Siemens 5SU1356-1KK32 Residual Current Earth Leakage Protection Switch 32A 30mA 1P+N C

The Siemens 5SU1356-1KK32 is a high-performance Residual Current Earth Leakage Protection Switch designed for robust electrical safety in demanding industrial and commercial environments. This 32A, 30mA, 1-pole + neutral (1P+N) device offers superior protection against electric shock, fire hazards caused by earth faults, and overcurrents, ensuring operational continuity and personnel safety. Its advanced tripping characteristics and compact design make it an ideal choice for modern electrical installations requiring reliability and compliance with stringent safety standards.

Product Specifications

| Feature                 | Specification                                         |

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

| Product Type            | Residual Current Earth Leakage Protection Switch      |

| Model Number            | 5SU1356-1KK32                                         |

| Rated Current (In)      | 32A                                                   |

| Rated Residual Current  | 30mA                                                  |

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

| Tripping Characteristic | Type C (for inductive loads, higher inrush currents)  |

| Breaking Capacity (Icn) | 6kA                                                   |

| Voltage Rating          | 230V                                                  |

| Frequency               | 50/60 Hz                                              |

| Terminal Type           | Screw Terminals                                       |

| Mounting Type           | DIN Rail (35mm)                                       |

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

| Protection Class        | IP20 (device), IP40 (enclosure)                       |

| Standards Compliance    | IEC/EN 61009-1, IEC/EN 61009-2-1, IEC/EN 60898-1       |

Core Features & Market Positioning

The Siemens 5SU1356-1KK32 distinguishes itself through its precise and reliable earth leakage detection, crucial for preventing severe electrical hazards. Its Type C tripping curve offers enhanced protection for circuits with higher inrush currents, common in industrial motor applications and lighting systems, preventing nuisance tripping while maintaining safety. This robust construction and adherence to international standards like IEC/EN 61009-1 position it as a premium safety component for professionals prioritizing dependable protection and system integrity. The 6kA breaking capacity ensures it can safely interrupt fault currents, further bolstering its reliability in challenging environments.

Key Application Scenarios

This residual current switch is paramount in protecting single-phase circuits in a variety of settings. It is widely deployed in industrial facilities for safeguarding machinery and control panels, ensuring operator safety and preventing costly downtime due to earth faults. In commercial buildings, it is essential for circuits powering sensitive electronic equipment, server rooms, and retail spaces where fire prevention is critical. Residential applications also benefit significantly, particularly in areas with higher risk, such as kitchens, bathrooms, and outdoor electrical installations, providing a vital layer of defense against electric shock for occupants.

Practical System Integration Guidance

Integrating the Siemens 5SU1356-1KK32 into existing electrical panels is straightforward due to its standard 35mm DIN rail mounting. Ensure the incoming live and neutral conductors are connected to the designated line terminals (usually marked L and N), and the outgoing protected conductors are connected to the load terminals. The neutral conductor must be connected through the switch. Proper grounding of the system is essential for the residual current device to function effectively. Always disconnect power to the circuit before performing any installation or wiring work, and adhere to local electrical codes and regulations. The device is designed for simple plug-and-play integration within standard distribution boards.

Operation and Risk Mitigation

The 5SU1356-1KK32 operates by continuously monitoring the balance of current flowing through the live and neutral conductors of a circuit. If an imbalance exceeding 30mA is detected, indicating current is leaking to earth (potentially through a person or faulty equipment), the switch rapidly disconnects the power supply within milliseconds. This swift action significantly mitigates the risk of electric shock and prevents the ignition of fires due to persistent earth faults. Regular testing using the integrated test button (typically marked 'T') is crucial to ensure the device remains operational and responsive to fault conditions.

Scalability & Long-Term Value

While the 5SU1356-1KK32 is a single-pole + neutral device, its compatibility with the broader Siemens industrial electrical product ecosystem offers long-term value. It seamlessly integrates with other Siemens circuit breakers, RCDs, and distribution board components, allowing for flexible system design and future expansion. Its robust build quality and reliable performance ensure a long service life, minimizing the need for premature replacement. For projects requiring higher levels of protection or different configurations, Siemens offers a comprehensive range of residual current devices that can be specified to meet evolving project demands.

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Frequently Asked Questions

1. What is the primary function of the Siemens 5SU1356-1KK32?

This device acts as a crucial safety component in electrical systems. It is designed to detect and interrupt circuits when an earth leakage current exceeds a safe threshold, preventing electric shock. Its 30mA sensitivity is ideal for personal protection against direct contact.

The switch also provides protection against indirect contact, ensuring that fault currents do not pose a fire risk. It combines residual current detection with overcurrent protection, offering a dual-functionality for enhanced safety and system reliability.

By rapidly disconnecting power during a fault, it minimizes potential damage to equipment and prevents hazardous situations from escalating. This makes it an indispensable part of modern electrical installations where safety is paramount.

2. Can the Siemens 5SU1356-1KK32 be used for 3-phase applications?

No, the Siemens 5SU1356-1KK32 is specifically a 1-pole + neutral (1P+N) device. It is designed for use in single-phase AC circuits only. Using it in a 3-phase system would be incorrect and unsafe.

