IEEE 1458-2005 pdf download IEEE Recommended Practice for the Selection, Field Testing, and Life Expectancy of Molded Case Circuit Breakers for Industrial Applications
1. Overview
1.1 Scope
This standard provides a recommended procedure for the selection, application, and determination of theremaining life in molded case circuit breakers This recommended procedure is safe and easily understood.
1.2 Purpose
Molded case circuit breakers are one of the most widely used circuit protection devices in low-voltage (lessthan 1000 volt) applications. In spite of their wide use in industry, the average person specifying, installingoperating and maintaining these devices has less than a complete understanding of them, The purpose of thisdocument is to provide people who purchase or maintain molded case circuit breakers with a single document that includes the following information:
How molded case circuit breakers operate
How to correctly size and select molded case circuit breakers
How to safely maintain molded case circuit breakers
How to determine when a molded case circuit breaker must be replaced
2.Normative references
This standard shall be used in conjunction with the following publications. The following referenced docu-ments are indispensable for the application of this standard. For dated references, only the edition citedapplies. For undated references, the latest edition of the referenced document (including any amendments orcorrigenda)applies.
IEEE Std 242″, The Buff Book–EEE Recommended Practice for Protection and Coordination of Indus-trial and Commercial Power Systems.l, 2
IEEE Std 1015”The Blue Book-EEE Recommended Practice for Applying Low-Voltage CircuitBreakers Used in Industrial and Commercial Power Systems.
3.Molded case circuit breaker basics
This clause describes the basic components of a molded case circuit breaker and how the components work
3.1 Molded case circuit breaker basics
The topic of circuit breakers covers a very broad range of electrical devices, which have a number of thingsin common and an even larger number of dissimilar features and capabilities. The main groupings selectedto cover circuit breakers are listed here as an introduction, without defining or explaining the individuagroupings at this point:
Circuit breakers in general
Industrial molded case circuit breakers (600 V and below)
Miniature circuit breakers (240 V and below)
Generally speaking, a circuit breaker is a device that:
Provides protection
Opens and closes
Might be removable
Might be fixed
Might be installed by itself in an enclosure
Might be installed with other equipment
Is applied at many voltage levels
Circuit breaker definitions vary depending upon the source of the definition.
NEMA definition-A circuit breaker is defined as a device designed to open and close a circuit by non-auto-matic means and to open the circuit automatically on a predetermined overcurrent, without injury to itselfwhen properly applied within its rating.
ANSI definition-A circuit breaker is delined as a mechanical switching device, capable of making, carryingand breaking currents under normal circuit conditions and also making, carrying for a specilied time andbreaking currents under specified abnormal circuit conditions such as those of short circuit.
3.2 Circuit breakers in general
The premise is the same for both delinitions and both are accurate, but the wording is quite different. Thesame is true with the many types of circuit breakers. Their general purpose is the same, but there are also anumber of significant differences.
IEEE 1458-2005 pdf download
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