Surge protective component application guide - Self-restoring thermally activated overcurrent protectors |
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Recommendation ITU-T K.144, which is a part of the surge protective component application guide series, covers self-restoring thermally activated overcurrent protectors (OCPs). Unlike fuses and heat coils, which break the circuit, these series connected self-restoring thermally activated overcurrent protectors (OCPs) automatically reset when the electrical event causing the overcurrent stops, without the need for manual intervention.
Self-restoring thermally activated overcurrent protector (OCP) components operate by the increasing in resistance value, which reduces the circuit current when the overcurrent exceeds a given value for a sufficient time. The resistance transition is caused by the component body reaching a critical temperature caused by the i2R heating of the overcurrent flowing through the component. The generic name for components with this type of action is positive temperature coefficient (PTC) thermistors. Being thermally operated, these PTC thermistors generally do not operate for short duration electrical transients, such as coupled lightning currents, but will operate for longer term AC and DC overcurrents.
There are two types of material used to make PTC thermistors; ceramic and polymer. Many of the component parameters apply to the both types of material. Some parameters are specific to the material used and these differences are explained. This Recommendation describes positive temperature coefficient (PTC) thermistor construction, operation, production, ratings and characteristics and gives application examples. |
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Citation: |
https://handle.itu.int/11.1002/1000/14075 |
Series title: |
K series: Protection against interference |
Approval date: |
2019-11-13 |
Provisional name: | K.app16 |
Approval process: | AAP |
Status: |
In force |
Maintenance responsibility: |
ITU-T Study Group 5 |
Further details: |
Patent statement(s)
Development history
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Ed. |
ITU-T Recommendation |
Status |
Summary |
Table of Contents |
Download |
1
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K.144 (11/2019)
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In force
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here
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here
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here
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ITU-T Supplement
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Title
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Status
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Summary
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Table of contents
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Download
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K Suppl. 3 (10/2015)
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ITU-T K.20, K.21, K.45, K.82 – Additional criteria to protect telecommunication cabling during a power cross event
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In force
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here
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here
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here
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K Suppl. 8 (11/2017)
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Resistibility analysis of 5G systems
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In force
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here
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here
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here
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K Suppl. 9 (05/2019)
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5G technology and human exposure to radiofrequency electromagnetic fields
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In force
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here
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here
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here
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K Suppl. 10 (11/2017)
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Analysis of electromagnetic compatibility aspects and definition of requirements for 5G mobile systems
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In force
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here
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here
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here
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K Suppl. 13 (12/2021)
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Radiofrequency electromagnetic field (RF-EMF) exposure levels from mobile and portable devices during different conditions of use
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In force
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here
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here
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here
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K Suppl. 14 (09/2019)
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The impact of RF-EMF exposure limits stricter than the ICNIRP or IEEE guidelines on 4G and 5G mobile network deployment
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In force
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here
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here
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here
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K Suppl. 16 (10/2022)
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Electromagnetic field compliance assessments for 5G wireless networks
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In force
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here
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here
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here
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K Suppl. 19 (09/2019)
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Electromagnetic field (EMF) strength inside underground railway trains
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In force
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here
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here
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here
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K Suppl. 29 (07/2022)
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Electromagnetic field strength inside and outside of electric vehicles using wireless power transfer technology
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In force
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here
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here
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here
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Title |
Approved on |
Download |
Mitigation measures for telecommunication installations – Chapter 10
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2006
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here
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Mitigation measures for telecommunication installations
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2004
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here
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Earthing and bonding
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2003
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here
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Guide to the use of ITU-T Publications produced by Study Group 5 aimed at achieving Electromagnetic Compatibility and Safety
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2002
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here
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Earthing of telecommunication installations
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1976
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here
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