Siemens 5SU9356-8CN32 RCBO Earth Leakage Protection 32A 30mA 1P+N D

The Siemens 5SU9356-8CN32 RCBO is a high-performance residual current and overcurrent protection device designed for industrial and commercial applications. It offers robust protection with a 6 kA breaking capacity and a 32A current rating, coupled with a sensitive 30mA earth leakage trip for enhanced safety. The 1P+N (single pole plus neutral) configuration ensures efficient protection in single-phase systems. This RCBO is engineered for reliability, ease of integration, and compliance with stringent international safety standards, making it a preferred choice for protecting personnel and equipment from electrical hazards.

Product Specifications

| Parameter                        | Value                                       |

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

| Product Number                   | 5SU9356-8CN32                               |

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

| Poles                            | 1P+N (Single Pole + Neutral)                |

| Rated Current (In)               | 32A                                         |

| Rated Fault Current (IΔn)        | 30mA                                        |

| Rated Short-Circuit Breaking Capacity (Icn) | 6 kA                                        |

| Rated Voltage (Un AC)            | 230V / 240V                                 |

| Release Characteristic           | C (Typical for general circuits)            |

| Leakage Current Type             | AC (Type AC for sinusoidal AC residual currents) |

| Degree of Protection (IP)        | IP20                                        |

| Connection Type                  | Screw Terminals                             |

| Mounting                         | DIN Rail (35mm)                             |

| Width                            | 2 Modular Widths (approx. 36mm)             |

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

| Compliance Standards             | EN 61009-1, EN 61009-2-1, IEC 60947-2        |

| Country of Origin                | China (as per some listings, though Siemens products are manufactured globally) |

Core Features & Market Positioning

The Siemens 5SU9356-8CN32 RCBO stands out in the competitive landscape due to its robust construction and comprehensive protection capabilities. It consolidates the functions of an RCCB (Residual Current Circuit Breaker) and an MCB (Miniature Circuit Breaker) into a single, space-saving unit. This integration simplifies electrical panel designs and reduces installation time. The device is recognized for its reliability, a hallmark of the Siemens SENTRON protection device range, which is trusted in demanding industrial environments. Its Type AC design ensures effective protection against sinusoidal AC residual currents, making it suitable for a wide array of standard AC applications. The market positioning of this RCBO is as a dependable, efficient, and cost-effective solution for essential electrical safety, offering a balance between advanced features and value.

Key Application Scenarios

The Siemens 5SU9356-8CN32 RCBO is ideally suited for a variety of applications where combined overcurrent and earth leakage protection is critical. Common scenarios include:

  Residential Buildings: Protecting socket outlets and final circuits in homes, kitchens, bathrooms, and outdoor areas to prevent electric shock and fire hazards.  Commercial Installations: Safeguarding circuits in offices, retail spaces, and small businesses from overloads, short circuits, and dangerous earth faults.  Industrial Environments: Providing essential protection for machinery, control panels, and general power distribution in factories and workshops. The 6 kA breaking capacity is suitable for circuits with moderate fault current potential.  Infrastructure Projects: Used in applications such as lighting circuits, ventilation systems, and auxiliary power supplies where reliable protection is paramount.

Practical System Integration Guidance

Integrating the Siemens 5SU9356-8CN32 RCBO into existing or new electrical systems is straightforward, thanks to its standard DIN rail mounting and modular design.

  Wiring: The 1P+N configuration requires connecting the live conductor to the designated "L" terminal and the neutral conductor to the "N" terminal. The circuit's outgoing live and neutral conductors are then connected to the respective output terminals. Ensure all connections are tight to prevent overheating. The device typically accommodates conductor cross-sections suitable for 32A circuits, often ranging from 1.5 mm² to 6 mm² solid or stranded wire.  Busbar Systems: For efficient panel building, the 5SU9356-8CN32 can be easily connected to standard busbar systems, such as Siemens' own 5ST3 pin busbars, allowing for quick and organized connections with other modular devices.  System Upgrades: When retrofitting existing installations, the compact nature of the RCBO allows for easy replacement of separate MCBs and RCCBs, saving space and simplifying wiring. Always ensure the upstream protective device offers appropriate selectivity if required.

Operation and Risk Mitigation

The Siemens 5SU9356-8CN32 operates by continuously monitoring the balance of current flowing through the live and neutral conductors. If an imbalance occurs (indicating current leakage to earth), it trips and disconnects the circuit within milliseconds.

