Siemens 5SU1656-1KK40 High Current Type A Earth Leakage Protector 40A 300mA 1P+N C
The Siemens 5SU1656-1KK40 is a high-performance, Type A Earth Leakage Protector designed for robust protection in demanding electrical installations. This 1P+N (single-pole + neutral) device offers a substantial 40A current rating and a sensitivity of 300mA, making it ideal for safeguarding circuits against dangerous residual currents, thereby preventing electric shock and mitigating fire hazards. Its C-curve tripping characteristic ensures it accommodates inrush currents commonly found in industrial and commercial settings without unnecessary nuisance tripping, balancing sensitivity with operational reliability.
Product Specifications
| Parameter | Specification |
| :---------------------------- | :------------------------------------------ |
| Product Type | Earth Leakage Protector |
| Model Number | 5SU1656-1KK40 |
| Rated Current (In) | 40A |
| Rated Residual Current (IΔn) | 300mA |
| Pole Configuration | 1P+N (Single-pole + Neutral) |
| Tripping Curve | C-Curve |
| Voltage Rating | 230/400V (AC) |
| Frequency | 50/60 Hz |
| Breaking Capacity (Icn) | 6kA |
| Protection Type | Type A (Detects AC and pulsating DC residual currents) |
| Mounting | DIN Rail |
| Operating Temperature | -25°C to +45°C |
| Insulation Voltage (Ui) | 500V |
| Degree of Protection (IP) | IP20 |
Core Features & Market Positioning
The Siemens 5SU1656-1KK40 distinguishes itself through its Type A sensing capability, a critical differentiator that expands its protective scope beyond standard Type AC devices. This means it reliably detects both sinusoidal alternating current (AC) residual currents and pulsating direct current (DC) residual currents, which are increasingly prevalent with modern electronic equipment such as variable frequency drives and LED lighting. Its robust 40A rating and 6kA breaking capacity position it as a reliable solution for heavier industrial loads where circuit integrity and fault current management are paramount. The C-curve characteristic further solidifies its market appeal by offering a balance between sensitive earth leakage detection and tolerance for moderate inductive or capacitive loads, minimizing operational disruptions. This combination of advanced sensing, high current handling, and application-specific tripping behavior makes the 5SU1656-1KK40 a premium choice for applications demanding enhanced safety and operational stability.
Key Application Scenarios
This earth leakage protector is exceptionally well-suited for a variety of industrial and commercial environments. Its primary application is in main distribution boards and sub-distribution panels where it serves to protect circuits supplying machinery, control systems, and power outlets. Specific use cases include protecting circuits in manufacturing plants, workshops, and areas with a high concentration of inductive loads that could generate pulsating DC residual currents. It is also an excellent choice for installations incorporating sensitive electronic equipment, such as server rooms or control cabinets, where reliable protection against earth faults is crucial to prevent data loss or system downtime. The 300mA sensitivity is appropriate for general protection against fire and electric shock, aligning with many international electrical codes for industrial settings.
Practical System Integration Guidance
Integrating the Siemens 5SU1656-1KK40 into existing electrical systems is a straightforward process, leveraging standard DIN rail mounting for quick and secure installation. The device features clearly labeled terminals for line (L) and neutral (N) input and output, facilitating correct polarity and connection. For a 1P+N device, ensuring the line and neutral conductors are connected to the designated input terminals is crucial; the load is then connected to the corresponding output terminals. It is imperative to observe the correct connection sequence, typically connecting the line conductor to the terminal marked 'L' and the neutral conductor to the terminal marked 'N' on both the input and output sides. Always ensure that the incoming power supply is de-energized before commencing any wiring. The device's integrated trip mechanism is factory-set and does not require user programming. When integrating with other protective devices, such as circuit breakers, proper coordination is essential to ensure selective tripping, although the 6kA breaking capacity of the 5SU1656-1KK40 provides a significant level of fault current interruption capability.
Operation and Risk Mitigation
The Siemens 5SU1656-1KK40 operates by continuously monitoring the balance of current flowing through the line and neutral conductors. If an imbalance occurs—indicating that current is leaking to earth through a fault or an unintended path—the device rapidly trips, interrupting the circuit and preventing potential hazards. The Type A functionality is key to mitigating risks associated with both AC and pulsating DC leakage currents, which can be generated by solid-state electronics. This protects against electric shock by quickly disconnecting power, thereby reducing the duration of contact with a live conductor. Furthermore, by interrupting fault currents, it significantly reduces the risk of electrical fires caused by overheating or arcing. Regular testing of the earth leakage protection function using the integrated test button is a critical risk mitigation strategy. This button simulates a leakage current, ensuring the device's tripping mechanism is functioning correctly. Users should conduct these tests periodically, following manufacturer guidelines and local electrical codes.
