Siemens 5SU1356-1KK20 Residual Current Protector RCCB 20A 30mA 1P+N C

The Siemens 5SU1356-1KK20 is a highly reliable 20A, 30mA, 1P+N (single-pole + neutral) Residual Current Circuit Breaker (RCCB) with a Type C tripping characteristic, engineered for robust protection in demanding industrial and commercial environments. This RCCB excels in safeguarding electrical installations against dangerous earth fault currents, providing essential protection against electric shock and fire hazards. Its key advantages lie in its high breaking capacity, ensuring swift disconnection during fault conditions, and its precise 30mA sensitivity, which is crucial for personal protection. The Type C characteristic allows it to handle inrush currents associated with inductive loads without nuisance tripping, making it ideal for motor circuits and other equipment with significant temporary current surges.

Product Specifications

| Specification          | Value                                     |

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

| Manufacturer           | Siemens                                   |

| Product Series         | 5SU1                              |

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

| Model Number           | 5SU1356-1KK20                           |

| Rated Current (I n )   | 20 A                                      |

| Rated Residual Current | 30 mA                                     |

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

| Tripping Characteristic| Type C                                    |

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

| Frequency              | 50/60 Hz                                  |

| Breaking Capacity (I c ) | 6 kA                                      |

| Insulation Voltage     | 500 V                                     |

| Degree of Protection   | IP20 (enclosure), IP4X (terminal area)    |

| Terminal Type          | Cage clamp terminals                      |

| Mounting Type          | DIN rail 35 mm                            |

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

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

Core Features & Market Positioning

The Siemens 5SU1356-1KK20 stands out in the market due to its robust construction and adherence to stringent international safety standards, including IEC/EN 61009. Its Type C tripping curve offers superior performance over Type B or A in applications prone to transient overcurrents, such as those involving motors, transformers, and fluorescent lighting, minimizing unnecessary disconnections and maintaining operational continuity. This differentiates it from basic RCCBs that might trip prematurely under such conditions. Siemens' reputation for quality and reliability further solidifies the 5SU1356-1KK20's position as a preferred choice for electricians and system designers prioritizing safety and operational efficiency. Its compact design also facilitates installation in standard distribution boards, offering a space-saving solution.

Key Application Scenarios

This Siemens RCCB is extensively used in residential, commercial, and industrial settings where enhanced protection against earth leakage and electric shock is paramount. Its 20A rating and 30mA sensitivity make it ideal for protecting circuits supplying lighting, sockets, and small to medium-sized appliances, particularly in areas with higher humidity or where prolonged contact with electrical equipment is possible, such as kitchens, bathrooms, and workshops. The Type C characteristic specifically targets applications involving inductive loads, including control circuits, vending machines, and small motor-driven equipment found in building services and light manufacturing environments. It's a critical component in ensuring compliance with electrical safety regulations for these types of installations.

Practical System Integration Guidance

Integrating the Siemens 5SU1356-1KK20 into an electrical system is straightforward due to its standard DIN rail mounting and cage clamp terminals. Ensure the main power supply is de-energized before commencing any work. Connect the line conductor to terminal L and the neutral conductor to terminal N on the input side, typically from the upstream protective device or busbar. The load-side connections for the protected circuit's live and neutral conductors are made to the corresponding output terminals. Proper conductor sizing and termination are crucial; use conductors with adequate cross-sectional area and ensure all connections are tight to prevent overheating. The 1P+N configuration requires both live and neutral conductors to be connected through the RCCB to ensure complete circuit protection.

Operation and Risk Mitigation

The Siemens 5SU1356-1KK20 operates by continuously monitoring the current balance between the live and neutral conductors. If an imbalance exceeding 30mA is detected, indicative of current flowing through an unintended path (like a person or faulty insulation), the RCCB rapidly trips, interrupting the circuit. This significantly reduces the risk of electric shock and prevents fires caused by persistent earth faults. To mitigate risks, regular testing of the RCCB is recommended using its integrated test button (usually labeled 'T'). This test should be performed periodically, as per local electrical codes, to verify the tripping mechanism is functioning correctly. Avoid connecting high inrush current loads directly without considering the Type C characteristic; for significantly larger inductive loads, a higher-rated RCCB or a Type C circuit breaker may be more appropriate.

Scalability & Long-Term Value

The Siemens 5SU1356-1KK20 is designed for seamless integration within Siemens' broader electrical distribution system portfolio, offering excellent compatibility with other Siemens components like miniature circuit breakers (MCBs) and surge protective devices (SPDs). This ensures that as electrical installations evolve or expand, the 5SU1356-1KK20 can remain a core component, contributing to a unified and reliable protection strategy. While this specific unit offers fixed performance parameters, its scalability lies in its ability to be incorporated into larger, modular distribution boards, supporting the addition of more circuits or higher-rated protection devices as needed. Its robust design and Siemens' commitment to product longevity contribute to its long-term value, minimizing the need for frequent replacements in well-maintained systems.

Frequently Asked Questions

Q1: What is the primary function of the Siemens 5SU1356-1KK20 RCCB?

This device provides essential protection against earth leakage currents. It safeguards personnel from electric shock hazards. It also helps prevent fires caused by electrical faults.

Q2: What does the "30mA" rating signify for this RCCB?

It indicates the sensitivity of the device. A 30mA fault current will trigger a disconnection. This level is considered safe for personal protection.

Q3: Why is the "Type C" tripping characteristic important for this model?

Type C is suitable for inductive loads. It allows for higher inrush currents without nuisance tripping. This is common with motors and transformers.

Q4: Can this RCCB be used for single-phase and three-phase circuits?

The "1P+N" designation means it's for single-phase circuits. It protects one live conductor and the neutral. It is not designed for three-phase applications.

Q5: How often should I test the Siemens 5SU1356-1KK20?

Regular testing is crucial for reliability. It is recommended to test monthly. Always follow local electrical safety regulations.

Q6: What is the breaking capacity of this RCCB?

It has a breaking capacity of 6 kA. This means it can safely interrupt fault currents up to this level. This ensures protection during severe short circuits.

Q7: Where is the Siemens 5SU1356-1KK20 typically installed?

It is commonly installed in electrical distribution boards. It mounts onto a standard 35mm DIN rail. This ensures easy and secure installation.

Q8: Can this RCCB protect against overloads and short circuits?

No, its primary function is earth leakage protection. Overloads and short circuits are handled by miniature circuit breakers (MCBs). This RCCB complements MCBs.

Q9: What ambient temperatures are suitable for this product?

This RCCB operates reliably in temperatures from -25°C to +45°C. Extreme temperatures can affect performance. Ensure it's installed within this range.

Q10: What is the degree of protection for this specific model?

The enclosure offers IP20 protection. The terminal area has IP4X protection. This suits typical indoor electrical panel environments.