Siemens 5SN6625-7CN MCB for Transformer Protection 3P+N 25A

The Siemens 5SN6625-7CN MCB is a high-performance miniature circuit breaker engineered for robust transformer protection. This 3-pole + neutral device, rated at 25A, offers superior tripping characteristics and enhanced safety for electrical distribution systems. Its key advantages include reliable fault current interruption, precise overcurrent and short-circuit protection, and compact design for efficient panel space utilization. Critical technical parameters include a rated breaking capacity of 6kA, C-curve tripping characteristic, and adherence to IEC 60898-1 and IEC 60947-2 standards, ensuring compliance and dependable operation in demanding industrial environments.

Siemens 5SN6625-7CN: Specifications and Performance

| Parameter                     | Specification                     |

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

| Product Type                  | Miniature Circuit Breaker (MCB)   |

| Manufacturer                  | Siemens                             |

| Model Number                  | 5SN6625-7CN                       |

| Poles                         | 3P+N (3 Pole + Neutral)           |

| Rated Current (In)            | 25A                               |

| Rated Breaking Capacity (Icn) | 6kA                               |

| Tripping Characteristic       | C-Curve                           |

| Voltage Rating (Ue)           | 400V AC                           |

| Frequency                     | 50/60 Hz                          |

| Compliance Standards          | IEC 60898-1, IEC 60947-2          |

| Protection Type               | Overcurrent, Short-Circuit        |

| Terminal Type                 | Screw Terminal                    |

| Installation Type             | DIN Rail Mount                    |

Core Features and Market Positioning

The Siemens 5SN6625-7CN MCB distinguishes itself through its advanced C-curve tripping characteristic, which provides optimal protection for inductive loads like transformers. This specific curve ensures that the breaker tolerates temporary inrush currents common during transformer energization without nuisance tripping, while still offering rapid and reliable disconnection during harmful short circuits. Its robust construction and adherence to stringent international standards position it as a reliable and compliant solution for critical infrastructure and industrial applications where equipment longevity and operational safety are paramount. Unlike some general-purpose MCBs, the 5SN6625-7CN is specifically designed for transformer protection, offering a tailored performance profile that minimizes downtime and protects valuable assets.

Key Application Scenarios

This Siemens 5SN6625-7CN MCB is ideally suited for protecting small to medium-sized transformers in various industrial settings, including manufacturing plants, process control systems, and commercial buildings. It serves as a crucial component in distribution boards and control panels where safeguarding transformer windings from overloads and short-circuit faults is essential to prevent costly damage and operational disruptions. Its 3-pole + neutral configuration is particularly beneficial for systems requiring complete isolation of all active conductors and the neutral line, enhancing overall system safety during maintenance or fault conditions. The 25A rating makes it a versatile choice for a range of transformer sizes commonly encountered in these applications.

Practical System Integration Guidance

Integrating the Siemens 5SN6625-7CN MCB into existing electrical systems is straightforward due to its standard DIN rail mounting and screw terminal connections. Ensure that the incoming power supply from the transformer and the outgoing load wiring are correctly terminated at the respective terminals, paying close attention to polarity if applicable. For 3-phase transformer applications, connect the three line conductors to terminals L1, L2, and L3, and the neutral conductor to the designated neutral terminal. It is crucial to verify that the ambient temperature and environmental conditions where the MCB is installed are within the manufacturer's specified operating range to ensure optimal performance and longevity. Always consult the full installation manual for detailed wiring diagrams and safety precautions.

Operation and Risk Mitigation

The Siemens 5SN6625-7CN MCB operates automatically, interrupting the circuit when the current exceeds its calibrated threshold due to an overload or a short circuit. The C-curve characteristic ensures a trip within 5 to 10 times the rated current, balancing sensitivity to faults with tolerance for inrush currents. To mitigate risks, always ensure the MCB is correctly rated for the transformer's full load current and potential inrush. Regular visual inspections for any signs of damage or overheating, along with periodic testing of its tripping function, are recommended. Never attempt to reset a tripped breaker without first identifying and rectifying the underlying cause of the fault.

Scalability & Long-Term Value

While the Siemens 5SN6625-7CN MCB itself is a fixed-rating device, its value lies in its compatibility with Siemens' broader range of industrial control and protection equipment. This allows for seamless integration into larger, scalable power distribution architectures. It can be part of a system that evolves to incorporate smart metering, remote monitoring, or advanced automation, contributing to the development of more intelligent and connected industrial facilities. Its durable construction and reliable performance contribute to long-term operational value by minimizing maintenance needs and protecting critical transformer assets from premature failure.

Frequently Asked Questions

What is the tripping characteristic of the Siemens 5SN6625-7CN MCB?

The Siemens 5SN6625-7CN MCB features a C-curve tripping characteristic. This curve is designed to handle moderate inrush currents. It provides reliable protection against short circuits.

What is the rated breaking capacity of this MCB?

This MCB has a rated breaking capacity of 6kA. This means it can safely interrupt fault currents up to 6000 Amperes. It is suitable for many industrial and commercial power distribution systems.

Can the Siemens 5SN6625-7CN be used for phase-to-phase faults?

Yes, the 3-pole + neutral configuration provides protection for all three phases. It will interrupt phase-to-phase and phase-to-neutral faults. Ensure correct wiring for comprehensive protection.

What types of transformers can this MCB protect?

This 25A MCB is suitable for smaller to medium-sized transformers. It is ideal for inductive loads with specific inrush current requirements. Always verify the transformer's rated current.

How does the C-curve benefit transformer protection?

The C-curve allows for higher inrush currents during transformer energization. It prevents nuisance tripping from temporary surges. Yet, it trips quickly on sustained short circuits.

What are the main advantages of using a Siemens MCB for transformer protection?

Siemens MCBs offer high reliability and safety. They are built to stringent international standards. This ensures dependable operation and asset protection.

What is the voltage rating for this specific MCB?

The Siemens 5SN6625-7CN MCB is rated for 400V AC. This voltage is common in European and many international industrial power systems. Always match the MCB voltage to the system voltage.

Is this MCB suitable for residential or only industrial use?

This MCB is specifically designed for industrial and commercial applications. Its robust features and transformer protection capabilities are tailored for these environments. It meets industrial safety standards.

What does 3P+N signify in the product name?

3P+N indicates that the circuit breaker has three poles for the live conductors and a dedicated pole for the neutral conductor. This provides complete protection for systems where the neutral is switched.

What safety precautions should be taken during installation?

Always de-energize the system before installation. Verify correct wiring and terminal connections. Ensure the MCB is properly mounted on a DIN rail. Consult the manufacturer's manual for detailed safety guidelines.