Extruded FEP Insulated Wires
FEP is the softest of the fluorocarbon co-polymers offered by Exotherm Cable and is,
beside an excellent insulation material, likely to be the most favorable fluoropolymer
for cable jackets.
FEP has excellent non-ageing characteristics and a broad useful temperature range from about -200ºC to +200ºC continuously. Used as insulation FEP passes several severe flame tests as for instance the IEEE 383 and has also the UL 94 V-0 rating. The chemical inertness of the material is excellent and is one of the most chemical resistant polymers.
Extruded FEP insulated high voltage wire and cable offers exceptional dielectric
strength without the disadvantages common to equally rated silicone rubber insulated
cables. As a result, cable assemblies or cable bundles are of smaller diameter and
therefore take up substantially less volume and have a smaller bend radius which
allows the designer to better utilize the space within the system. It has good corona
inception qualities and its construction gives it excellent durability and resistance
to dielectric/cooling fluid degradation.
Additionally, FEP insulation, being a harder material than silicone rubber, is not prone to pin-holing and high voltage punch-thru when the cable surface is abraded or when strands break during in-field service. FEP is also more resistant to damage when making contact with sharp edges. FEP cable should not only be considered for use in cable assemblies, but as high voltage hook-up wire within encapsulated high voltage power supplies, TWTs and transformers.
Low DC corona inception, particularly after numerous temperature cycles, is another advantage of FEP over silicone cables. PTFE tape wrapped cable, which is similar to FEP in dielectric strength and corona inception, is difficult to bond to because of its multiple spiral cross section, irregular surface and variations in diameter.
The material is excellent for use as a dielectric – it has got an excellent dielectric constant of 2.1, a high dielectric strength, excellent resistivity and an excellent dissipation factor of magnitude 0.0005. Its low dielectric constant is essentially constant with changing frequency or temperature.
Exotherm Instruments’s FEP wire meets the requirements of MIL-W-16878/11, 12 & 13
Properties of FEP Fluorocarbon Resin
|Physical, Thermal and Electrical Properties||Typical Values|
|Tensile Strength (PSI)||3,500|
|Flexual Modules (PSI)||90,000|
|Thermal Conductivity (cal/sec/cm°F)||6X10|
|Continuous Use Temperature (°C)||204|
|Melt Temperature (°C)||255–265|
|Low Temperature Limit (°C)||-240|
|Water Absorption (%)||<01|
|Dielectric Constant, 60-10 Hz||2.1|
|Dissipation Factor, 60-10 Hz||<.0007|
|Volume Resistivity (Ohms-Cm)||<10|
|Surface Resistivity (Ohms/Sq.)||<10|
|Cold Flow or Cut Through||Fair|
|Electro-Mechanical Stress Cracking||Excellent|
|Chemical-Mechanical Stress Cracking||Excellent|
Advantages of Extruded FEP wire over Wrapped PTFE WireExotherm Instruments produces these FEP wires using Conventional Hot Melt Extrusion process, which has several advantages over Wrapped PTFE wires as listed below.
- Uniform Diameter
- Smooth Outer Surface
- Strong bonding between Insulation and core conductor
- Easy stripping by Automatic stripping M/c or hand held stripper
- Can be produced in Continuous long length.
- Hook up Wire for Control Panels
- Wire Harness Assembly
- Motor & Transformer Lead wires
- Batteries, UPS & Invertors
- Plenum Cables
- Halogen Lamp Holders & Lanterns
- Electric Cooker, Micro-wave Oven, Electric Thermos, Air-Conditioning Equipment
- Computers, Laptops, PDA’s
- Medical and scientific instruments
- Aircraft Wiring, Defense & Signal Equipments.
- Process Instrumentation
- RTD, Thermocouples and Thermistors
- Sensors & Igniters
- Semiconductor & Electronics
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