Siemens 5SU9356-1KK32 Standard Current Integrated Protection RCBO 32A 30mA 1P+N C

The Siemens 5SU9356-1KK32 RCBO stands as a critical component in modern electrical protection, offering a robust solution for safeguarding circuits against overcurrent and earth leakage faults. This 32A, 30mA, 1P+N C-curve device integrates residual current and overcurrent protection into a single, compact unit, simplifying installations and enhancing safety. Its key advantages include space-saving design, reliable tripping performance, and compliance with stringent international standards. The core features emphasize its dual-functionality, ensuring both personal protection from electric shock and equipment protection from short circuits and overloads.

Product Specifications

| Feature                       | Specification                                      |

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

| Product Type                  | Residual Current Circuit Breaker with Overcurrent |

| Model Number                  | 5SU9356-1KK32                                      |

| Rated Current (In)            | 32 A                                               |

| Rated Residual Operating Current | 30 mA                                              |

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

| Tripping Characteristic       | C-Curve                                            |

| Rated Breaking Capacity (Icn) | 10 kA                                              |

| Rated Voltage (Ue)            | 230/400 V                                          |

| Frequency                     | 50/60 Hz                                           |

| Mounting Type                 | DIN Rail                                           |

| Degree of Protection          | IP20                                               |

| Ambient Temperature Range     | -25 to +45 °C                                      |

Core Features & Market Positioning

The Siemens 5SU9356-1KK32 RCBO is strategically positioned as a high-reliability, space-efficient protective device for commercial and residential electrical installations. Its integrated design significantly reduces panel size and wiring complexity compared to separate RCDs and MCBs, offering a cost-effective solution. The C-curve tripping characteristic is optimized for inductive loads, providing reliable protection without nuisance tripping. Siemens' reputation for quality and adherence to global safety standards (e.g., IEC/EN 61009-1) further solidifies its market standing, making it a preferred choice for specifiers and installers demanding dependable performance.

Key Application Scenarios

This Siemens RCBO is ideally suited for protecting circuits in various environments, including residential apartments, commercial buildings, and light industrial applications. Its primary role is to protect socket outlets and lighting circuits from overload and short circuits, while simultaneously providing essential personal protection against electric shock. It is particularly valuable in areas with higher risk of earth faults, such as kitchens, bathrooms, and outdoor installations, where a 30mA residual current rating offers crucial safety. The 32A rating makes it suitable for circuits supplying a moderate to high electrical load.

Practical System Integration Guidance

Integrating the Siemens 5SU9356-1KK32 RCBO onto a standard DIN rail is a straightforward process. Ensure the main power supply is de-energized before commencing any work. Connect the incoming live and neutral conductors to the designated terminals at the top of the device, observing correct polarity. The outgoing load conductors are then connected to the corresponding terminals at the bottom. For 1P+N configurations, both the live and neutral conductors of the circuit being protected must be routed through the RCBO. Proper grounding of the protected circuit to the main earthing system is essential for the residual current protection to function effectively.

Operation and Risk Mitigation

The Siemens 5SU9356-1KK32 operates by continuously monitoring the current flowing through the live and neutral conductors. If an imbalance is detected – indicating current leakage to earth (e.g., due to faulty insulation or accidental contact) – exceeding the 30mA threshold, the RCBO will rapidly trip, interrupting the circuit. The C-curve characteristic means it will trip on currents between 5 and 10 times its rated current (32A), suitable for loads with moderate inrush currents. Regular testing using the integrated test button is crucial to verify the functionality of the residual current sensing mechanism, typically recommended monthly. Failure to trip during a test indicates a fault requiring immediate attention.

Scalability & Long-Term Value

While the 5SU9356-1KK32 is a standalone protection device, its integration into Siemens' broader electrical distribution portfolio offers long-term value. It is compatible with other Siemens circuit protection devices and busbar systems, allowing for straightforward expansion or modification of electrical panels. For enhanced digital integration, while this specific model does not feature built-in communication, it can be part of a system that includes smart meters or intelligent distribution boards, enabling remote monitoring and data logging of circuit status and energy consumption through compatible gateways and software platforms. This ensures future-proofing for evolving smart building and industrial control requirements.

Frequently Asked Questions

What is the tripping current for the Siemens 5SU9356-1KK32?

The residual operating current that triggers the device is 30mA. This sensitivity is crucial for personal protection against electric shock.

The C-curve characteristic indicates it will trip for overcurrents between 5 to 10 times the rated current. This means for the 32A rating, tripping will occur between 160A and 320A for overloads.

