LA High Magnetic Withstand Circuit Breaker The Power Solution for Mission Critical Loads

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1 Data Bulletin 0600DB0202 /2002 Cedar Rapids, IA, USA LA High Magnetic Withstand Circuit Breaker The Power Solution for Mission Critical Loads INTRODUCTION MODIFIED LA CIRCUIT BREAKER Mission critical loads within power systems are defined as zero downtime systems. Typical facilities requiring 24/7 power availability include: Computer Systems Banking and Financial Centers Data Centers Server Farms Data Banks Network and Telecommunication Systems These systems require a high level of selective coordination between the main and branch circuit breakers to provide maximum power system availability. Peak let-through currents of downstream branch circuit breakers are often high enough to engage the magnetic trip of larger main circuit breakers supplying power to additional branch circuits. The absence of selective coordination between molded case circuit breakers and branch circuit breakers means that the instantaneous trip elements within these circuit breakers overlap. Because of this, facilities can experience widespread disruption, costly downtime and potential business losses. Although this level of coordination is available today by using electronic trip circuit breakers with adjustable LSI functions, this option is usually cost prohibitive and may require additional space. The LA High Magnetic Withstand Circuit Breaker is designed to trip at a higher magnetic trip level. Typical Molded Case Circuit Breakers (MCCBs) and Molded Case Switches used in these applications will trip at 5 0 the handle rating. The LA High Magnetic Withstand Circuit Breaker utilizes higher magnetic trip levels and trips at 8 20 the handle rating. 400 A = 8 200, 225 and 250 A = 20 The LA high magnetic withstand circuit breaker allows the downstream branch circuit breaker which is upstream from the fault and nearest to the fault to clear the fault Schneider Electric All Rights Reserved

2 LA High Magnetic Withstand Circuit Breaker The Power Solution for Mission Critical Loads 0600DB0202 Data Bulletin /2002 Increased Selectivity Through higher magnetic tripping levels, the LA High Magnetic Withstand Circuit Breaker provides a higher degree of selectivity between itself and downstream branch circuit breakers. This ensures that only the upstream branch circuit breaker closest to the fault will trip. Figure : Simplified One-Line Diagram 208Y/20 V 3 Phase panel 250 A 3P LA High Mag Circuit Breaker Selective Coordination achieved at 8 20 LA circuit breaker handle rating. LA High Magnetic circuit breaker holds allowing QO circuit breaker to clear the downstream fault. FAULT QO 20 A P COMPUTER RACK QO 20 A P COMPUTER RACK Increased Performance Through Withstand Ratings The withstand rating validates the protection of the main circuit breaker and the cable. Proven Technology Frame Size The LA High Magnetic Withstand Circuit Breaker uses the same LA frame which has been available for many years with a proven track record for reliability. Accessories The LA High Magnetic Withstand Circuit Breaker uses all standard circuit breaker accessories. Connectors and Connections The LA High Magnetic Withstand Circuit Breaker has been designed to have the same available lug configurations as the current LA molded case circuit breaker family. This means that all connectors and existing catalog connections are available including I-LINE. Compliance with Standards UL 489 Listed CSA Certified Catalog Numbers Unit Mount Construction LAL34400MC 400 A LAL34250MC 250 A LAL34225MC 225 A LAL34200MC 200 A I-LINE Construction LA34400MC 400 A LA34250MC 250 A LA34225MC 225 A LA34200MC 200 A Schneider Electric All Rights Reserved

3 0600DB0202 LA High Magnetic Withstand Circuit Breaker The Power Solution for Mission Critical Loads /2002 Data Bulletin TRIP CURVES NOTE: The trip curves shown in this publication are for general reference only. For application and coordination purposes, contact Square D to obtain trip curves with the EZ-AMP overlay feature. Figure 2: 400 A LA High Magnetic Withstand Circuit Breaker 0000 CIRCUIT BREAKER INFORMATION 000 Circuit Breaker Continuous Maximum Number Prefix / Suffix Ampere Rating AC Voltage of Poles LA, LH / MC , TIME IN SECONDS. MAXIMUM CLEARING TIME (AT 50 Hz) (AT 60 Hz) CYCLE 2 CYCLE MULTIPLES OF RATED CURRENT 2002 Schneider Electric All Rights Reserved 3

4 LA High Magnetic Withstand Circuit Breaker The Power Solution for Mission Critical Loads 0600DB0202 Data Bulletin /2002 Figure 3: 250 A LA High Magnetic Withstand Circuit Breaker 0000 CIRCUIT BREAKER INFORMATION 000 Circuit Breaker Continuous Maximum Number Prefix / Suffix Ampere Rating AC Voltage of Poles LA, LH / MC , 3 00 TIME IN SECONDS 0. MAXIMUM CLEARING TIME (AT 50 Hz) (AT 60 Hz) CYCLE 2 CYCLE MULTIPLES OF RATED CURRENT Schneider Electric All Rights Reserved

5 0600DB0202 LA High Magnetic Withstand Circuit Breaker The Power Solution for Mission Critical Loads /2002 Data Bulletin Figure 4: 200/225 A LA High Magnetic Withstand Circuit Breaker 0000 CIRCUIT BREAKER INFORMATION 000 Circuit Breaker Continuous Maximum Number Prefix / Suffix Ampere Rating AC Voltage of Poles LA, LH / MC , 3 00 TIME IN SECONDS 0. MAXIMUM CLEARING TIME (AT 50 Hz) (AT 60 Hz) CYCLE 2 CYCLE MULTIPLES OF RATED CURRENT 2002 Schneider Electric All Rights Reserved 5

6 LA High Magnetic Withstand Circuit Breaker The Power Solution for Mission Critical Loads 0600DB0202 Data Bulletin /2002 Square D Company 3700 Sixth St SW Cedar Rapids, IA, USA -888-SquareD ( ) Electrical equipment should be installed, operated, serviced, and maintained only by qualified personnel. No responsibility is assumed by Schneider Electric for any consequences arising out of the use of this material Schneider Electric All Rights Reserved