Siemens 5SU9356-8CN50 RCBO with Earth Leakage & Overcurrent Protection 50A 30mA 1P+N D

The Siemens 5SU9356-8CN50 RCBO offers robust, integrated protection for electrical circuits, combining residual current and overcurrent safeguarding in a single, compact unit. This device is engineered for superior reliability and enhanced safety, featuring a 50A rated current and a 30mA sensitivity for effective earth leakage detection. Its 1P+N configuration simplifies installation and reduces panel space, making it an ideal solution for demanding industrial and commercial applications. The Type D tripping characteristic ensures it can handle high inrush currents, crucial for protecting equipment with inductive loads.

Product Specifications

| Feature                  | Specification                       |

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

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

| Manufacturer             | Siemens                             |

| Model Number             | 5SU9356-8CN50                       |

| Rated Current (In)       | 50A                                 |

| Residual Current (IΔn)   | 30mA                                |

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

| Tripping Characteristic  | Type D                              |

| Breaking Capacity (Icn)  | 10kA                                |

| Voltage Rating (Ue)      | 230/400V AC                         |

| Frequency                | 50/60Hz                             |

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

| Protection Type          | Overcurrent, Short Circuit, Earth Leakage |

| Mounting Type            | DIN Rail                            |

| Compliance Standards     | IEC/EN 61009-1, IEC/EN 60898-1      |

Core Features & Market Positioning

The Siemens 5SU9356-8CN50 stands out in the market due to its all-in-one protection capabilities, significantly streamlining electrical panel design and installation. Its Type D curve is a key differentiator, providing essential overcurrent protection for circuits with high starting currents, such as those powering motors, transformers, or heavy machinery, without nuisance tripping. This robust design ensures operational continuity while maintaining stringent safety standards. The 30mA residual current sensitivity is optimal for personal protection against electric shock in various environments. Siemens' reputation for quality and reliability further cements the 5SU9356-8CN50's position as a preferred choice for critical infrastructure and industrial automation projects.

Key Application Scenarios

This RCBO is extensively deployed in industrial facilities to protect motor control circuits, power distribution boards, and machinery feeds, where inductive loads are common. It is also a critical component in commercial building electrical systems, safeguarding circuits that supply lighting, HVAC systems, and sensitive electronic equipment from both overloads and dangerous earth faults. Furthermore, the 5SU9356-8CN50 is suitable for use in areas requiring enhanced safety measures, such as workshops, laboratories, and data centers, providing comprehensive protection against electrical hazards.

Practical System Integration Guidance

Integrating the Siemens 5SU9356-8CN50 RCBO into existing or new electrical systems is straightforward due to its standard DIN rail mounting and compact 1P+N design. Proper wiring involves connecting the line conductor to the designated input terminal and the neutral conductor to its corresponding input terminal. The load conductors are then connected to the output terminals. It is imperative to ensure that the incoming power supply is de-energized before commencing any installation work. System designers must verify that the RCBO's rated current (50A) and breaking capacity (10kA) are appropriately matched to the circuit's expected fault levels and load demands to guarantee effective protection.

Operation and Risk Mitigation

The Siemens 5SU9356-8CN50 operates by continuously monitoring the current flowing through the live and neutral conductors. If an imbalance is detected, indicating current leakage to earth, or if the current exceeds the overcurrent protection threshold, the RCBO will rapidly trip, disconnecting the power supply. This action prevents electrical fires, equipment damage, and electric shock. Regular testing of the residual current function using the integrated test button (typically marked 'T') is crucial for ensuring operational readiness. In the event of a persistent tripping issue, a thorough inspection of the circuit for earth faults or overloads is recommended, and professional electrical expertise should be sought if problems persist.

Scalability & Long-Term Value

The 5SU9356-8CN50 RCBO integrates seamlessly within Siemens' broader industrial control and automation platforms, such as the SENTRON system. This compatibility ensures that it can be part of a scalable electrical infrastructure, allowing for future expansions or upgrades to more sophisticated protection and monitoring systems. Its robust construction and adherence to international standards like IEC/EN 61009-1 contribute to its long service life and reduce the total cost of ownership. For facilities adopting IIoT and smart grid technologies, this RCBO serves as a foundational element for enhanced safety and operational intelligence within the power distribution network.

FAQs

What is the primary function of a Siemens 5SU9356-8CN50 RCBO?

