Siemens 5SU9356-1KK50 Earth Leakage & Overcurrent Protector RCBO 50A 30mA 1P+N C

The Siemens 5SU9356-1KK50 is a high-performance Earth Leakage and Overcurrent Protector (RCBO) designed for robust electrical safety and reliable circuit protection in demanding industrial environments. This 50A, 30mA, 1P+N unit offers advanced tripping characteristics and compact design, making it an essential component for safeguarding personnel and equipment against electrical faults. Its key advantages lie in its integrated protection against residual currents, short circuits, and overloads, providing a comprehensive safety solution in a single device.

Product Specifications

| Feature                    | Specification                               |

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

| Product Type               | Earth Leakage & Overcurrent Protector (RCBO) |

| Manufacturer               | Siemens                                     |

| Model Number               | 5SU9356-1KK50                               |

| Rated Current (In)         | 50A                                         |

| Residual Current (IΔn)     | 30mA                                        |

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

| Breaking Capacity (Icn)    | 6 kA                                        |

| Tripping Characteristic    | Type C                                      |

| Voltage Rating             | 230/400V AC                                 |

| Frequency                  | 50/60 Hz                                    |

| Mounting Type              | DIN Rail                                    |

| IP Protection Rating       | IP20                                        |

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

| Compliance Standards       | IEC/EN 61009-1                              |

Core Features & Market Positioning

The Siemens 5SU9356-1KK50 distinguishes itself through its Type C tripping characteristic, which provides enhanced protection against inrush currents commonly found in inductive loads, such as motors and transformers. This capability minimizes nuisance tripping while ensuring prompt disconnection under fault conditions, a critical advantage in industrial automation and machinery applications. Its compact 1P+N design saves valuable panel space, allowing for denser and more efficient electrical installations. Positioned as a premium safety device, it aligns with Siemens' reputation for reliability, advanced technology, and adherence to stringent international safety standards, offering peace of mind for critical infrastructure.

Key Application Scenarios

This RCBO is ideally suited for protecting individual circuits in industrial control panels, motor starter circuits, and distribution boards where both earth leakage and overcurrent protection are mandated. Common applications include protecting equipment in manufacturing plants, pump stations, HVAC systems, and any scenario involving potential residual currents from machinery or insulation degradation. Its 50A rating makes it suitable for circuits powering moderately to heavily loaded industrial equipment. The 30mA sensitivity is a standard for personal protection, preventing electric shock hazards in areas with increased risk.

Practical System Integration Guidance

Integrating the Siemens 5SU9356-1KK50 is straightforward, utilizing standard DIN rail mounting for quick installation in electrical enclosures. Wiring involves connecting the line conductor to the appropriate terminal and the neutral conductor to its designated terminal. The load conductors are then connected to the output terminals. Ensure all connections are torqued to the manufacturer's specifications to prevent overheating and ensure reliable operation. For systems requiring multiple RCBOs, maintain adequate spacing between units to allow for heat dissipation, especially in densely populated panels.

Operation and Risk Mitigation

The RCBO operates by continuously monitoring the current flowing through the live and neutral conductors. If an imbalance (indicating a residual current) exceeds 30mA, or if the current exceeds the rated 50A due to an overload or short circuit, the device will trip, rapidly disconnecting the power supply. This mechanism is crucial for preventing electrical fires, equipment damage, and electric shock. In the event of a trip, identify the cause of the fault before resetting the device. Common issues include insulation faults, faulty appliances, or wiring problems. Always disconnect power from upstream before attempting any troubleshooting or reset procedures.

Scalability & Long-Term Value

The Siemens 5SU9356-1KK50 is designed for integration within broader Siemens electrical systems and adheres to universal IEC standards, ensuring compatibility with a wide range of switchgear and components. While this specific unit offers a fixed set of protection parameters, scalability within an installation is achieved through the strategic use of multiple RCBOs for individual circuit protection. Its robust construction and Siemens' commitment to quality ensure long-term reliability and minimal maintenance requirements, contributing to the overall operational efficiency and safety of an electrical installation.

Frequently Asked Questions

1. What is the primary function of the Siemens 5SU9356-1KK50 RCBO?

It provides combined protection against earth leakage, overcurrents, and short circuits. This ensures both personal safety and equipment protection.

This RCBO is a vital safety device for preventing electric shock and electrical fires. It offers comprehensive circuit safeguarding in one unit.

The device disconnects power when fault currents exceed safe operational limits, ensuring reliable electrical system safety.

2. How does the 30mA sensitivity benefit industrial applications?

The 30mA sensitivity is critical for detecting small residual currents that could cause electric shock. This offers a high level of personnel protection.

It helps in complying with safety regulations that mandate protection against dangerous touch voltages in workplaces.

Detecting these subtle currents also aids in identifying early-stage insulation degradation, preventing more serious faults.

3. What type of loads is the 'C' curve characteristic suitable for?

The Type C curve is designed to handle moderate inrush currents from inductive loads. This includes motors and transformers.

It minimizes nuisance tripping caused by the temporary high currents drawn when certain equipment starts up.

This characteristic ensures reliable circuit protection without unnecessary interruptions in industrial settings.

4. Can the Siemens 5SU9356-1KK50 be used in residential buildings?

While technically capable, its 50A rating and industrial focus may be overkill for typical residential circuits. Residential RCBOs often have lower current ratings.

However, it can be used in specific areas of a home requiring higher current protection or where industrial-grade safety is desired.

For standard home circuits, a lower amperage RCBO with a Type B or Type A curve might be more appropriate and cost-effective.

5. What is the breaking capacity (Icn) of this RCBO and why is it important?

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

A higher breaking capacity ensures the RCBO can safely handle potential fault conditions without being destroyed.

It's vital to select an RCBO with a breaking capacity that meets or exceeds the prospective short-circuit current at the installation point.

6. How do I reset the Siemens 5SU9356-1KK50 after a trip?

First, identify and rectify the cause of the trip to prevent immediate re-tripping. This could be an overload or fault.

Ensure the main power to the circuit is stable and then firmly push the toggle switch to the "ON" position.

If the RCBO trips again immediately, a serious fault may exist, and an electrician should be consulted.

7. What does "1P+N" signify for this RCBO?

"1P+N" means the RCBO protects one live (phase) conductor and the neutral conductor. It switches both simultaneously.

This ensures complete isolation of the circuit from the power supply when a trip occurs, enhancing safety.

It's commonly used in single-phase systems where the neutral conductor also needs to be disconnected for safety reasons.

8. What are the environmental conditions suitable for operating this device?

This RCBO is designed for operation in ambient temperatures ranging from -25°C to +45°C.

It is important to ensure the installation environment does not exceed these temperature limits for optimal performance and longevity.

The IP20 rating indicates it is protected against solid objects larger than 12.5mm but offers no protection against water ingress.

9. How does this RCBO differ from a standard Miniature Circuit Breaker (MCB)?

An MCB only provides overcurrent and short-circuit protection. It does not offer earth leakage protection.

An RCBO combines the functions of an MCB with that of a Residual Current Device (RCD). It protects against earth faults and electric shock.

The added earth leakage detection capability makes RCBOs a more comprehensive safety solution for many applications.

10. Is the Siemens 5SU9356-1KK50 compatible with other Siemens industrial components?

Yes, it is designed to be fully compatible with other Siemens circuit breakers, busbars, and control gear within their industrial product portfolio.

Its standard DIN rail mounting and IEC compliance ensure interoperability with a vast range of electrical equipment from various manufacturers.

When building or expanding a Siemens electrical installation, this RCBO integrates seamlessly into existing systems.