Applying Interrupting Rating: Circuit Breakers

PublishTime：2020-11-23

An overcurrent protective device must have an interrupting rating equal to or greater than the fault current available at its line terminals for both three-phase bolted faults and for one or more phase-to-ground faults (110.9). Although most electrical systems are designed with overcurrent devices having adequate three-phase interrupting ratings, the single-pole interrupting capabilities are easily overlooked. This section will examine single pole interrupting capability (also referred to as individual pole interrupting capability).
This section will show how single-pole interrupting capabilities must be considered in some applications. It will also show there are simple solutions that exist to provide adequate interrupting ratings if molded case circuit breakers, self protected starters and other overcurrent protective devices are found to have insufficient single-pole interrupting capabilities.
A Fine Print Note was added to 430.52(C)(6) of the 2005 NEC® and 240.85 of the 2002 NEC®. These Fine Print Notes alert users that mechanical devices,such as self-protected combination controllers and circuit breakers, have single-pole interrupting capabilities that must be considered for proper application.

Brand of Product：	Eaton Bussmann
Part#：
Product Category：	Circuit Breakers More
Application：	More
Data Type：	Supplier and Product Introduction More
Safety & Environment Standards：	More
Operating Temperature：	Please see the document for details
Qualification Grade：	More
Qualification Approval：	More
Package：
Language：	English Chinese Chinese and English Japanese
Date of Creation：	2019/05/28
Version Number：
Data Encoding：
Data Size：	820 KB

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