Siemens 5SU1656-7KK25 RCCB for Industrial Control System Protection 25A 300mA 1P+N C

The Siemens 5SU1656-7KK25 RCCB is a robust Residual Current Circuit Breaker (RCCB) engineered for high-performance industrial control system protection. This 25A, 300mA, 1P+N (single-pole plus neutral) device with a Type C tripping characteristic offers superior safety and operational continuity for critical electrical installations. Its core advantages lie in its reliable fault current detection, comprehensive protection against electric shock, and its capacity to prevent fire hazards arising from earth leakage. Key technical parameters include a rated current of 25A, a rated residual operating current of 300mA, and a nominal voltage of 230/400V AC. The Type C tripping curve ensures it can handle inrush currents from inductive loads common in industrial settings without nuisance tripping, while still providing rapid protection.

Product Specifications

| Feature                   | Specification                                    |

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

| Product Type              | Residual Current Circuit Breaker (RCCB)          |

| Siemens Model Number      | 5SU1656-7KK25                                    |

| Rated Current (In)        | 25A                                              |

| Rated Residual Operating Current (IΔn) | 300mA                                            |

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

| Tripping Characteristic   | Type C                                           |

| Rated Voltage (Un)        | 230/400V AC                                      |

| Rated Frequency           | 50/60 Hz                                         |

| Breaking Capacity (Icn)   | 10 kA (IEC 61009-1)                              |

| Terminal Type             | Screw Terminals                                  |

| Installation Type         | DIN Rail Mounting                                |

| Protection Class          | IP20 (Enclosure), IP40 (With cover)              |

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

| Compliance Standards      | IEC 61009-1, IEC 61009-2-1, GB13511, GB6829     |

Core Features & Market Positioning

The Siemens 5SU1656-7KK25 distinguishes itself in the industrial market through its uncompromising commitment to safety and operational integrity, a hallmark of Siemens' industrial automation portfolio. Its Type C tripping curve is a significant differentiator, specifically designed to accommodate the transient overcurrents typical of industrial machinery, such as motors and transformers, thereby minimizing unwanted shutdowns. This feature, combined with its high breaking capacity of 10kA, positions it as a robust solution for demanding environments where reliable protection against earth faults and indirect contact is paramount. The 300mA residual operating current is optimized for industrial applications where the primary concern is fire protection and significant equipment damage prevention, rather than personal protection against direct contact (which typically uses lower mA ratings). This focus on industrial-grade performance and reliability makes the 5SU1656-7KK25 a preferred choice for system integrators and maintenance engineers prioritizing uptime and asset protection.

Key Application Scenarios

This Siemens RCCB is ideally suited for safeguarding power circuits within industrial control systems, particularly those feeding inductive loads. Common scenarios include protecting motor control centers (MCCs), variable frequency drive (VFD) inputs, and power distribution boards for manufacturing machinery. Its application extends to areas requiring robust protection against earth leakage faults that could lead to equipment damage or fire, such as in chemical processing plants, heavy manufacturing facilities, and automated assembly lines. The 25A rating is appropriate for circuits supplying moderately sized industrial equipment, ensuring efficient and safe operation. Its use in environments with potential for high inrush currents, due to its Type C characteristic, makes it invaluable for protecting sensitive electronic controls and instrumentation within these industrial settings.

Practical System Integration Guidance

Integrating the Siemens 5SU1656-7KK25 RCCB into industrial control systems is straightforward, leveraging standard DIN rail mounting and screw terminal connections. For proper installation, ensure the RCCB is mounted vertically on a standard 35mm DIN rail. The incoming line conductor should be connected to the upper terminals (L and N), and the outgoing load conductors to the lower terminals. It is critical to connect the neutral conductor correctly to the 'N' terminal; reversing L and N can compromise the device's tripping function. Ensure all connections are torqued to the manufacturer's specifications to prevent overheating and ensure reliable contact. The device is designed to be installed upstream of the protected equipment, providing comprehensive earth fault protection for the entire circuit. Its 1P+N configuration simplifies wiring for single-phase circuits requiring neutral integrity.

