ABB SACE SM3 630 630A PLC Switch: Communication-Enabled Moulded Case Circuit Breaker

The ABB SACE SM3 630 is a high-performance moulded case circuit breaker (MCCB) rated at 630A, designed for low-voltage distribution and motor protection. The “PLC Switch” designation refers to its ability to interface with programmable logic controllers via integrated communication modules. Part of the SACE SM3 series, this breaker combines robust short-circuit breaking capacity (up to 70kA at 415V) with electronic trip units that provide adjustable protection parameters and remote monitoring capabilities, making it suitable for modern smart power management systems.

Electrical Ratings and Breaking Capacity

The ABB SACE SM3 630 is available with three-pole (3P) or four-pole (4P) configurations. Rated insulation voltage (Ui) is 1000V AC, and rated impulse withstand voltage (Uimp) is 12kV. The ultimate short-circuit breaking capacity (Icu) is 70kA at 415V AC (50/60Hz), while the service breaking capacity (Ics) is 100% of Icu. The breaker is suitable for category A applications (non-selective) and can be used as a main switch or feeder protection. It complies with IEC 60947-2 and UL 489 standards.

PLC Integration and Communication Features

The “PLC Switch” capability is realized through optional communication modules that mount on the breaker. These modules support Modbus RTU, Profibus DP, or DeviceNet protocols, enabling direct connection to a PLC system. Parameters such as current, voltage, power, and trip status can be read remotely, while remote open/close commands can be issued via the motor operator accessory. The breaker also provides digital outputs for alarm and trip signals, which can be wired to PLC inputs for fast response. This integration allows centralized monitoring and control within industrial automation networks.

Protection Functions and Adjustability

Depending on the trip unit selected, the SACE SM3 630 offers: adjustable overload protection (L) with long-time delay, short-circuit protection (S) with fixed or adjustable delay, instantaneous protection (I), and ground fault protection (G) on electronic versions. The electronic PR331/P unit provides true RMS measurement, configurable protection curves, and energy metering functions. A local LCD display shows real-time values and trip history. The thermal-magnetic version provides fixed magnetic trip at 10x In and thermal adjustable from 0.7 to 1.0 In.

Mechanical and Environmental Specifications

The SACE SM3 630 features a compact moulded case made of glass-reinforced polyamide, with dimensions: 210mm (H) x 140mm (W) x 110mm (D) for 3-pole version. Terminal connections accept copper or aluminium cables up to 2x240mm². The breaker is rated for ambient temperature operation from -25°C to +70°C (derating above 50°C). It has a mechanical life of 20,000 operations and electrical life of 8,000 operations at rated current. IP20 protection is provided for the front panel when closed; optional IP40 with protective cover.

Typical Applications

This breaker is widely used in main distribution boards, motor control centers (MCCs), and PLC-controlled machinery panels. Its communication capability makes it ideal for applications requiring remote diagnostics, energy management, and predictive maintenance, such as data centers, industrial plants, and renewable energy systems. When paired with an ABB PLC or any third-party controller supporting Modbus, the SACE SM3 630 provides real-time circuit protection status and allows automated load shedding or resetting.

Installation and Accessories

Installation involves DIN rail or screw mounting (backplate). Standard accessories include: rotary handles (direct or extended), motor operator (24-240V AC/DC), shunt trip, undervoltage release, auxiliary contacts (1NO+1NC or 2NO+2NC), and terminal shields. For PLC integration, the communication module (type SACE PR120/K) is required, which connects via a ribbon cable to the electronic trip unit. ABB provides configuration software (Ekip Connect) for setting parameters via a laptop. The SACE SM3 630 is CE marked and RoHS compliant.