TW200717008A - Dielectric test switch and earth leakage breaker - Google Patents

Abstract

To provide a construction of a dielectric test switch installed in an earth leakage breaker, the switch being small-sized and compact and allowing additional installation in a limited space within a main body housing of the breaker without changing the layout of principal parts. An earth leakage breaker installing an earth leakage tripping device including an earth leakage detection circuit 7 within a main body housing 12 of the breaker is equipped with a manually operated dielectric test switch 11 for disconnecting the earth leakage detection circuit from a main circuit on insulation and withstand voltage teat of the breaker. The dielectric test switch 11 has an assembly structure comprising a switch casing 13 of insulator having a partition wall 13c for separating poles, fixed electrode holders 15 holding pairs of fixed electrodes 14 for each pole, bridge type movable contacts 16 constructed of a leaf spring having a reversed V shape for each pole disposed opposing and above the fixed electrodes, a movable contact holder 17 holding the movable contacts for all poles together and contained in the switch casing slidably in the vertical direction, and an actuation head 17a continued from the contact holder and extending upward out of the switch casing. A hook at a tip of the actuation head is positioned in the vicinity of an opening in a cover of the main body housing of the breaker and is pushed down and pulled up manually from outside of the main body housing to close and open the dielectric test switch.