Triaxial coax cable. Applications? 1

Triax has been traditionally a must for instrumentation, particularly electrometers. The reason is that coax, as used in instrumentation, requires current flow through the shield as well in addition to causing an imbalance in the impedance to the rest of the world.

Triax shields both leads, thus making it a balanced impedance. Additionally, the shield can now be independently driven to reduce coupling to external sources as well as minimizing displacement currents during charge measurements. TTFN

If you happen to have a chance to look at a Cat 5e or Cat 6 cable tester, you will probably find the cable between the test box and the RJ45 plug is a triaxial cable. It is the only reasonable way to ensure a good impedance match between the jack and the test box.