Siemens 5SU9356-1CN25 RCBO for Earth Leakage & Overload Protection 25A 30mA 1P+N C

The Siemens 5SU9356-1CN25 RCBO stands as a critical component for safeguarding electrical installations, offering simultaneous earth leakage and overload protection in a compact 1P+N configuration. Engineered for reliability and efficiency, this 25A, 30mA device integrates advanced tripping mechanisms to prevent electrical shocks and equipment damage. Its superior design ensures robust performance in demanding industrial and commercial environments, making it a preferred choice for professionals prioritizing safety and operational continuity.

Product Specifications

| Feature                 | Specification                       |

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

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

| Manufacturer            | Siemens                             |

| Model Number            | 5SU9356-1CN25                       |

| Rated Current           | 25A                                 |

| Residual Current Rating | 30mA                                |

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

| Tripping Curve          | Type C                              |

| Breaking Capacity       | 6kA                                 |

| Voltage Rating          | 230/400V                            |

| Frequency               | 50/60Hz                             |

| IP Protection           | IP20                                |

| Mounting Type           | DIN Rail                            |

Core Features & Market Positioning

The Siemens 5SU9356-1CN25 distinguishes itself through its high-performance dual protection capabilities, seamlessly combining residual current and overcurrent detection within a single unit. This integration minimizes panel space and simplifies wiring, offering a cost-effective and efficient solution for modern electrical systems. Its Type C tripping curve is optimized for inductive loads, providing enhanced protection against nuisance tripping while still offering rapid response to fault currents. Siemens' reputation for quality and durability further solidifies the 5SU9356-1CN25's market position as a reliable, long-term investment for critical infrastructure where safety and uninterrupted operation are paramount. This RCBO is designed to meet stringent international safety standards, ensuring compliance and peace of mind for installers and end-users alike.

Key Application Scenarios

This Siemens RCBO is ideally suited for a wide array of applications demanding robust electrical protection. In residential settings, it provides essential safety for circuits feeding high-demand appliances like ovens, washing machines, and air conditioning units, protecting occupants from electric shock hazards. For commercial buildings, it ensures the integrity of power distribution to critical areas such as server rooms, retail spaces, and office environments, preventing downtime due to overloads or earth faults. Industrial facilities benefit immensely from its application in machine control circuits, lighting systems, and power outlets, where consistent and safe power delivery is crucial for operational efficiency and personnel safety. Its suitability for both single-phase and phase-neutral protected circuits makes it a versatile component across diverse electrical distribution boards.

Practical System Integration Guidance

Integrating the Siemens 5SU9356-1CN25 RCBO into existing electrical systems is a straightforward process, owing to its standard DIN rail mounting and clear terminal markings. Installers must ensure the correct termination of line and neutral conductors to their designated terminals, respecting the device's 1P+N configuration. Proper grounding of the protected circuit to the main earth system is also a prerequisite for effective earth leakage protection. Before energizing the circuit, a thorough visual inspection and continuity test are recommended to verify correct wiring and prevent potential short circuits. For circuits with significant inrush currents, such as those feeding motors or transformers, selecting the appropriate Type C tripping characteristic of the 5SU9356-1CN25 is vital to prevent unwarranted tripping while maintaining essential protection. Always adhere to local electrical codes and regulations during installation.

Operation and Risk Mitigation

The Siemens 5SU9356-1CN25 RCBO operates by continuously monitoring the balance of current flowing through the live and neutral conductors of a circuit. If an imbalance occurs, indicating current is leaking to earth (e.g., through a fault or contact with a live part), the residual current detection mechanism triggers a rapid disconnection. Simultaneously, the overcurrent protection element, with its Type C tripping curve, safeguards against damage caused by excessive current due to overloads or short circuits. Risk mitigation is inherent in its dual-function design; by quickly isolating faulty circuits, it drastically reduces the probability of electrical fires, equipment destruction, and severe electric shock injuries. Regular testing of the RCBO's functionality using its integrated test button is crucial for ensuring its continued operational readiness and effectiveness in protecting both people and property.

