Product Overview

The ABB SCYC55830 with part number 3AFE58063282 is a molded case circuit breaker from the ABB Tmax XT series. This device is designed for overcurrent protection in low-voltage power distribution systems up to 690V AC. The Tmax XT series represents ABBs latest generation of molded case circuit breakers, offering high performance, compact dimensions, and a wide range of accessories. The SCYC55830 features a thermal-magnetic trip unit that provides both overload protection (thermal element) and short-circuit protection (magnetic element). The current rating and trip settings are adjustable within the frame size, allowing the same breaker to be used for different applications. The SCYC55830 is suitable for main distribution switchboards, branch circuit protection, motor protection, and as a main disconnect for industrial control panels. The breaker is rated for operation in ambient temperatures from -25°C to +70°C and meets international standards for low-voltage switchgear.

Technical Specifications

Thermal-Magnetic Trip Unit

The SCYC55830 is equipped with a thermal-magnetic trip unit that provides two independent protection functions. The thermal trip element consists of a bimetallic strip that heats up when current flows through the breaker. Under overload conditions, the heat causes the bimetallic strip to bend, eventually tripping the breaker. The thermal element has an inverse time characteristic, meaning that the tripping time decreases as the current increases. This characteristic matches the heating curve of electrical conductors and equipment, providing proper overload protection. The thermal trip setting is adjustable, typically from 0.7 to 1.0 times the frame rating, allowing the breaker to be matched to the specific load current. The magnetic trip element consists of a solenoid coil that generates a magnetic field proportional to the current. Under short-circuit conditions, the high current generates sufficient magnetic force to instantly trip the breaker, regardless of the thermal element state. The magnetic trip threshold is either fixed or adjustable, typically set to 5 to 10 times the rated current. The instantaneous magnetic trip protects against severe short circuits that could cause catastrophic damage if not cleared quickly.

Interrupting Performance

The interrupting rating (Icu) of the SCYC55830 depends on the specific frame size and version. For typical Tmax XT breakers, the interrupting capacity ranges from 25 kA for smaller frames up to 100 kA for larger frames at 415V AC. This high interrupting rating allows the breaker to be used in applications with high available fault current, such as main service entrance equipment close to the utility transformer. The breaker is also rated for Ics (service short-circuit breaking capacity), which is typically 100 percent of Icu for Tmax XT breakers, meaning the breaker can clear a fault at its full interrupting rating and still be capable of normal operation afterwards. The breaker is tested according to IEC 60947-2, which includes rigorous testing for short-circuit making and breaking capacity, temperature rise, dielectric properties, and mechanical endurance.

Construction and Accessories

The SCYC55830 features a compact molded case design made of high-strength, arc-resistant thermoplastic. The breaker mechanism is of the quick-make, quick-break type, ensuring positive contact operation regardless of how slowly the handle is moved. The arc extinguishing system uses de-ionization plates to cool and extinguish the arc quickly, minimizing contact erosion and limiting let-through energy. The breaker is available with a wide range of accessories including auxiliary contacts (for remote status indication), shunt trips (for remote tripping), undervoltage releases (for automatic tripping on voltage loss), and motor operators (for remote switching). The breaker can also be equipped with terminal extensions, phase barriers, and lockout/tagout provisions. The accessories are field-installable, allowing the breaker to be configured for specific application requirements without factory modification.

Key Features and Benefits

Applications

The ABB SCYC55830 is used in low-voltage power distribution systems for overcurrent protection. Typical applications include main circuit breakers in service entrance equipment for industrial and commercial buildings, branch circuit protection for lighting, power, and appliance circuits, motor protection as a manual motor starter or as part of a combination starter, and as a main disconnect for control panels and machinery.

Installation and Selection

The SCYC55830 should be selected based on the system voltage, load current, and available fault current at the point of installation. The breaker's rated current (In) must be greater than or equal to the maximum continuous load current, and the interrupting rating (Icu) must exceed the calculated short-circuit current. The breaker can be mounted on a DIN rail using standard adapters or directly on a mounting plate using screws. Proper torque must be applied to the terminal connections to ensure reliable electrical contact without damaging the breaker. The breaker handle should be accessible for manual operation and must not be obstructed by other equipment. For safety, the breaker should be installed in an enclosure that provides appropriate protection against accidental contact with live parts.

Standards Compliance

The SCYC55830 complies with IEC 60947-2 (Low-voltage switchgear and controlgear - Part 2: Circuit-breakers). The breaker also meets UL 489 (Molded-Case Circuit Breakers, Molded-Case Switches, and Circuit-Breaker Enclosures) and CSA C22.2 No. 5 for North American applications. The breaker carries CE marking for the European market.