Siemens 5SU9156-7KK25 Industrial Earth Leakage Protection Switch RCCB 25A 10mA 1P+N C

The Siemens 5SU9156-7KK25 is a high-performance industrial Earth Leakage Protection Switch (RCCB) designed for robust safety and reliability in demanding electrical environments. This 1-pole + neutral device boasts a 25A rated current and a sensitive 10mA tripping current, providing superior protection against electrical shocks and fire hazards caused by insulation faults. Its Type C tripping characteristic ensures it can handle moderate inrush currents without nuisance tripping, making it ideal for industrial machinery and sensitive electronic equipment. The 5SU9156-7KK25 offers essential safety functions, compact design, and Siemens' renowned quality for critical power distribution applications.

Product Specifications

| Feature               | Specification                                      |

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

| Product Type          | Earth Leakage Protection Switch (RCCB)             |

| Manufacturer          | Siemens                                            |

| Model Number          | 5SU9156-7KK25                                      |

| Rated Current (I n )  | 25 A                                               |

| Rated Residual Current | 10 mA                                              |

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

| Tripping Characteristic | Type C                                             |

| Rated Voltage (U n )  | 230/400 V                                          |

| Frequency             | 50/60 Hz                                           |

| Breaking Capacity     | 6 kA                                               |

| Mounting Type         | DIN Rail                                           |

| Terminal Type         | Screw Terminal                                     |

| Degree of Protection  | IP20                                               |

| Operating Temperature | -25 °C to +55 °C                                   |

Core Features & Market Positioning

The Siemens 5SU9156-7KK25 stands out in the industrial safety market due to its precision 10mA residual current detection, offering a critical layer of protection against dangerous earth faults that could otherwise lead to severe electric shock or fires. Its Type C tripping characteristic is a significant advantage, differentiating it from Type B or A devices by allowing for higher transient currents common in motor starts and inductive loads without triggering unwarranted shutdowns. This feature positions the 5SU9156-7KK25 as a robust solution for environments where operational continuity is paramount, alongside stringent safety requirements. Siemens' established reputation for manufacturing high-quality, reliable electrical components further solidifies its market standing as a trusted choice for industrial safety applications.

Key Application Scenarios

This Siemens RCCB is exceptionally suited for protecting circuits in industrial settings where personnel and equipment are at risk from earth leakage faults. Common applications include motor control centers, power distribution boards for manufacturing equipment, and protection for sensitive electronic loads in automation systems where a 10mA sensitivity is mandated for enhanced safety. Its 25A rating and Type C characteristic make it ideal for circuits powering machinery with moderate inductive loads or inrush currents, such as pumps, fans, and small to medium-sized motors. Furthermore, it is frequently employed in commercial buildings and specialized industrial facilities requiring advanced protection against indirect contact.

Practical System Integration Guidance

Integrating the Siemens 5SU9156-7KK25 into existing electrical systems is straightforward due to its standard DIN rail mounting and screw terminal connections. Ensure the incoming live and neutral conductors are connected to the designated L and N terminals, respectively, and the outgoing protected circuit conductors are connected to the corresponding output terminals. The neutral conductor must be connected according to the wiring diagram to ensure proper functioning of the earth leakage detection. For optimal protection, it should be installed upstream of the loads it is intended to safeguard, typically in a main distribution board or sub-distribution panel. Always consult the product manual for specific torque values and wiring best practices to ensure safe and reliable operation.

Operation and Risk Mitigation

The primary function of the Siemens 5SU9156-7KK25 is to rapidly disconnect the electrical circuit when an earth leakage current exceeding 10mA is detected, significantly mitigating the risk of electric shock to personnel and preventing potential fire hazards. In the event of a fault, the RCCB will trip, interrupting the power supply. To reset the device after a trip, first identify and rectify the cause of the earth leakage. Then, the switch can be reset by pushing the lever upwards. Regular testing using a dedicated RCCB tester is crucial to verify its operational integrity, ensuring the 10mA tripping threshold and disconnection time remain within specified limits for ongoing risk mitigation.

Scalability & Long-Term Value

The Siemens 5SU9156-7KK25 offers excellent long-term value through its robust construction and compatibility with standard Siemens industrial electrical components, ensuring seamless integration within existing or future Siemens-based electrical infrastructure. Its inclusion in the comprehensive Siemens product portfolio means it aligns with broader system solutions, including industrial control and automation platforms. While the 5SU9156-7KK25 is a dedicated safety device, its reliable performance contributes to the overall stability and longevity of the electrical system, minimizing downtime and associated operational costs. For evolving industrial needs, it can be readily incorporated into upgraded distribution panels, supporting the transition towards more sophisticated and interconnected IIoT environments.

Frequently Asked Questions

What is the primary function of the Siemens 5SU9156-7KK25 RCCB?

The Siemens 5SU9156-7KK25 is an industrial Earth Leakage Protection Switch. Its main role is to detect imbalances in current flow. It rapidly disconnects power if an earth fault is sensed.

This prevents electric shocks and fire hazards. It is designed for high reliability in industrial settings. It offers crucial safety for personnel and equipment.

