Motivation

Protection against overvoltages and overcurrents of telecommunication installation and equipment is achieved with adequate resistibility level of both equipment and lines insulation and proper installation of suitable protective devices. Changes have occurred in the resistibility requirements and protective devices technology.

These changes require studies to ensure that the recommendations on protective devices fit the needs of the operators and the user of telecommunication networks.

The following Recommendations, in force at the time of approval of this Question, fall under its responsibility:

• K.11, K.12, K.28, K.30, K.36, K.55, K.65 and K.69.

Question

The objective of this question is to establish Recommendations for specifications, test methods and principles of application for protective components and assemblies intended to mitigate effects of lightning, power induction, ESD, fast transients and power contacts that may cause permanent damage. These protective components and assemblies are related to both telecommunication and power supply circuits of telecommunication equipment.

Study items to be considered include, but are not limited to:

• The limits for minimum and maximum d.c. sparkover voltage, and maximum impulse sparkover voltage before and after life tests;
• Coordination of overcurrent protection components in the MDF and the equipment;
• The introduction of solid-state overcurrent protection components;
• Coordination of overvoltage and overcurrent protection;
• Considerations intended to facilitate the selection of most effective protection method (e.g. source and intensity of overvoltages and overcurrents).

Tasks

Tasks include, but are not limited to:

• New Recommendations on the application of new protection elements and/or assemblies;
• New Recommendations on the basis of the following criteria:
  • Basic requirements, based on K.11 and K.36;
  • Product requirements, based on K.12, K.28, K.30, K.55 and K.65.
• New Recommendation on Self restoring overcurrent protectors;
• New Recommendation on Characteristics of metal oxide varistors for the protection of telecommunications installations;
• Maintenance of the existing Recommendations under the responsibility of the Question;
• Possible revision of Volume VIII of the Directives.

An up-to-date status of work under this Question is contained in the SG 5 Work Program (use URL as shown in the table below).

Relationships

Recommendations:

• K-series

Questions:

• 4, 5, 6 and 15/5

Study Groups:

• none

Standardization bodies:

• IEC SC 37A, IEC SC 37B, IEC TC 64, IEC TC 81, CENELEC TC 81X, IEC SC 77B