PTFE Rods for Electrical Insulators
PTFE rod as a machinable high-voltage, high-frequency dielectric insulator.
Why PTFE for electrical insulation
PTFE is one of the best solid dielectric insulators available. Its volume resistivity exceeds 10¹⁸ Ω·cm, its dielectric strength is very high, and — unusually — its dielectric constant stays flat at 2.1 from mains frequency all the way up to gigahertz, with an extremely low dissipation factor. That frequency stability is why PTFE rod is machined into insulators, standoffs, connector bodies and antenna components for RF and high-frequency electronics, not just low-frequency switchgear. It also tolerates heat to 260°C, so the insulator will not soften or fail near hot conductors the way many plastics would.
Dimensional stability matters
A machined insulator has to hold its dimensions to keep creepage and clearance distances correct. PTFE's near-zero water absorption means it does not swell in humid or wet conditions, so a PTFE standoff machined to size stays to size — a real advantage over nylon insulators, which absorb moisture and change both their dimensions and their electrical properties over time.
Grades for electrical work
For electrical insulation, virgin (unfilled) PTFE is normally specified, because fillers such as carbon or bronze are electrically conductive and would ruin the dielectric performance. Glass-filled PTFE can be used where extra mechanical strength is needed and the slight change in electrical properties is acceptable. Confirm the working voltage and frequency with us and we will advise the correct grade and section.
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Tell us the part, the media and the temperature, and we'll confirm the right PTFE grade to machine from.