For 3-phase applications, you would require a different type of residual current device, such as a 4-pole RCD or an appropriate combination of single-pole RCDs depending on the system configuration and protection requirements. It is vital to select the correct device for the specific electrical system.

Always consult the product datasheet and relevant electrical standards to ensure the appropriate residual current protection device is chosen for the intended application. Proper selection is key to effective electrical safety.

3. What does "32A 30mA" signify in the product name?

The "32A" indicates the rated operational current of the switch, meaning it can safely handle a continuous load of up to 32 amperes. This is the maximum current the device can conduct under normal operating conditions.

The "30mA" refers to the rated residual current. This is the minimum earth leakage current that will cause the switch to trip and disconnect the power supply. A 30mA sensitivity is generally considered sufficient for protecting persons from dangerous electric shocks.

Together, these specifications mean the Siemens 5SU1356-1KK32 protects circuits up to 32A against overcurrents and provides high-level personal protection against earth leakage faults with a 30mA tripping threshold.

4. How is the Type C tripping characteristic beneficial?

A Type C tripping characteristic means the circuit breaker portion of the switch is designed to withstand higher inrush currents without tripping. This is particularly useful for inductive loads like motors, transformers, and fluorescent lighting ballasts.

These types of loads can draw a significantly higher current for a brief moment when they are first switched on compared to their normal operating current. A Type C curve allows for these temporary surges.

By accommodating these inrush currents, the Type C characteristic prevents nuisance tripping of the protective device, ensuring the reliable operation of equipment while still providing essential protection against sustained overcurrents and earth faults.

5. What is the installation process for this residual current switch?

Installation involves mounting the switch onto a standard 35mm DIN rail within an electrical distribution board or enclosure. Power must be completely disconnected before commencing any work.

The live (L) and neutral (N) conductors from the power source are connected to the "line" or input terminals. The protected live and neutral conductors supplying the load are then connected to the corresponding "load" or output terminals.

It is crucial to ensure correct polarity and secure all connections. After wiring, the test button should be pressed to verify proper function before re-energizing the circuit. Always follow local electrical codes and regulations.

6. How often should the test button on the 5SU1356-1KK32 be used?

The test button should be operated regularly, typically on a monthly basis, to ensure the internal tripping mechanism of the residual current switch is functioning correctly. This is a critical maintenance step for any RCD.

Pressing the test button simulates an earth fault condition, causing the switch to trip and disconnect the circuit. If the switch does not trip, it indicates a fault with the device, and it should be replaced immediately by a qualified electrician.

This simple periodic test is a vital safety measure that helps confirm the device's readiness to protect against real earth leakage faults, providing peace of mind and ensuring continued safety for the connected circuit.

7. What is the breaking capacity of this Siemens switch?

The Siemens 5SU1356-1KK32 has a breaking capacity of 6kA (kiloamperes). This specification indicates the maximum fault current the switch can safely interrupt without sustaining damage to itself or the electrical system.

A 6kA breaking capacity is suitable for most standard residential, commercial, and light industrial applications where the prospective fault current is not excessively high. It ensures that the device can effectively clear dangerous fault currents.

Choosing a residual current switch with an adequate breaking capacity for the installation's fault current level is essential for ensuring safety and preventing catastrophic failures during short-circuit events.

8. Does this product offer protection against overvoltage?

No, the Siemens 5SU1356-1KK32 is primarily designed for residual current protection (earth leakage) and overcurrent protection (short circuit and overload). It does not provide direct protection against overvoltage surges.

For protection against transient overvoltages, such as those caused by lightning strikes or switching surges, a separate surge protective device (SPD) would need to be installed in conjunction with this switch. SPDs are designed to divert excess voltage safely to earth.

It's important to understand the specific protective functions of each electrical component. Combining RCDs with SPDs and appropriate circuit breakers creates a comprehensive protection strategy for electrical installations.

9. What standards does the 5SU1356-1KK32 comply with?

The Siemens 5SU1356-1KK32 complies with several key international and European standards for electrical safety devices. These include IEC/EN 61009-1 and IEC/EN 61009-2-1, which specifically cover residual current operated protective devices incorporating overcurrent protection.

It also meets the requirements of IEC/EN 60898-1, a standard for electrical accessories such as circuit breakers for household and similar installations. Compliance with these standards ensures the product has been rigorously tested for performance, safety, and reliability.

Adherence to these recognized standards signifies that the 5SU1356-1KK32 meets the high levels of protection expected in industrial, commercial, and residential electrical systems globally.

10. How does this device integrate with Siemens IIoT or digital solutions?

The 5SU1356-1KK32 is a foundational safety device, and while it doesn't have direct digital communication capabilities itself, it integrates into broader Siemens industrial automation and IIoT platforms through compatible distribution boards and intelligent meters.

Siemens offers connected solutions where devices like this RCD can be monitored indirectly via smart meters or communication gateways installed in the same distribution system. This allows for remote status checking and fault notification.

For advanced digital integration and monitoring of electrical parameters, including leakage currents, Siemens provides specific intelligent devices and software platforms within their SENTRON or MindSphere ecosystems. This switch serves as a reliable safety element within these digitally enhanced systems.