Siemens 5SN6550-7CN Miniature Circuit Breaker 1P+N 50A

The Siemens 5SN6550-7CN is a robust 1-pole + neutral miniature circuit breaker (MCB) rated at 50A, engineered for reliable overcurrent protection in diverse electrical installations. This MCB distinguishes itself through its high breaking capacity, ensuring safety during fault conditions, and its compact design, facilitating space-efficient panel building. Its advanced tripping characteristics provide precise protection against both overload and short-circuit events, safeguarding sensitive equipment and preventing downtime. Designed for AC applications, the 5SN6550-7CN is a cornerstone component for modern electrical distribution systems, offering dependable performance and adherence to stringent international safety standards.

| Feature                 | Specification                             |

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

| Product Type            | Miniature Circuit Breaker (MCB)           |

| Manufacturer            | Siemens                                   |

| Model Number            | 5SN6550-7CN                               |

| Number of Poles         | 1P+N (1 Pole + Neutral)                   |

| Rated Current (In)      | 50A                                       |

| Rated Voltage (Ue)      | 230/400V AC (dependent on configuration)  |

| Tripping Characteristic | Type C (typical for inductive loads)      |

| Breaking Capacity (Icn) | 6 kA (at 400V AC)                         |

| Frequency               | 50/60 Hz                                  |

| Insulation Voltage (Ui) | 500V                                      |

| Protection Degree       | IP20 (terminal area)                      |

| Mounting Type           | DIN Rail (35mm)                           |

| Operating Temperature   | -25°C to +45°C                            |

Core Features & Market Positioning

The Siemens 5SN6550-7CN leverages Siemens' extensive experience in circuit protection, positioning itself as a dependable and cost-effective solution for residential, commercial, and light industrial applications. Its Type C tripping curve is particularly advantageous for installations with moderate inrush currents, such as those containing fluorescent lighting or small motors. The inclusion of a neutral pole in a single unit simplifies wiring and reduces overall component count, a significant advantage in terms of installation time and cost. Compared to alternatives, the 5SN6550-7CN offers a superior balance of performance, reliability, and brand trust, backed by Siemens' global reputation for quality in electrical engineering.

Key Application Scenarios

This 50A MCB is ideally suited for main distribution boards and sub-distribution panels where comprehensive protection of circuits with moderate to high load currents is required. Common applications include protecting circuits supplying power to heating systems, air conditioning units, electric water heaters, and machinery in workshops or small manufacturing facilities. Its 1P+N configuration makes it particularly relevant for single-phase installations where neutral conductor switching is mandated or beneficial for enhanced safety. The robust 6 kA breaking capacity ensures it can safely interrupt fault currents in typical building installations, providing essential protection for downstream wiring and connected appliances.

Practical System Integration Guidance

Integrating the Siemens 5SN6550-7CN into existing or new electrical systems is straightforward due to its standard 35mm DIN rail mounting. Ensure the incoming phase and neutral conductors are connected to the corresponding line terminals (usually at the top), and the outgoing load conductors are connected to the load terminals (usually at the bottom). Correct polarity is crucial for proper operation. Always verify that the connected load does not exceed the MCB's rated current of 50A. For systems requiring multiple MCBs, ensure adequate spacing for ventilation within the enclosure. Wiring should be performed by a qualified electrician in accordance with local electrical codes and standards.

Operation and Risk Mitigation

The Siemens 5SN6550-7CN operates by automatically interrupting the circuit when an overcurrent (overload or short circuit) is detected, indicated by the tripping of the toggle lever to the "OFF" position. To reset the breaker after a fault, ensure the fault condition has been cleared, then firmly push the toggle lever to the "ON" position. If the breaker repeatedly trips, it indicates a persistent overcurrent issue or a fault within the protected circuit that requires professional diagnosis. Never attempt to reset a breaker that trips immediately or repeatedly without identifying and rectifying the underlying cause. Ensure the MCB is rated for the specific voltage and frequency of the installation to prevent premature failure or hazardous conditions.

Scalability & Long-Term Value

As part of the broader Siemens system portfolio, the 5SN6550-7CN offers excellent compatibility with other Siemens switchgear and distribution components, facilitating the creation of scalable and integrated electrical systems. While this specific model is designed for direct circuit protection, its reliable performance contributes to the long-term value of an installation by minimizing the risk of equipment damage and electrical fires. For enhanced monitoring or integration into smart building systems, consider pairing it with Siemens' range of residual current devices (RCDs) and surge protection devices, or exploring more advanced solutions within Siemens' digital power distribution offerings for IIoT connectivity.

