How vacuum pressure affects feedthrough voltage ratings.
Electrical feedthroughs sold by AGP are rated for service in high vacuum environments with pressures of less than or equal to 1x10E-4 Torr (1.333x10E-6 bar), and with standard atmospheric pressures outside of the vacuum chamber — 760 Torr (1.013 bar)
Although glow discharge is a phenomenon used in many industrial and scientific applications like in the operation of neon and fluorescent lighting, cathode ray tubes, plasma-gas displays, plasma physics, sputter coatings, semiconductor etching, and analytical chemistry — it is highly undesirable and detrimental to in-vacuum electrical circuitry — this is especially so for high voltage devices and applications.
Glow discharge plasma is produced in low-pressure gas environments by applying a voltage differential between two electrodes — an electrical anode and cathode pair. The low-pressure gas inside a containment vessel will ionize and produce gas plasma at some key pressure and voltage threshold — losing all insulating properties and becoming electrically conductive.
The graph below depicts how the dielectric strength of air behaves with respect to pressure changes within a vacuum chamber. If producing low-pressure gas plasma is not your goal — for safety and preventing irreparable damage to sensitive electrical equipment — we recommend powering down all high voltage sources and electrical devices while your system transitions through this critical vacuum pressure range, commonly known as the glow discharge region.
