Siemens 3VL4740-2AA36-0AA0 Molded Case Circuit Breaker

The Siemens 3VL4740-2AA36-0AA0 is a high-performance molded case circuit breaker (MCCB) from the 3VL series. Designed for industrial power distribution and motor protection, this breaker provides reliable overcurrent and short-circuit protection. With a rated current of 400A and three poles, it is suitable for main switchboard and feeder applications.

Electrical Ratings

Rated operational voltage Ue: 690V AC (50/60 Hz). Rated insulation voltage Ui: 800V. Impulse withstand voltage Uimp: 8 kV. Breaking capacity Icu at 415V: 55 kA; at 690V: 20 kA. Rated short-time withstand current Icw: 5 kA for 1 second. The breaker is suitable for category B (selective) applications.

Trip Unit Specifications

This model is equipped with a thermal-magnetic trip unit (TM). The thermal overload protection is adjustable from 0.7 to 1.0 x In (280A to 400A). The magnetic short-circuit protection is fixed at 10 x In (4000A) or can be adjusted via dial (models with adjustable magnetic trip – check specific code). It includes a trip indicator window showing overload or short-circuit fault.

Mechanical Features

The breaker features rotary knob operation with ON/OFF positions and a visible contact status indicator. It has a padlockable handle in the OFF position (up to three 8mm padlocks). Terminals accept cables up to 240 mm² (copper or aluminum). The housing is made of thermoset material with arc-resistant chambers. Dimensions: 210 x 140 x 110 mm. Weight 3.5 kg.

Accessories and Compliance

Compatible accessories include auxiliary contacts (1NO+1NC or 2NO+2NC), shunt trip (24V, 110V, 230V), undervoltage release, and rotary handle extensions. The breaker meets IEC 60947-2 and UL 489 standards. It is CE marked and RoHS compliant. Operating temperature: -25°C to +70°C, without derating up to 55°C.

Installation and Mounting

The 3VL4740 breaker is designed for screw mounting on a backplate or DIN rail using an adapter. It can be installed in any orientation; however, derating may apply if mounted horizontally. Line and load connections are clearly labeled. IP20 protection degree on terminals when cover is closed.

Typical Applications

Used as incoming main breakers for industrial control panels, feeder protection in distribution boards, and branch circuit protection for heavy machinery. Also suitable for motor circuit protection when combined with a contactor and overload relay.

Conclusion

The Siemens 3VL4740-2AA36-0AA0 molded case circuit breaker offers robust 400A protection with high breaking capacity. Its thermal-magnetic trip unit, compact dimensions, and versatile accessories make it a reliable choice for power distribution systems.