Siemens 5SU9356-2CN50 High Current Earth Leakage & Overcurrent RCBO 50A 30mA 1P+N D

The Siemens 5SU9356-2CN50 is a high-performance Residual Current Circuit Breaker with Overcurrent protection (RCBO), specifically engineered for robust earth leakage and overcurrent detection in demanding industrial environments. This 1-pole + neutral (1P+N) device boasts a substantial 50A rated current and a sensitive 30mA tripping current, offering critical safety and protection for electrical installations. Its advanced design ensures reliable operation, minimizing downtime and safeguarding personnel and equipment from hazardous electrical faults.

Product Specifications

| Feature                  | Specification                                     |

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

| Product Type             | RCBO (Residual Current Circuit Breaker with Overcurrent) |

| Manufacturer             | Siemens                                           |

| Model Number             | 5SU9356-2CN50                                     |

| Rated Current (In)       | 50 A                                              |

| Rated Residual Operating Current (IΔn) | 30 mA                                             |

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

| Breaking Capacity (Icn)  | 10 kA                                             |

| Tripping Characteristic  | Type D                                            |

| Voltage Rating           | 230/400 V AC                                      |

| Frequency                | 50/60 Hz                                          |

| Mounting Type            | DIN Rail                                          |

| Terminal Type            | Screw Terminal                                    |

| IP Protection Rating     | IP20 (Body), IP40 (Enclosure)                     |

| Operating Temperature    | -25°C to +55°C                                    |

Core Features & Market Positioning

The Siemens 5SU9356-2CN50 distinguishes itself through its integrated earth leakage and overcurrent protection, consolidating two essential safety functions into a single, compact unit. This simplifies panel design and installation, a key advantage in space-constrained industrial settings. The Type D tripping characteristic is particularly noteworthy, offering enhanced immunity to nuisance tripping caused by high inrush currents common in motor starting applications and inductive loads. This precise and reliable tripping mechanism, combined with a 50A capacity, positions the 5SU9356-2CN50 as a superior choice for critical power distribution circuits where both safety and operational continuity are paramount. Its robust construction and adherence to stringent international safety standards underscore Siemens' commitment to industrial-grade reliability and performance.

Key Application Scenarios

This RCBO is ideally suited for protecting circuits in a wide array of industrial applications where significant current loads and the potential for earth faults exist. Its 50A rating and Type D curve make it exceptionally effective for motor control circuits, power distribution panels in manufacturing plants, and heavy machinery operations. It is also a critical component for safeguarding equipment in facilities with large power supplies, such as data centers, substations, and industrial workshops, preventing electrical fires and protecting sensitive machinery from damage. Furthermore, its 30mA sensitivity ensures compliance with safety regulations for personnel protection against electric shock in areas with higher risk, such as those involving damp conditions or accessible conductive parts.

Practical System Integration Guidance

Integrating the Siemens 5SU9356-2CN50 into existing or new electrical systems is straightforward due to its standard DIN rail mounting and accessible screw terminals. Proper wiring is crucial: the line conductor should connect to the terminal marked "L" (or phase indicator) and the neutral conductor to the terminal marked "N". Ensure all connections are tight to prevent overheating and maintain reliable contact. When used for motor protection, it's vital to coordinate the RCBO's tripping characteristics with the motor's startup current requirements. For systems requiring multiple protection devices, consistent wiring practices and adherence to local electrical codes are essential for safe and compliant installation, ensuring that both earth leakage and overcurrent protection are fully functional.

Operation and Risk Mitigation

The primary function of the Siemens 5SU9356-2CN50 is to automatically disconnect the power supply when an earth fault current exceeding 30mA is detected, or when an overcurrent situation (short circuit or overload) occurs. This rapid tripping mechanism is vital for preventing electrical fires, equipment damage, and severe electric shock hazards. In the event of a fault, the device's toggle will move to the OFF position. To reset, ensure the fault condition has been rectified, then simply toggle the device back to the ON position. Regular testing of the earth leakage function using the integrated test button is recommended to ensure its continued operational integrity.

Scalability & Long-Term Value

The Siemens 5SU9356-2CN50 offers significant long-term value through its compatibility with Siemens' broader industrial control and automation portfolio. It can be seamlessly integrated into larger Siemens SIVACON systems or used in conjunction with other SENTRON protection devices, facilitating system expansion and upgrades. This ensures that as operational demands change or regulations evolve, the electrical infrastructure can be scaled without requiring a complete overhaul of protective devices. The inherent reliability and durability of Siemens products also contribute to reduced maintenance costs and extended operational life, offering a sound investment for critical industrial power protection.

Frequently Asked Questions

What is the primary function of the Siemens 5SU9356-2CN50?

This RCBO provides essential protection against earth leakage currents. It also offers crucial overcurrent protection against overloads and short circuits, ensuring electrical safety.

It is designed to prevent electrical fires and protect equipment from damage. The device automatically disconnects power when fault conditions are detected.

The Siemens 5SU9356-2CN50 combines two vital safety functions into one unit, simplifying installation and panel space. It is built for demanding industrial environments.

How does the 30mA tripping current benefit my system?

A 30mA residual operating current offers enhanced personnel protection against electric shock. This sensitivity is often a regulatory requirement in many industrial settings.

This level of sensitivity allows for the detection of smaller leakage currents that could indicate developing faults or pose a shock risk. It acts as a critical safety net.

By tripping at 30mA, the device minimizes the risk of serious injury or fatality from indirect contact with live parts. It is a key feature for safety compliance.

What does the "Type D" tripping characteristic mean for motor applications?

Type D offers a higher magnetic trip level, ideal for inductive loads with high inrush currents, like motors. It prevents nuisance tripping during startup.

This characteristic ensures that the RCBO does not unnecessarily disconnect power when a motor starts, maintaining operational continuity. It balances protection with usability.

For applications involving motors or transformers, a Type D RCBO like the 5SU9356-2CN50 is specifically engineered to handle these transient current demands. It is designed for robust performance.