  Safety Features: The primary function is personnel protection against electric shock. The 30mA tripping sensitivity is designed to operate before a dangerous current can pass through the human body. It also provides protection against fire hazards caused by persistent earth faults.  Troubleshooting: If the RCBO trips, a visual indicator on the device usually shows the reason for the trip (e.g., residual current or overcurrent). To reset, ensure the fault condition is resolved, then lift the switch handle. If it trips again immediately, a persistent earth fault or a short circuit is likely present and requires further investigation by a qualified electrician.  Nuisance Tripping: While designed to minimize false trips, certain sensitive electronic loads or transient surges can occasionally cause nuisance tripping. The "anti-nuisance tripping version" feature helps mitigate this, but proper system design and load selection remain crucial.

Scalability & Long-Term Value

The Siemens 5SU9356-8CN32 RCBO offers significant long-term value and scalability within the Siemens SENTRON ecosystem.

  Compatibility: It is fully compatible with other Siemens SENTRON devices and modular system accessories, allowing for standardized panel construction and easy expansion.  System Integration: While this specific model is a Type AC device, Siemens offers other RCBO types (like Type A) in the SENTRON range for applications requiring detection of pulsating DC residual currents. This allows for a tiered approach to protection as system requirements evolve.  IIoT and Digitalization: Siemens is a leader in industrial digitalization. While this specific RCBO is a foundational safety device, it can be integrated into larger smart building or industrial control systems where monitoring and data logging are managed by higher-level intelligent devices or gateways. The availability of Data Matrix codes on Siemens devices facilitates quick access to technical data via online support apps, aiding in lifecycle management.

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Frequently Asked Questions (FAQs)

1. What is the primary function of the Siemens 5SU9356-8CN32 RCBO?

The Siemens 5SU9356-8CN32 RCBO serves a dual protective role. It acts as a residual current device (RCD) to detect earth leakages and prevent electric shock. Simultaneously, it functions as a miniature circuit breaker (MCB) to protect against overcurrents like overloads and short circuits. This combined functionality ensures comprehensive safety for both personnel and electrical installations.

2. What does "32A 30mA 1P+N Type AC" signify for this RCBO?

"32A" indicates the maximum continuous current the device can safely handle. "30mA" is the residual current sensitivity; it trips when a leakage current of 30 milliamperes or more is detected, crucial for personal protection. "1P+N" means it protects one live pole and the neutral conductor. "Type AC" signifies it's designed to detect sinusoidal AC residual currents.

3. Can the Siemens 5SU9356-8CN32 be used in all types of electrical systems?

This RCBO is designed for single-phase AC systems operating at 230/240V. It is compliant with international standards and permitted in many countries, provided national installation regulations are observed. However, it's crucial to verify compatibility with specific system voltages, frequencies, and fault current levels.

4. What is the difference between Type AC and Type A RCBOs?

Type AC RCBOs are sensitive to sinusoidal AC residual currents only. Type A RCBOs, however, offer broader protection by detecting both sinusoidal AC residual currents and pulsating DC residual currents that may occur with modern electronic devices. The 5SU9356-8CN32 is a Type AC device.

5. How does this RCBO protect against overloads and short circuits?

The overcurrent protection is managed by an integrated miniature circuit breaker (MCB) function. It employs a thermal tripping mechanism for overloads, which is slower, and a magnetic tripping mechanism for short circuits, which is instantaneous, providing rapid protection against damaging high currents.

6. Is the Siemens 5SU9356-8CN32 suitable for residential or industrial use?

This RCBO is versatile and suitable for both. Its 6 kA breaking capacity is adequate for many residential and commercial applications, as well as light to medium industrial settings. For very high fault current situations, higher breaking capacity devices might be required.

7. What is the installation process for this RCBO?

Installation involves snapping the RCBO onto a standard 35mm DIN rail within an electrical distribution board. It requires connecting the incoming live and neutral wires to the appropriate terminals and then connecting the outgoing circuit wires. Proper earthing of the distribution board is essential.

8. What does the "C" characteristic mean in relation to this RCBO?

The "C" characteristic (often implied or stated for models like 5SU1356-1KK32 and 5SU1356-6KK32) refers to the magnetic trip curve of the MCB function. A Type C breaker is designed to trip between 5 to 10 times its rated current, making it suitable for circuits with moderate inductive or capacitive loads that might experience temporary current surges during energization.

9. How can I reset the RCBO after it has tripped?

After a trip, first identify and rectify the cause (e.g., earth fault or overload). Then, simply flip the switch handle upwards to reset the device. If it trips again immediately, the fault condition persists and requires professional diagnosis.

10. What is the long-term value and compatibility of this Siemens RCBO?

The 5SU9356-8CN32 integrates into the broader Siemens SENTRON system, offering excellent compatibility with other Siemens protective devices and accessories. This ensures a standardized and scalable electrical infrastructure, providing reliable protection and supporting future system expansions or upgrades.