The device operates by monitoring the current going into and out of a circuit. If these currents differ by more than 10mA, it trips. This ensures swift protection against dangerous leakage currents.

Why is the tripping characteristic "Type C" important for this industrial RCCB?

A Type C tripping characteristic means the RCCB can tolerate higher inrush currents. These surges occur when inductive loads, like motors, start up. It prevents nuisance tripping in such scenarios.

This makes the 5SU9156-7KK25 suitable for industrial machinery. It ensures operational continuity where motors or transformers are present. It balances safety with the demands of industrial power.

Unlike Type B, Type C offers better immunity to transient currents. This reduces unnecessary shutdowns. It is a key feature for industrial applications with fluctuating loads.

How do I correctly wire the Siemens 5SU9156-7KK25 for optimal earth leakage protection?

Connect the incoming live wire to the designated 'L' terminal. Connect the incoming neutral wire to the 'N' terminal. Ensure these are on the input side of the device.

The outgoing protected circuit live and neutral wires connect to the output terminals. Follow the diagram on the device or in the manual precisely. Incorrect wiring compromises safety.

Always use appropriate conductor sizes for the 25A rating. Ensure all connections are secure and torqued correctly. Double-check wiring against schematics before energizing the circuit.

What does a 10mA residual current rating signify for this Siemens RCCB?

A 10mA residual current rating indicates a high sensitivity to earth leakage. This level is often required for enhanced personal protection. It trips at a lower fault current than standard 30mA devices.

This sensitivity is crucial for protecting individuals from severe electric shock. It can detect smaller insulation faults early. This minimizes risk in demanding industrial environments.

The 10mA rating ensures rapid disconnection. It is particularly valuable in damp or conductive environments. It provides an advanced safety margin against indirect contact.

Can the Siemens 5SU9156-7KK25 be used in residential applications, or is it strictly for industrial use?

While primarily designed for industrial settings, the 5SU9156-7KK25 can be used in residential applications. Its 10mA sensitivity offers superior protection against electric shock. This is often desired for specific circuits.

However, standard residential RCCBs typically have a 30mA rating for general use. The 10mA version is more sensitive and might be specified for areas with higher risk. Always check local electrical codes for requirements.

Its Type C characteristic is also beneficial for homes with significant motor-driven appliances. Using a 10mA device ensures a high level of safety, but cost and specific application needs should be considered.

What is the breaking capacity (kA) of the 5SU9156-7KK25, and why is this parameter critical?

The 5SU9156-7KK25 has a breaking capacity of 6 kA. This indicates its ability to safely interrupt fault currents up to 6000 amperes without damage. This is a critical safety parameter.

A higher breaking capacity ensures the device can withstand severe short-circuit currents. It prevents catastrophic failure during a fault. This protects the rest of the electrical installation.

This 6 kA rating is suitable for many industrial sub-distribution circuits. It is important to ensure this capacity is adequate for the specific installation's prospective fault current. Matching this parameter prevents over-reliance on the device.

What is the significance of the "1P+N" designation for this RCCB?

"1P+N" signifies that the switch has one protected pole and one neutral pole. Both the live and neutral conductors are switched simultaneously. This ensures complete isolation of the circuit.

This configuration is standard for single-phase circuits in many installations. It provides protection for both conductors. It is crucial for safety and proper operation of certain equipment.

Having both poles switched by the RCCB is important for reliable earth fault detection. It ensures the neutral conductor does not carry current independently if a fault occurs. This enhances overall safety.

How does the Siemens 5SU9156-7KK25 integrate with other Siemens industrial control and automation products?

This RCCB integrates as a fundamental safety component within broader Siemens solutions. It provides essential circuit protection for power supplied to PLCs, drives, and other automation devices. Its standardized form factor fits easily into Siemens control panels.

Siemens electrical components are designed for system compatibility. The 5SU9156-7KK25 works seamlessly with Siemens circuit breakers, contactors, and motor starters. This ensures a cohesive and reliable electrical system architecture.

For IIoT applications, this device ensures the foundational electrical safety. It protects the network infrastructure and connected industrial assets. Its data can contribute to overall system monitoring and diagnostics if linked via intelligent gateways.

What are common troubleshooting steps if the Siemens 5SU9156-7KK25 trips frequently?

First, investigate the cause of the earth leakage fault. This could be damaged insulation on wiring or connected equipment. Test connected appliances and machinery individually.

Disconnect all loads from the circuit protected by the RCCB. If the RCCB still trips, the fault may be within the RCCB itself or the upstream wiring. If it does not trip, the fault lies with one of the loads.

Ensure the upstream supply voltage and frequency are within specifications. Check for any signs of overheating or physical damage to the RCCB. If problems persist, replacement by a qualified electrician is recommended.

How often should the Siemens 5SU9156-7KK25 be tested to ensure its reliability?

Regular testing is critical for maintaining the RCCB's protective function. It is recommended to perform manual tests monthly or quarterly. This is done using the integrated test button on the device.

For accurate verification of tripping current and time, a dedicated RCCB tester should be used. This professional testing is typically done annually or biennially. This ensures compliance with safety standards.

The results of these tests should be documented. This provides a record of the device's performance over time. It helps in planning for eventual replacement and ensures ongoing safety.