Frequently Asked Questions

What is the breaking capacity of the Siemens 5SN6550-7CN?

The Siemens 5SN6550-7CN boasts a breaking capacity of 6 kA at 400V AC. This ensures it can safely interrupt significant fault currents.

This high breaking capacity is critical for preventing catastrophic damage during short circuits. It protects downstream equipment and wiring from severe electrical stress.

Installers must ensure this rating is sufficient for their specific installation's potential fault levels according to local codes.

How do I correctly install the Siemens 5SN6550-7CN MCB?

Mount the MCB onto a standard 35mm DIN rail within your electrical enclosure. Connect the incoming live and neutral wires to the designated line terminals.

Ensure all connections are tight and secure. Connect the outgoing load wires to the corresponding load terminals. Follow all local electrical codes for proper wiring.

Always ensure the power is completely isolated before beginning any installation work. Verify the MCB's rating matches the circuit's expected load.

What type of loads is the Siemens 5SN6550-7CN MCB suitable for?

This MCB features a Type C tripping characteristic, making it ideal for loads with moderate inrush currents. Examples include fluorescent lighting and small motors.

It offers reliable protection against overloads and short circuits for general-purpose circuits. It's well-suited for residential and commercial electrical distribution.

Avoid using this MCB for high inrush current loads like large motors or transformers, which may require a Type D characteristic.

Can the Siemens 5SN6550-7CN be used in DC circuits?

The Siemens 5SN6550-7CN is designed and rated for AC (Alternating Current) circuits only. Its tripping mechanisms are optimized for AC fault conditions.

Using this MCB in a DC circuit can lead to unreliable performance and potential safety hazards. DC circuits have different arc-quenching requirements.

Always ensure the circuit breaker's AC rating matches the application. For DC applications, specific DC circuit breakers must be used.

What does 1P+N mean for this Siemens MCB?

1P+N signifies that the circuit breaker has one pole for the live conductor and a separate pole for the neutral conductor. Both are switched simultaneously.

This 1P+N configuration allows for complete isolation of the live and neutral lines from the circuit. It offers enhanced safety compared to single-pole breakers that only switch the live wire.

It is commonly used in single-phase installations where switching the neutral conductor is required by electrical codes or for added safety.

How do I reset the Siemens 5SN6550-7CN after a trip?

After a trip, ensure the fault condition has been identified and rectified. Then, firmly push the toggle lever all the way up to the "ON" position.

If the MCB trips again immediately, do not force it. This indicates the fault persists and requires professional investigation by an electrician.

Repeatedly resetting a faulty breaker can be dangerous and may damage the breaker or the protected equipment. Always address the root cause.

What are the dimensions and mounting requirements for this MCB?

The Siemens 5SN6550-7CN is designed for standard 35mm top-hat DIN rail mounting. Its compact dimensions facilitate installation in standard distribution boards.

Ensure there is adequate space within the enclosure for proper ventilation around the MCB. This helps maintain optimal operating temperature.

Consult the product's datasheet for precise physical dimensions if panel layout is critical for space planning.

What is the tripping characteristic (e.g., Type C) and why is it important?

The Type C characteristic means the MCB will trip between 5 to 10 times its rated current for short circuits. This provides a balance for common loads.

Type C is suitable for most domestic and commercial applications with moderate inductive loads, like fluorescent lights or small motors. It avoids nuisance tripping.

For loads with very high inrush currents, such as large motors or transformers, a Type D breaker might be necessary to prevent premature tripping.

Where is the Siemens 5SN6550-7CN typically used in an electrical installation?

This MCB is commonly found in main distribution panels and sub-distribution boards for protecting individual circuits. It’s used in residential, commercial, and light industrial settings.

Applications include protecting circuits for appliances, lighting, sockets, and smaller machinery. Its 50A rating suits higher current single-phase loads.

It serves as a vital safety device, safeguarding wiring and connected equipment from overloads and dangerous short circuits.

What safety precautions should be taken when working with this MCB?

Always ensure the main power supply to the distribution board is switched OFF and locked out before any work. Use appropriate Personal Protective Equipment (PPE).

Verify that the MCB's electrical ratings (voltage, current) are compatible with the circuit it is protecting. Never bypass or tamper with the MCB's internal mechanisms.

Only qualified electricians should perform installation, maintenance, or troubleshooting on electrical panels containing MCBs.