scope:

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.