What Are High Voltage (HV) Coaxial Connectors, Cables, & Cable Assemblies?

There are several high voltage (HV) applications, such as in instrumentation, imaging inspection, medical, aerospace, and military/defense that pose the problem of connecting high voltage power supplies, signal generators, and instruments to devices-under-test (DUTs) and other equipment. High quality coaxial connectors and cables are naturally well suited to carrying low to medium voltages, and there are some coaxial cable and connector types that have even been used for HV applications without having originally been designed for these applications. However, there is a limitation to the voltage levels that typical coaxial components can be used for safely and reliably. Hence, there are High Voltage Connectors & Adapters, High Voltage Coaxial Cable, High Voltage DC Block, and other components designed specifically for HV applications that offer higher voltage levels and other attractive features compared to standard coaxial components.

Some HV applications have voltage levels that reach over 100,000 volts, or even higher. Many of these applications may be sensing for HV power distribution, such as with utility grids, but there are many scientific research and medical applications that also make use of extremely high voltages. Many of these applications require equipment to handle voltage levels above 20k volts or even 40k volts. As with many coaxial components, HV coaxial cable and connectors are typically made with special polyethylene dielectric, which exhibits high dielectric breakdown and insulation characteristics. The shielding of the coaxial components is a natural electrical shield to prevent the high electrical potential of the inner conductor of the HV coaxial components from interacting with external conductors. Moreover, the shield of a coaxial cable intrinsically acts as a safety feature if the inner dielectric does fail, preventing direct exposure of high voltage conductors.

For extremely high voltage applications, some coaxial cable is built with a thicker dielectric core for enhanced dielectric insulation and breakdown levels. Moreover, these cables may even be built with a “corona shield” made with a thin layer of semiconductor material wrapped around the center conductor beneath the dielectric insulator. This is used to equalize the geometric voltage gradations around the center conductor and reduce the potential of generating coronal discharge.

Other important features of purpose built HV coaxial components are true operating ratings to certain HV levels, such as 10kV, 20kV, 30kV, 40kV, etc. Also, HV coaxial connectors and adapters are often hermetically sealed, which prevents off-gassing and diffusion common in HV applications. HV coaxial connectors are also designed differently than standard coaxial cables, with inset contacts with extended insulation to prevent accidental discharge from conductor contact and are also often designed to be relatively rugged and environmentally sealed.