Siemens 5SU9356-7KK32 Double Pole RCBO 32A 30mA 1P+N C

The Siemens 5SU9356-7KK32 is a high-performance, double-pole Residual Current Circuit Breaker with Overcurrent protection (RCBO), engineered for reliable electrical safety in demanding industrial and commercial applications. This unit combines the functions of a Miniature Circuit Breaker (MCB) and a Residual Current Device (RCD) into a single, compact device, offering superior protection against overcurrents, short circuits, and dangerous earth leakage currents. Its C-curve tripping characteristic makes it ideal for circuits with moderate inrush currents, such as those found with motors or lighting systems. With a rated current of 32A and a residual current sensitivity of 30mA, the Siemens 5SU9356-7KK32 provides robust personal protection and prevents damage to connected equipment by quickly interrupting power when fault conditions are detected.

Product Specifications

| Specification                  | Value                                           |

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

| Product Type                   | RCBO (Residual Current Circuit Breaker with Overcurrent protection) |

| Manufacturer                   | Siemens                                         |

| Model Number                   | 5SU9356-7KK32                                   |

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

| Rated Current (In)             | 32A                                             |

| Residual Current (IΔn)         | 30mA                                            |

| Tripping Characteristic        | Type C                                          |

| Breaking Capacity (Icn)        | 6 kA                                            |

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

| Frequency                      | 50/60 Hz                                        |

| Terminal Type                  | Screw Terminals                                 |

| Mounting                       | DIN Rail (35mm)                                 |

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

| Degree of Protection           | IP20                                            |

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

Core Features & Market Positioning

The Siemens 5SU9356-7KK32 distinguishes itself through its advanced hybrid overcurrent release technology, offering precise and reliable tripping performance. Its double-pole design ensures complete disconnection of both the live and neutral conductors, a critical safety feature for many installations. The integration of residual current detection directly within the overcurrent protection device streamlines panel design and reduces component count, leading to cost and space savings. Siemens' reputation for high-quality, durable electrical components positions this RCBO as a premium choice for applications where reliability and safety are paramount, setting it apart from single-function devices or lower-tier manufacturers. The C-curve characteristic is a key differentiator for specific industrial loads.

Key Application Scenarios

This Siemens 5SU9356-7KK32 RCBO is exceptionally well-suited for protecting circuits in commercial buildings, industrial facilities, and workshops. Its 32A rating and C-curve make it ideal for general power distribution, lighting circuits with inductive loads, and circuits supplying small to medium-sized motors where temporary overcurrents during startup are common. It provides essential protection against electric shock for personnel and mitigates fire hazards caused by earth faults in circuits powering machinery, HVAC systems, and processing equipment. In residential settings, it can be used for circuits supplying high-power appliances or those with a greater risk of earth leakage.

Practical System Integration Guidance

Integrating the Siemens 5SU9356-7KK32 into existing or new electrical panels is straightforward due to its standard 35mm DIN rail mounting and screw terminal connections. Ensure that the incoming live and neutral conductors are connected to the appropriate terminals, and the outgoing conductors are connected to the load terminals. Always adhere to local electrical codes and regulations during installation. For optimal performance, ensure that the neutral conductor is properly terminated and not switched by other devices upstream. Proper earthing of the enclosure and equipment connected to the RCBO is crucial for effective residual current protection. Cross-connection of multiple RCBOs using busbars is common practice for efficient distribution.

Operation and Risk Mitigation

The Siemens 5SU9356-7KK32 operates by continuously monitoring the balance of current flowing through the live and neutral conductors. If an imbalance exceeding 30mA occurs, indicating a potential earth leakage fault, the device trips rapidly, disconnecting the power supply. The C-curve characteristic ensures that it will not trip on temporary, harmless current surges up to five to ten times the rated current, which is common for inductive loads. In the event of a fault, the toggle will move to the OFF position. If the RCBO trips frequently, investigate the connected circuit for persistent earth faults, overloaded conditions, or incompatible equipment. Ensure that the device is correctly rated for the circuit's prospective fault current.

Scalability & Long-Term Value

The Siemens 5SU9356-7KK32 offers excellent long-term value and integration capabilities. As part of the broader Siemens SENTRON protection devices portfolio, it ensures compatibility with other Siemens circuit breakers, RCDs, and associated accessories, allowing for scalable protection solutions as a facility's electrical demands evolve. Its robust construction and adherence to international standards guarantee a long service life and reliable operation, minimizing the need for premature replacements. While this specific model is a standalone unit, its integration within a well-designed Siemens electrical system facilitates future upgrades and expansions, maintaining system integrity and safety.

FAQs

What is the primary function of a Siemens 5SU9356-7KK32 RCBO?

This device offers combined overcurrent and residual current protection. It safeguards against short circuits and overloads. It also detects earth leakage currents to prevent electric shock.