Operation and Risk Mitigation

The primary function of the Siemens 5SU1656-7KK25 RCCB is to detect residual currents (imbalances between the live and neutral conductors) caused by earth faults. When such an imbalance exceeds the 300mA threshold, the RCCB rapidly disconnects the circuit, mitigating risks of electric shock, fire, and equipment damage. To ensure safe operation, always perform regular testing of the RCCB using its integrated test button (typically labeled 'T'). This test should be conducted monthly or as per site safety regulations to verify the tripping mechanism is functional. In case of frequent tripping, do not assume the device is faulty; instead, thoroughly inspect the protected circuit for insulation degradation or equipment faults. Overloading the circuit beyond its 25A rating will not cause the RCCB to trip unless an earth fault also occurs, necessitating the use of an appropriately rated miniature circuit breaker (MCB) in conjunction for overcurrent protection.

Scalability & Long-Term Value

The Siemens 5SU1656-7KK25 is designed for seamless integration into existing Siemens industrial control platforms, offering significant long-term value. Its compatibility with the broader Siemens SENTRON protective devices range ensures straightforward system expansion and upgrades. For facilities looking to enhance their Industrial Internet of Things (IIoT) capabilities, this RCCB can be integrated into smart electrical panels equipped with monitoring modules, allowing for remote diagnostics and predictive maintenance. This allows for tracking of fault events and operational status, contributing to increased system uptime and reduced maintenance costs. The robust construction and adherence to international standards guarantee a long service life, minimizing the need for premature replacement and ensuring consistent protection as industrial processes evolve.

Frequently Asked Questions

What is the primary function of the Siemens 5SU1656-7KK25 RCCB?

The Siemens 5SU1656-7KK25 RCCB's main role is to protect industrial electrical circuits. It detects earth leakage currents, preventing electric shock and fire hazards. This device ensures operational safety for equipment connected to the circuit.

This RCCB offers protection against indirect contact with live parts. It ensures personnel safety by rapidly disconnecting power when a fault occurs. It is crucial for maintaining safe working environments in industrial settings.

Its 300mA sensitivity is optimized for fire prevention and equipment safeguarding. This rating is typical for industrial applications where major damage is a concern. It complements overcurrent protection for comprehensive safety.

Can the Siemens 5SU1656-7KK25 be used for personal protection?

While it offers significant safety, the 300mA rating is primarily for fire and equipment protection. Personal protection against direct contact usually requires lower sensitivities like 10mA or 30mA. Always select the appropriate RCCB for the specific protection need.

For direct contact protection, lower residual current ratings are recommended. These lower ratings ensure quicker disconnection of power. Check local electrical codes for specific requirements.

The 5SU1656-7KK25 is designed for industrial fault current detection. It is best used in conjunction with other protective devices for complete safety coverage.

What does the 'C' in 5SU1656-7KK25 Type C signify?

The 'C' denotes the tripping characteristic of the RCCB. Type C breakers are designed to handle higher inrush currents typical of inductive loads. This includes motors, transformers, and solenoids.

This characteristic prevents nuisance tripping during normal equipment start-up. It allows for reliable operation of machinery with transient overcurrents. The RCCB will still trip for earth faults within its rated sensitivity.

For circuits with very high inrush currents, a Type D characteristic might be needed. However, Type C offers a good balance for most industrial control system applications.

What is the rated current of this Siemens RCCB?

The rated current for the Siemens 5SU1656-7KK25 is 25 Amperes (A). This indicates the maximum continuous current the device can safely handle without overheating. It is important to match this rating to the load requirements of the protected circuit.

Operating the circuit continuously above 25A may lead to excessive heat or premature failure of the device. Ensure the circuit's design current does not exceed this limit for safe and reliable performance. Always consult load calculations and relevant standards.

