Siemens developed highly flexible molded-case circuit breaker (MCCB) frame sizes for high-current applications to address the needs of switchgear manufacturers and panel builders in environments characterized by increasing complexity, digitalization, and cost pressures. The new 3VA UL Large Frame MCCBs enable users to implement powerful, safe, and smart systems while allowing them to improve and greatly simplify their work processes. The 1,200- and 1,600-A frame sizes meet the requirements of IEC and UL standards. This is particularly advantageous for manufacturers who are producing systems destined for global markets. The new 2,000-A frame is designed exclusively for the UL market. The new frame sizes will be available in both thermal-magnetic and electronic-trip unit versions. Molded case switch (MCS) variants will also be offered.

The primary responsibility of MCCBs is to protect personnel and equipment against electrical damage and failures. The integrated arc energy reduction feature (Dynamic Arc Flash Sentry, DAS+) ensures the 3VA UL Large Frame MCCBs trip rapidly in the event of a fault during work being carried out in the immediate vicinity of live parts. In this way, the arc energy and, thus, the energy released in the power distribution equipment room is reduced. This technology is in compliance with the National Electric Code (NEC) for the U.S. market and was designed to protect service technicians from serious injury resulting from arc flash hazards.
The 3VA UL Large Frame electronic-trip units (ETUs) offer fully integrated communication and measurement features. Energy and circuit breaker data is recorded with an accuracy of +/-1% and transmitted to higher-level systems. This functionality is integrated into the ETUs and no longer requires additional accessories to be mounted in the circuit breaker. In addition, all 3VA MCCB frame sizes (125 to 2,000 A) use common internal accessories. This allows for flexible functional adjustments, lowers inventory levels, simplifies planning and selection, and reduces overall time and costs.

Other highlighted features include:

  • Common internal accessories with the existing 3VA MCCB portfolio (alarm switches, auxiliary switches, shunt trips, undervoltage releases, etc.).  
  • Extensive suite of external accessories, including connection technology, mounting bases, external circuit breaker operators, interlocks, and test devices.  
  • UL 100% ratings available in 1.200- and 1.600-A frame sizes for thermal-magnetic trip unit (TMTU) and ETU circuit breakers. 
  • DAS+ arc energy reduction as a standard feature in all ETU versions — U.S. NEC compliant.  
  • Circuit breakers equipped with ETU and LCD display are communication-ready; additional communication modules are not required. 
  • The mechanical platform is based on the predecessor 3VL design. As a result, the footprint is nearly identical to the 3VL7 (NG) and 3VL8 (PG) MCCBs, allowing for a simple upgrade to 3VA molded-case circuit breakers in existing switchgears.