Characteristics and ratings of solid-state@ self-restoring overcurrent protectors for the protection of telecommunications installations (Study Group 5)
This Recommendation applies to 2-terminal@ series connected@ solid-state@ self-restoring overcurrent protectors (OCPs) used in surge protective devices (SPDs) and telecommunications equipment. These OCPs are directly connected to a device or equipment port and provide overcurrent protection and coordination functions for telecommunications installations during lightning surges and AC power faults@ in accordance with [b-ITU-T K.11]. The port test levels and criterion are defined by [ITU-T K.20]@ [ITU-T K.21] and [ITU-T K.45]@ as appropriate. [ITU-T K.44] supports these three equipment performance ITU-T Recommendations with test circuit details and application guidance. This Recommendation provides the basic requirements@ and parameter tests@ for OCPs used in the protection of telecom installations. This Recommendation covers the following types of solid-state@ self-restoring OCP: a) polymer positive temperature coefficient (PPTC) thermistors; b) ceramic positive temperature coefficient (CPTC) thermistors; c) electronic current limiters (ECLs). It does not deal with: a) mountings and their effect on OCP performance@ the test results only apply for the mounting method used for that test; b) system signal performance such as insertion loss@ see [b-ITU-T G.117]; c) mechanical dimensions; d) RoHS requirements; e) electrical overload; f) quality assurance requirements@ see [IEC 60738-1]; g) specific cases of user agreed and regional values.