The 25A rating is suitable for a variety of industrial applications. It's essential to confirm this is appropriate for the specific machinery or control panel it will protect.

What is the breaking capacity of the 5SU1656-7KK25?

The breaking capacity (Icn) of the Siemens 5SU1656-7KK25 RCCB is 10 kA (kiloamperes). This rating signifies the maximum fault current the device can safely interrupt without sustaining damage. It ensures the RCCB can safely clear short-circuit conditions.

A 10kA breaking capacity is generally sufficient for most industrial distribution boards. It provides robust protection against severe electrical faults. This rating is in accordance with IEC 61009-1 standards.

This high breaking capacity is crucial for system integrity. It prevents cascading failures in the electrical network during a fault. It assures the reliability of the protection scheme.

How do I properly wire the Siemens 5SU1656-7KK25?

For proper wiring, connect the incoming line conductor to the upper 'L' terminal and the neutral conductor to the upper 'N' terminal. The outgoing load conductors are then connected to the corresponding lower 'L' and 'N' terminals. Ensure correct polarity.

Always ensure the neutral conductor is connected to the designated 'N' terminal on the RCCB. Incorrect wiring, especially swapping line and neutral, can impair or disable its protective function and pose safety risks. Tighten all connections securely to the specified torque.

This 1P+N (single-pole plus neutral) device requires both conductors to be connected for correct operation. Mount it on a standard 35mm DIN rail in a suitable enclosure for safety.

What is the purpose of the 300mA residual operating current?

The 300mA rated residual operating current (IΔn) signifies the threshold for earth leakage detection. When the current imbalance between live and neutral conductors exceeds this value, the RCCB trips. This level is optimized for industrial fire protection.

This sensitivity helps prevent fires caused by persistent earth faults. It protects equipment and infrastructure from significant damage due to sustained leakage. It is a key feature for industrial asset safeguarding.

While effective for fire prevention, lower mA ratings (e.g., 30mA) are typically used for enhanced personal protection against direct contact. The 300mA rating prioritizes preventing catastrophic failures and fire events.

Does the Siemens 5SU1656-7KK25 offer overcurrent protection?

No, the Siemens 5SU1656-7KK25 is a Residual Current Circuit Breaker (RCCB). Its primary function is earth leakage protection. It does not inherently provide overcurrent or short-circuit protection.

For complete circuit protection, it is standard practice to combine an RCCB with an appropriately rated Miniature Circuit Breaker (MCB). The MCB provides overcurrent and short-circuit protection, while the RCCB adds earth fault protection.

Always install an MCB in series with or upstream of the RCCB to cover all protection needs. Refer to electrical design guidelines for correct system configuration.

Can this RCCB be used in outdoor industrial environments?

The Siemens 5SU1656-7KK25 has an enclosure protection rating of IP20 for the device itself. This means it is protected against solid objects larger than 12.5mm but is not designed for direct exposure to water or harsh outdoor elements.

For outdoor installations or in environments with significant moisture or dust, the RCCB must be housed within a suitable enclosure (e.g., an IP54 or higher rated control panel). This external enclosure provides the necessary environmental protection.

Always ensure the overall installation complies with relevant industrial safety and environmental standards for the specific application site. The enclosure's integrity is crucial for device longevity and safety.

What is the Siemens product family for this RCCB?

The Siemens 5SU1656-7KK25 belongs to the Siemens SENTRON protective devices range. This family encompasses a wide array of circuit breakers, residual current devices, and other protection components for industrial and residential applications.

SENTRON products are known for their reliability, safety, and compatibility within Siemens' broader automation and electrical distribution portfolio. This allows for integrated and efficient electrical system design.

The 5SU series, specifically, offers robust performance for industrial control systems. It is engineered to meet the demanding requirements of modern manufacturing and processing facilities.