It provides essential safety for personnel and equipment. The RCBO acts as both a circuit breaker and an RCD in one. This saves space and simplifies panel wiring.

The 5SU9356-7KK32 offers 32A current handling and 30mA earth leakage sensitivity. Its C-curve tripping is suitable for inductive loads.

How does the C-curve tripping characteristic benefit industrial applications?

The C-curve allows for higher inrush currents during startup. This is crucial for motors and transformers. It prevents nuisance tripping on transient surges.

Industrial equipment often has temporary current spikes. The C-curve accommodates these without interrupting normal operation. This ensures system stability and productivity.

For applications with significant inductive loads, like certain pumps or fans, the C-curve is preferred over a B-curve. It balances protection with operational needs.

What are the key technical parameters for the Siemens 5SU9356-7KK32?

This RCBO is double-pole, covering both live and neutral conductors. It has a 32A rated current and 30mA residual current sensitivity. Its breaking capacity is 6kA.

It operates on 230/400V AC at 50/60Hz. The C-curve tripping characteristic is important for its application suitability. It is designed for DIN rail mounting.

These specifications ensure it meets safety standards like IEC/EN 61009-1. Its IP20 degree of protection is suitable for enclosed electrical installations.

Can the Siemens 5SU9356-7KK32 be used for both residential and industrial settings?

Yes, its versatility allows for use in both. In residential settings, it's excellent for high-power circuits. It provides crucial protection against earth faults.

In industrial environments, it's ideal for machinery and distribution boards. Its C-curve suits motor loads and inductive equipment common there.

The 30mA sensitivity is a standard for personal protection, making it suitable across many scenarios where safety is a priority.

What type of loads is the Siemens 5SU9356-7KK32 most suitable for with its C-curve?

The C-curve is designed for circuits with moderate inductive or capacitive inrush currents. Examples include lighting systems with transformers. It's also suited for small to medium-sized electric motors.

This characteristic prevents unwanted tripping during the initial power-up phase. Such surges are typical for equipment that contains coils or switches. It ensures continuous operation where needed.

Circuits powering pumps, fans, vending machines, and compressors often benefit from a C-curve RCBO. It provides protection without excessive sensitivity to startup transients.

What does "Double Pole (1P+N)" signify for this RCBO?

"Double Pole (1P+N)" means it switches and protects both the live (L) and neutral (N) conductors. This ensures complete isolation of the circuit. It is essential for many safety regulations.

When the RCBO trips, both the live and neutral lines are disconnected simultaneously. This prevents potential hazards from a live conductor remaining connected. It's a critical safety feature.

This feature is particularly important in systems where the neutral conductor carries load current and must be disconnected for full isolation, unlike single-pole devices that only switch the live wire.

What is the breaking capacity (Icn) of the Siemens 5SU9356-7KK32 and why is it important?

The breaking capacity (Icn) of 6kA indicates the maximum fault current it can safely interrupt. This protects the circuit and connected equipment from severe damage. It's a critical safety rating.

Ensuring the Icn is higher than the prospective short-circuit current at the installation point is vital. This prevents the RCBO from failing catastrophically during a fault. It guarantees reliable protection.

Selecting an RCBO with adequate breaking capacity is crucial for safety and compliance with electrical standards. It prevents dangerous arc flash incidents during short circuits.

How do you correctly install the Siemens 5SU9356-7KK32 RCBO?

Mount the RCBO securely onto a standard 35mm DIN rail. Connect the incoming live and neutral wires to the top terminals. Ensure correct polarity.

Connect the outgoing load wires to the bottom terminals. Ensure the neutral conductor from the supply is connected to the RCBO's neutral terminal and is not bypassed. Proper earthing of the enclosure is vital.

Always consult local electrical codes and manufacturer instructions. Perform insulation resistance tests and functional tests after installation before energizing the circuit.

What are the consequences of frequent tripping of the Siemens 5SU9356-7KK32?

Frequent tripping indicates an underlying issue in the electrical circuit. It could be a persistent earth leakage fault. Overloading of the circuit is another common cause.

Investigate the connected appliances and wiring for any damage or faults. Ensure the connected load does not exceed the RCBO's 32A rating continuously. Transient surges may also be a factor if it's a C-curve.

Persistent tripping without an obvious fault could indicate an internal device issue or incompatibility with the circuit's characteristics. Professional diagnosis is recommended to resolve the problem.

How does the 30mA residual current sensitivity contribute to safety?

A 30mA residual current sensitivity is the standard for personal protection against electric shock. It detects small imbalances in current flow. This indicates a leakage path to earth, often through a person.

When this level of leakage is detected, the RCBO trips very quickly, within milliseconds. This rapid disconnection limits the duration and severity of the electric shock. It significantly reduces the risk of serious injury or fatality.

This sensitivity is crucial for socket outlets and circuits supplying appliances used in potentially damp environments. It ensures a high level of safety for individuals interacting with electrical systems.