH insulation; during fire, the inorganic mica barrier prevents flashover so the circuit stays alive long enough for evacuation or shutdown procedures.
Benefits
• High dielectric strength & low loss: makes mica tape electrical insulation reliable at elevated temperatures.
• Fire barrier: mineral layer resists flame, supporting IEC fire-survival performance.
• Thermal endurance: phlogopite grades tolerate severe heat; muscovite offers strong electrical properties.
• Chemical & UV stability: inorganic backbone resists many environments compared with organic films.
Trade-offs
• Flex & handling: high-mica, low-binder tapes can be stiffer and require controlled wrap tension.
• Cost vs. commodity wraps: performance is far above paper or standard glass tapes, and pricing reflects that. (See price drivers below.)
1.Fire-resistant power, control, and signal cables—the classic mica tape application. One or two helical wraps under XLPE/LSZH help the core pass circuit-integrity tests.
2.Motors and generators—turn insulation, slot liners, and end-windings in high-voltage machines often incorporate mica because organic systems alone can't take the thermal/electrical stress.
3.Transformers, appliance leads, and furnace wiring—where sustained high temperature and dielectric strength are mandatory.
When suppliers say mica cable tape, they usually mean phlogopite-glass tapes optimized for cable wrapping lines; glass mica tape emphasizes the glass cloth carrier; and mica tape electrical insulation is a broader umbrella term covering both cable and rotating-machine grades.
• Phlogopite glass-mica tape (silicone-bonded): the industry workhorse for IEC 60331 fire-survival cables.
• Muscovite glass-mica tape: preferred in some motor/generator builds for dielectric performance.
• Reinforcement options: woven glass (best at high heat) vs. PET film (higher flexibility, lower fire rating).
• Binder systems: silicone (heat-stable), epoxy (strong bond), hybrid systems for specific process windows.
There isn't a single mica tape price—it varies by:
• Mica type & calcination (phlogopite vs. muscovite; synthetic grades cost more)
• Reinforcement (glass cloth vs. PET), binder chemistry, and mica content
• Tape geometry (thickness, roll width/length, slit tolerance) and wrap behavior
• Compliance (e.g., tested to IEC 60331/60332, UL/EN listings)
• Market factors (origin of mica, logistics, MOQs)
Supply chains matter: a large share of natural mica originates from India, China, and Madagascar, with well-documented traceability and ethical-sourcing challenges that can influence availability and price. Programs like the Responsible Mica Initiative exist to improve conditions.
• Fire rating target: If you need circuit integrity per IEC 60331 (e.g., 90–120 min), start with phlogopite glass-mica tape qualified for that test.
• Voltage & dielectric margin: Match mica content and thickness to your impulse and AC stress levels (especially in MV motors).
• Mechanical processing: For high-speed cable tapers, specify consistent slit width, roll OD, and winding density.
• Environment: For hot, dirty, or chemically aggressive installs, prioritize silicone-bonded, glass-reinforced variants.
• Documentation: Ask vendors for full test reports (IEC 60331/60332), dielectric data, and recommended wrap overlaps.
• Higher survival time in real fires (keeps alarms, pumps, and critical circuits alive)
• Less derating at temperature compared with organic films
• Cleaner failure modes—inorganic barrier limits conductive carbon paths
• Compatibility with LSZH cable systems and modern motor insulation stacks.
Is all mica tape the same?
No. “Glass mica tape”for cables is different from PET-reinforced motor tapes; binders, thickness, and mica type vary by use.
Can I use muscovite where specs call for phlogopite?
Generally not for fire-survival cables—phlogopite's high-temperature stability is the reason it's specified.
What wrap overlap is typical?
Cable makers often use 50% overlap for consistent barrier thickness; always follow the product datasheet and your fire-test plan.
Whether you call it mica tape, mica cable tape, or mica tape electrical insulation, the product is a mineral-based safety layer that delivers electrical integrity at temperatures where most polymers simply can't cope. Choose the mica type and construction that fit your target standard and process—and let the mica tape price reflect total risk reduction, not just roll cost. For fire-resistant cables, phlogopite glass-mica tape remains the benchmark solution.
