IEEE 1458-2005 pdf free.IEE E Recommended Practice for the Selection, Field Testing, and Life Expectancy of Molded Case Circuit Breakers for Industrial Applications.
IEEE 1458 provides a recommended procedure for the selection, application, and determination of the remaining life in molded case circuit breakers. This recommended procedure is safe and easily understood.
1.2 Purpose
Molded case circuit breakers arc one of the most widely used circuit protection devices in low-voltage (less than 1000 volt) applications. In spite of their wide use in industry, the average person specifying, installing, operating and maintaining these devices has less than a complete understanding of them. The purpose of this document is to provide people who purchase or maintain molded case circuit breakers with a single document that includes the Ihllowing inthrmation:
How molded case circuit breakers operate
Flow to correctly size and select molded case circuit breakers
I-low 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 documents arc indispensable for the application of this standard. For dated references, only the edition cited applies. For undated re1rences, the latest edition of the retrenced document (including any amendments or corrigenda) applies.
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 things in common and an even larger number of dissimilar features and capabilities. The main groupings selected to cover circuit breakers are listed here as an introduction, without defining or explaining the individual groupings 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 ckflnirion—A circuit breaker is defined as a device designed to open and close a circuit by non-automatic means and to open the circuit automatically on a predetermined overcurrent, without injury to itself when properly applied within its rating.
ANSI definuson—A circuit breaker is defined as a mechanical switching device, capable of making, carrying and breaking currents under normal circuit conditions and also making, carrying for a specified time and breaking currents under specified abnormal circuit conditions such as those of short circuit.IEEE 1458 pdf free download.