Scalability & Long-Term Value

The Siemens 5SU9356-1CN25 RCBO is designed for seamless integration within Siemens' broader electrical distribution and automation platforms, offering excellent scalability for future expansions or upgrades. Its compatibility with standard modular distribution board systems ensures that it can be easily incorporated into new panel designs or retrofitted into existing installations without requiring specialized modifications. For facilities looking to embrace digital transformation, this RCBO can be part of a larger smart electrical infrastructure, contributing to overall system monitoring and data collection when integrated with compatible energy management systems. This forward-looking compatibility ensures that investments in Siemens protection devices maintain their value over the long term, supporting evolving operational demands and the increasing need for intelligent, connected electrical systems.

Frequently Asked Questions (FAQs)

What is the primary function of the Siemens 5SU9356-1CN25 RCBO?

It provides dual protection against earth leakage and overcurrent faults. This ensures safety by preventing electric shock and protecting equipment from damage.

This device combines two essential safety features in one compact unit. It offers both residual current detection for shock protection and overcurrent tripping for overload and short circuit protection.

Its application is vital for meeting stringent electrical safety regulations in various residential, commercial, and industrial settings.

Can the Siemens 5SU9356-1CN25 be used for single-phase and three-phase applications?

This specific model is designed for 1P+N applications. It protects single-phase circuits.

It is suitable for systems requiring protection for one live conductor and the neutral. It is not a three-phase device.

For three-phase protection, a different RCBO configuration, typically 3P+N or combinations of 1P+N units, would be necessary.

What does the "C" in the Type C tripping curve signify?

The Type C curve indicates its response to overcurrents. It is designed for circuits with moderate inductive loads.

This tripping characteristic allows for higher inrush currents without nuisance tripping. It is common for motor control or lighting circuits.

It offers a tripping range between 5 to 10 times the rated current, balancing sensitivity with protection for such loads.

How do I test the functionality of the Siemens 5SU9356-1CN25 RCBO?

Each RCBO is equipped with a test button, usually marked "T". Pressing this button simulates an earth fault.

When the test button is pressed, the RCBO should trip, disconnecting the power. This confirms the residual current detection is operational.

It is recommended to perform this test regularly, typically monthly, to ensure the device remains in good working order.

What is the breaking capacity of the Siemens 5SU9356-1CN25 RCBO?

The breaking capacity is 6kA. This indicates the maximum fault current it can safely interrupt.

This specification ensures the RCBO can handle short-circuit currents commonly found in residential and smaller commercial installations.

A higher breaking capacity provides greater protection against severe fault conditions, preventing damage to the device itself.

What is the rated residual current sensitivity (30mA) for?

The 30mA sensitivity is crucial for personal protection. It is the threshold for detecting dangerous earth leakage currents.

This level of sensitivity is effective in preventing electric shock by quickly disconnecting power if current bypasses the intended circuit.

It is typically used for socket outlets and circuits where direct contact with electrical equipment is more probable.

Is the Siemens 5SU9356-1CN25 compatible with standard distribution boards?

Yes, it is designed for standard DIN rail mounting. This ensures easy installation in most modular distribution boards.

Its compact modular design allows for straightforward integration and replacement within existing electrical panels.

Compatibility ensures flexibility in electrical system design and maintenance, reducing installation complexity.

What are the advantages of using an RCBO over separate RCD and MCB?

An RCBO combines both functions into a single device. This saves panel space and simplifies wiring.

It offers a more streamlined installation process compared to wiring a separate Residual Current Device (RCD) and Miniature Circuit Breaker (MCB).

This integrated approach can lead to cost savings in terms of both components and labor for electrical installations.

What is the operating voltage for the Siemens 5SU9356-1CN25?

The operating voltage rating is 230/400V. This covers typical single-phase and three-phase mains supplies.

For single-phase applications, it operates at 230V, common in most residential and commercial power systems.

The 400V rating is relevant for systems where it might be part of a larger three-phase distribution.

What IP rating does the Siemens 5SU9356-1CN25 have?

The device has an IP20 rating. This signifies protection against solid objects greater than 12.5mm.

It is protected against finger contact but is not designed for environments exposed to water or dust.

This IP rating is standard for indoor electrical enclosures and distribution boards.