Siemens 3VA1120-5MH32-0AA0 3VA11 Series Molded Case Air Circuit Breaker 20A 160A 3P 55kA

The Siemens 3VA1120-5MH32-0AA0 is a robust 3-pole molded case air circuit breaker from the 3VA11 series, engineered for reliable protection in demanding industrial environments. This 20A breaker boasts a significant breaking capacity of 55kA, making it suitable for circuits requiring high fault current interruption. Its compact design and advanced thermal-magnetic trip unit offer precise overcurrent protection, ensuring operational continuity and safeguarding equipment. The 3VA11 series is designed for seamless integration into various electrical distribution systems, providing dependable performance and enhanced safety.

Product Specifications

| Specification                 | Value                                      |

| :---------------------------- | :----------------------------------------- |

| Product Number                | 3VA1120-5MH32-0AA0                         |

| Series                        | 3VA11                                      |

| Number of Poles               | 3P                                         |

| Rated Current (Ie)            | 20 A (Adjustable from 16A to 20A)          |

| Maximum Breaking Capacity (Icu) | 55 kA at 400/415 V AC                      |

| Rated Voltage (Ue)            | Up to 600 V AC                             |

| Trip Unit Type                | Thermal-Magnetic (TM)                      |

| Adjustable Thermal Setting    | Yes                                        |

| Adjustable Magnetic Setting   | Yes                                        |

| Mounting Type                 | Fixed, Plug-in, Drawer versions available |

| Connection Type               | Screw terminals                            |

| Standards                     | IEC 60947-2, UL 489                        |

| Protection Degree             | IP20 (enclosure)                           |

Core Features & Market Positioning

The Siemens 3VA1120-5MH32-0AA0 distinguishes itself through its exceptional breaking capacity of 55kA, a critical feature for applications exposed to significant short-circuit currents. This high performance, combined with a reliable thermal-magnetic trip system, positions it as a competitive choice for robust power distribution and motor protection. The breaker's modular design facilitates easy customization with auxiliary and signaling switches, enhancing its adaptability for sophisticated control and monitoring systems. Its compliance with IEC and UL standards underscores its suitability for global markets and diverse project requirements.

Key Application Scenarios

This Siemens molded case circuit breaker is ideally suited for main and branch circuit protection in industrial plants, commercial buildings, and utility substations. Its 55kA breaking capacity makes it particularly effective in areas with high fault current potential, such as near transformers or generators. Common applications include protecting switchboards, motor control centers (MCCs), and individual power circuits for machinery and equipment. The adjustable thermal and magnetic settings allow for precise coordination with other protective devices, optimizing selectivity and minimizing nuisance tripping.

Practical System Integration Guidance

Installing the Siemens 3VA1120-5MH32-0AA0 involves securely mounting the breaker to a suitable busbar system or panel. Ensure adequate clearance around the unit for ventilation and accessibility. Terminations should be made using appropriately sized lugs, tightened to the specified torque values to ensure a reliable electrical connection and prevent overheating. For systems requiring remote signaling or control, auxiliary and signaling switches can be easily fitted to the side of the breaker, connecting to the control circuits as per the wiring diagrams provided in the product manual.

Operation and Risk Mitigation

Operating the 3VA1120-5MH32-0AA0 is straightforward, with a clear lever mechanism for switching between ON, OFF, and TRIP states. The thermal-magnetic trip unit offers adjustable settings for overload (thermal) and short-circuit (magnetic) protection, allowing for precise system coordination and preventing damage to downstream equipment. To mitigate risks, always ensure the breaker is properly rated for the circuit's current and voltage, and that the breaking capacity is sufficient for potential fault levels. Regular visual inspections and functional testing are recommended to maintain optimal performance and safety.

Scalability & Long-Term Value

The 3VA11 series offers a degree of scalability through its compatibility with various accessories, including auxiliary contacts, signaling contacts, and shunt releases, enabling integration into advanced automation and monitoring systems. While the 3VA1120-5MH32-0AA0 itself is a fixed configuration, Siemens' broader 3VA molded case circuit breaker platform provides a consistent design language and performance characteristics across different frame sizes, facilitating future upgrades or expansions within a facility's electrical infrastructure. Its robust construction and adherence to international standards ensure long-term reliability and reduced lifecycle costs.

FAQs

What is the rated current of the Siemens 3VA1120-5MH32-0AA0?

The Siemens 3VA1120-5MH32-0AA0 molded case circuit breaker has a rated current (Ie) of 20 Amperes. This rating is often adjustable within a certain range, typically from 16A to 20A on this specific model, allowing for precise setting.

This adjustable feature is crucial for fine-tuning protection levels according to specific load requirements. Proper setting ensures optimal device performance and prevents unnecessary tripping or under-protection.

Users can typically adjust the thermal setting via a dial located on the front of the breaker. The magnetic setting can also often be adjusted, providing flexibility in trip characteristics.

What is the breaking capacity of the 3VA1120-5MH32-0AA0?

This Siemens circuit breaker features a substantial breaking capacity (Icu) of 55 kA at 400/415 V AC. This high rating is essential for safely interrupting severe short-circuit currents.

A 55kA breaking capacity signifies the maximum fault current the breaker can interrupt without sustaining damage. This ensures system safety during extreme electrical events.

Applications in areas with high fault current potential, such as near power sources or large transformers, benefit significantly from this high-capacity protection. It ensures reliable disconnection and prevents cascading failures.

How is the Siemens 3VA1120-5MH32-0AA0 installed?

Installation involves securely mounting the fixed-type breaker onto a suitable electrical panel or busbar system. Proper torque must be applied to the terminal connections for electrical integrity.

Ensure that the breaker is correctly rated for the circuit's voltage and intended current. Adequate ventilation space around the unit is also critical for preventing overheating.

Consult the official Siemens installation manual for detailed instructions and torque specifications. Incorrect installation can compromise safety and performance.