Scalability & Long-Term Value
The Siemens 5SU1656-1KK40 offers significant long-term value through its compatibility with the broader Siemens SENTRON system and its inherent reliability. As electrical infrastructure evolves, this earth leakage protector can be seamlessly integrated into larger Siemens power distribution systems, ensuring future upgrades or expansions maintain a high standard of safety. Its robust construction and adherence to stringent quality standards mean a long operational lifespan, reducing the need for premature replacement. While not directly an IIoT-enabled device in itself, its presence in a smart electrical panel contributes to overall system safety and operational continuity, which are foundational elements for any digital transformation initiative. Compatibility with standard DIN rail mounting also ensures it can be easily replaced or supplemented by future generations of Siemens protective devices without requiring extensive panel modifications, preserving the investment in the electrical infrastructure.
Frequently Asked Questions
What is the primary function of the Siemens 5SU1656-1KK40?
Its main role is to detect and interrupt electrical circuits when a dangerous earth leakage current occurs. This protects people from electric shock.
It provides safety by quickly disconnecting power if current flows to earth. This also helps prevent electrical fires caused by faults. The 300mA sensitivity is key for this protection.
The device is crucial for compliance with safety regulations in industrial and commercial settings. It ensures a higher level of electrical system safety.
Can this earth leakage protector detect DC residual currents?
Yes, the 5SU1656-1KK40 is a Type A device, meaning it detects AC and pulsating DC residual currents. This is vital for modern electronics.
Many electronic devices, like VFDs and LED drivers, can create pulsating DC leakage. Type A protection is necessary for these scenarios. It offers broader protection than Type AC devices.
This feature makes it suitable for a wider range of applications, including those with sensitive electronic loads. It enhances overall system safety and reliability.
What does the 'C' in C-Curve refer to for this Siemens protector?
The C-Curve designation indicates its tripping characteristic for overcurrents. It means the device can handle moderate inrush currents.
This feature is important for circuits with inductive loads, like motors or transformers. It prevents nuisance tripping during normal startup surges. The protector still offers sensitive earth fault detection.
Therefore, it strikes a balance between protecting against earth faults and avoiding unwanted shutdowns in typical industrial environments. It is designed for operational stability.
How does the 40A rating affect its application?
The 40A rating signifies the maximum continuous current the protector can safely handle. It's suitable for circuits with significant power demands.
This makes it appropriate for use in main distribution panels or sub-panels feeding substantial loads. It can protect circuits for machinery or groups of equipment.
Users must ensure the circuit's normal operating current does not exceed 40A to maintain safe and reliable operation. It's designed for higher current industrial applications.
Is the Siemens 5SU1656-1KK40 suitable for residential use?
While effective, its 40A rating and 300mA sensitivity are more typically suited for industrial or commercial applications. Residential applications often use lower current ratings and 30mA sensitivity.
The C-curve is also more common in industrial settings for managing motor start-up currents. Residential circuits might not require this specific tripping characteristic.
However, it can be used residentially if the circuit demands the 40A capacity and the 300mA sensitivity meets local code requirements for specific areas. Always consult local electrical codes.
What is the purpose of the test button on the device?
The test button allows users to periodically verify the earth leakage protection function is operational. It simulates a fault condition.
By pressing the button, a small leakage current is introduced, forcing the protector to trip. This confirms the internal mechanism is working correctly.
Regular testing (monthly is often recommended) is crucial for ensuring the device provides continuous safety. It's a key part of maintenance for earth leakage protection.
What does '1P+N' mean for this protector?
'1P+N' signifies that the device protects a single phase (1 Pole) and also switches the neutral conductor. It provides a complete isolation.
This ensures that both the live and neutral wires are disconnected from the circuit when a fault occurs. This is a critical safety feature for complete circuit isolation.
For circuits where the neutral is switched, this configuration is essential for comprehensive protection and maintenance safety. It ensures both conductors are disconnected.
What is the breaking capacity (Icn) of 6kA?
The 6kA breaking capacity indicates the maximum fault current the protector can safely interrupt without being damaged. It is rated for significant fault conditions.
This rating ensures that in the event of a short circuit, the device can safely disconnect the power supply. This prevents catastrophic damage to the equipment and wiring.
It signifies a robust level of protection against high fault currents, common in industrial power distribution systems. It is designed for robust fault management.
Does this device require any special wiring considerations?
Standard wiring practices for DIN rail mounted devices apply. Ensure correct line and neutral connections to the designated terminals.
Always de-energize the circuit before making any connections. Verify correct polarity to ensure proper operation and safety.
The internal mechanism does not require any external programming or complex setup procedures. It is designed for straightforward integration.
How does the Type A classification differ from Type AC?
Type A protectors can detect both sinusoidal AC residual currents and pulsating DC residual currents. Type AC only detects sinusoidal AC residual currents.
Modern electronic devices often generate pulsating DC leakage currents. A Type A protector is necessary to reliably detect these potentially hazardous situations.
Therefore, Type A offers enhanced safety and broader application suitability compared to Type AC, especially with evolving electrical loads. It is a more advanced protection standard.