The device also provides overcurrent protection for short circuits up to its breaking capacity of 10 kA, safeguarding against severe fault conditions.

How do I install the Siemens 5SU9356-1KK32 RCBO?

Ensure the electrical power is completely shut off before installation. Mount the RCBO securely onto a standard 35mm DIN rail within the distribution board.

Connect the incoming live and neutral wires from the power source to the upper terminals of the RCBO. Correct polarity is essential for proper operation.

Connect the outgoing live and neutral wires of the protected circuit to the lower terminals of the RCBO. Ensure all connections are tight and secure.

What type of loads can be protected by the Siemens 5SU9356-1KK32?

This RCBO is suitable for protecting circuits with moderate inductive inrush currents due to its C-curve tripping characteristic. It protects against overload and short circuits.

The 30mA residual current sensitivity provides vital protection against indirect contact (electric shock) for personnel. This makes it ideal for areas like bathrooms and kitchens.

Common applications include protection for socket outlets, lighting circuits, and general-purpose circuits in residential, commercial, and light industrial settings.

Is the Siemens 5SU9356-1KK32 suitable for industrial use?

Yes, it is well-suited for light industrial applications requiring reliable protection against earth faults and overcurrents. Its robust construction and 10kA breaking capacity are key features.

The C-curve is beneficial for machinery with moderate start-up currents, preventing nuisance tripping while still offering safety. It ensures operational continuity for essential equipment.

For heavy industrial applications with higher fault currents or specific tripping requirements, higher rated RCBOs or specialized industrial circuit breakers might be necessary.

What does 1P+N mean for this RCBO?

"1P+N" signifies that the device protects one live pole and the neutral conductor simultaneously. It is a single-pole device that includes switching for the neutral line.

This integrated switching of both live and neutral ensures complete isolation of the circuit during fault conditions or for maintenance purposes. It is essential for safety in many modern electrical systems.

Unlike a 1-pole device which only switches the live conductor, the 1P+N configuration offers enhanced safety by breaking both conductors, preventing potential shock hazards through the neutral.

How often should I test the Siemens 5SU9356-1KK32?

It is recommended to test the residual current function of the RCBO at least once a month. This ensures the earth leakage protection is operational.

Use the built-in test button located on the front of the device to perform the test. Pressing this button simulates an earth fault and should cause the RCBO to trip.

If the RCBO does not trip when the test button is pressed, it indicates a malfunction. The device should be immediately inspected and replaced by a qualified electrician.

What is the difference between an RCBO and an RCD?

An RCD (Residual Current Device) primarily provides protection against earth leakage faults, preventing electric shock. It does not protect against overcurrents or short circuits.

An RCBO (Residual Current Circuit Breaker with Overcurrent protection) combines the functions of an RCD and an MCB (Miniature Circuit Breaker). It protects against both earth leakage and overcurrent/short circuits.

Therefore, an RCBO offers comprehensive protection in a single device, whereas an RCD needs to be paired with an MCB for full circuit protection.

Can I use the Siemens 5SU9356-1KK32 for DC circuits?

No, the Siemens 5SU9356-1KK32 is designed and certified for use in AC (Alternating Current) circuits only. Using it on DC circuits can lead to unpredictable behavior and safety hazards.

It is specifically designed to detect imbalances in AC current flow, which is characteristic of earth leakage faults in AC systems. DC systems have different fault characteristics and require specialized DC protection devices.

Always ensure that the type of protection device used is appropriate for the type of current (AC or DC) and voltage of the circuit being protected.

What is the breaking capacity of the Siemens 5SU9356-1KK32?

The rated breaking capacity (Icn) of the Siemens 5SU9356-1KK32 is 10 kA (kiloamperes). This indicates the maximum fault current the device can safely interrupt without being damaged.

This 10kA rating is sufficient for most standard residential and commercial installations where the prospective fault current is unlikely to exceed this level. It ensures the device will reliably clear short circuits.

In industrial settings where higher fault currents might occur, a higher breaking capacity device might be required, often in conjunction with upstream protective devices to limit the fault current seen by the RCBO.

What does the C-curve mean on this RCBO?

The C-curve tripping characteristic signifies that the RCBO will trip when the current reaches a level between 5 to 10 times its rated current. For this 32A device, this range is approximately 160A to 320A.

This characteristic is designed for circuits that may experience moderate inrush currents when electrical equipment is switched on, such as motors or transformers. It prevents nuisance tripping during normal operation.

It offers a balance between sensitivity for protection and immunity to transient overcurrents, making it suitable for a wide range of applications where inductive loads are present.