This device integrates residual current detection with overcurrent protection. It safeguards circuits from earth leakages, preventing electric shock and fires. It also protects against overloads and short circuits, preventing equipment damage.

It offers a combined safety solution, reducing the need for separate RCDs and MCBs. The 50A rating and 30mA sensitivity are key parameters for its protective capabilities.

This RCBO ensures electrical safety and operational reliability in a single, compact unit. Its Type D characteristic is vital for specific industrial applications.

How does the Type D tripping characteristic benefit industrial applications?

Type D breakers are designed for circuits with high inrush currents. This makes them ideal for protecting equipment like motors, transformers, and lighting transformers.

These devices prevent nuisance tripping during normal startup surges. This ensures uninterrupted operation of critical industrial machinery.

Without a Type D curve, sensitive equipment could be repeatedly disconnected during normal operation. This leads to production downtime and potential equipment damage.

What are the key technical specifications of the Siemens 5SU9356-8CN50?

It features a 50A rated current and 30mA residual current sensitivity. The unit is a 1-pole + neutral device (1P+N).

This RCBO has a breaking capacity of 10kA and operates on a 230/400V AC supply. It is designed for 50/60Hz frequency.

The device is compliant with IEC/EN 61009-1 and IEC/EN 60898-1 standards. It mounts on a standard DIN rail for easy installation.

What types of circuits is the Siemens 5SU9356-8CN50 suitable for?

It is highly suitable for industrial circuits powering inductive loads. This includes motor circuits and machinery feeds with high starting currents.

In commercial settings, it protects circuits for HVAC, lighting, and sensitive electronic equipment. It provides crucial earth leakage protection.

The 30mA sensitivity is ideal for personal protection applications. It ensures safety in environments where accidental contact with live parts is possible.

Can this RCBO be used for personal protection?

Yes, with a 30mA residual current sensitivity, it is classified for personal protection. This level is effective in detecting dangerous earth faults.

It helps prevent electric shock hazards for individuals interacting with electrical equipment. Its rapid tripping minimizes the duration of current flow.

This makes it a vital safety component in residential, commercial, and industrial settings for safeguarding personnel.

What does '1P+N' configuration mean for this RCBO?

'1P+N' signifies that the RCBO protects one live pole and switches the neutral conductor simultaneously. It occupies a single modular width in a distribution board.

This configuration is common for single-phase circuits in many electrical installations. It simplifies wiring and saves space compared to separate pole and neutral devices.

It ensures that both the live and neutral conductors are disconnected during a fault. This enhances overall circuit isolation and safety.

How do I test the residual current function of the 5SU9356-8CN50?

Locate the test button, usually marked with a 'T', on the front of the RCBO. Ensure the circuit is energized and the RCBO is in the ON position.

Press the test button firmly. The RCBO should immediately trip, indicating the residual current detection mechanism is functioning correctly.

If the RCBO does not trip, do not assume it is faulty. Test again after ensuring correct installation and power supply. If it still fails, professional inspection is required.

What are the implications of the 10kA breaking capacity?

A 10kA breaking capacity means the RCBO can safely interrupt fault currents up to 10,000 Amperes. This rating is crucial for circuit safety.

It ensures the device can withstand and safely clear severe short circuits without damage. This prevents cascading failures in the electrical system.

The breaking capacity must be selected based on the prospective short-circuit current at the point of installation. Using an undersized breaker is a serious safety hazard.

Is the Siemens 5SU9356-8CN50 compatible with existing Siemens electrical panels?

Yes, the 5SU9356-8CN50 is part of the Siemens SENTRON protection device series. It is designed for seamless integration.

It adheres to standard DIN rail mounting and dimensions, ensuring compatibility with most Siemens distribution boards and enclosures. This facilitates easy retrofitting or new installations.

Its modular design aligns with Siemens' broader electrical system architecture, supporting scalability and future upgrades.

What environmental conditions should be considered for installing this RCBO?

The RCBO is rated for operation between -25°C and +45°C. It should be installed within this temperature range for optimal performance.

Avoid areas with excessive moisture, dust, or corrosive atmospheres unless appropriate enclosures are used. Proper ventilation is also important to prevent overheating.

Consider local electrical codes and regulations regarding installation environments for protective devices. Consult the product manual for specific environmental ratings.