Telecommunications gas tube apparatus and composition for use therewith

摘要

A telecommunications gas tube apparatus (40) which is suitable for connection to a gas discharge tube (12) and which comprises an electrically non-linear resistive element (45) prepared from an electrically non-linear composition which comprises a polymeric component and a particulate filler. The composition has an initial resistivity rho i at 25 DEG C of at least 10<9> ohm-cm, and is such that a standard device containing the composition has an initial breakdown voltage VSi, and after the standard device has been exposed to a standard impulse breakdown test, the device has a final breakdown voltage VSf which is from 0.7VSi to 1.3VSi. In addition, the composition in the device has a final resistivity rho f at 25 DEG C of at least 10<9> ohm-cm. Such compositions are useful in providing both vent-safe and fail-safe protection to a gas discharge tube (12).