Siemens 5SV3644-8 Miniature Circuit Breaker (MCB) 4P 40A 300mA

The Siemens 5SV3644-8 Miniature Circuit Breaker (MCB) is a robust 4-pole, 40A, 300mA device engineered for superior electrical protection in demanding industrial and commercial environments. Its advanced tripping characteristics and high breaking capacity ensure reliable safeguarding against overcurrents and earth faults, minimizing downtime and protecting sensitive equipment. With a commitment to safety and efficiency, this MCB stands out for its compact design, ease of installation, and long-term operational value, making it an ideal choice for modern electrical distribution systems.

Product Specifications

| Feature               | Specification                                |

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

| Manufacturer          | Siemens                                      |

| Product Type          | Miniature Circuit Breaker (MCB)              |

| Model Number          | 5SV3644-8                                    |

| Number of Poles       | 4P (4 Poles)                                 |

| Rated Current (In)    | 40A                                          |

| Rated Residual Current| 300mA                                        |

| Tripping Curve        | Type C                                       |

| Breaking Capacity (Icn)| 6 kA                                         |

| Voltage Rating (Ue)   | 400V AC                                      |

| Frequency             | 50/60 Hz                                     |

| Insulation Voltage (Ui)| 500V                                         |

| Degree of Protection  | IP20 (with connected conductor)              |

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

| Mounting Type         | DIN Rail (35mm)                              |

| Terminal Type         | Box terminal with wire protection            |

| Standards Compliance  | IEC/EN 60898-1, IEC/EN 61009-1               |

Core Features & Market Positioning

The Siemens 5SV3644-8 distinguishes itself through its high breaking capacity of 6 kA, providing a significant safety margin for fault current interruption in applications where robust protection is paramount. Its integrated earth-leakage protection with a 300mA sensitivity effectively detects residual currents, preventing electrical fires and protecting personnel from indirect contact. As a Type C tripping curve device, it is specifically designed to handle moderate inrush currents from inductive loads, such as motors and transformers, without nuisance tripping, thereby enhancing operational stability. This combination of features positions the 5SV3644-8 as a premium solution for electrical installations requiring reliable, high-performance circuit protection that meets stringent international safety standards.

Key Application Scenarios

This 4-pole, 40A MCB is exceptionally well-suited for main distribution boards in commercial buildings, offering comprehensive protection for lighting, heating, and general power circuits. Its 300mA residual current sensitivity makes it a critical component in sub-distribution boards for industrial facilities, safeguarding machinery and personnel against earth faults in environments with higher electrical loads and potential for transient disturbances. Furthermore, the 5SV3644-8 is an excellent choice for protecting circuits supplying large appliances or motor loads in residential complexes and multi-dwelling units, where the integrity of the electrical system and user safety are of utmost importance.

Practical System Integration Guidance

Installation of the Siemens 5SV3644-8 MCB onto a standard 35mm DIN rail is straightforward, facilitated by its compact 4-module width design. The device features robust box terminals with integrated wire protection, ensuring secure and reliable connections for conductors up to 16mm² rigid or 10mm² flexible, preventing premature wire fatigue and ensuring optimal conductivity. For proper functioning of the residual current protection, it is crucial to ensure that all live conductors of the circuit are routed through the MCB's terminals; the neutral conductor must also be connected to its designated terminal for the earth fault detection mechanism to operate correctly. Adherence to local electrical codes and standards during wiring is essential.

Operation and Risk Mitigation

The 5SV3644-8 operates by continuously monitoring the current flowing through the live conductors. If an imbalance occurs, indicating a fault current to earth exceeding 300mA, the internal mechanism rapidly trips, disconnecting all poles and interrupting the power supply. This significantly reduces the risk of electric shock and potential fire hazards. In the event of a tripping, always identify the cause of the fault before resetting the breaker. Overloading, short circuits, or persistent earth leakage are common reasons for a trip. Avoid repeatedly attempting to reset a breaker that trips immediately, as this can indicate a serious electrical issue requiring professional diagnosis.

Scalability & Long-Term Value

The Siemens 5SV3644-8 MCB is designed for seamless integration within Siemens' broader Sentron protection, switching, measuring, and monitoring devices portfolio, allowing for future expansion and upgrades. Its adherence to international standards ensures compatibility with a wide range of ancillary components and systems, simplifying the process of building more complex electrical installations or retrofitting existing ones. While this specific model focuses on core protection, its robust construction and Siemens' reputation for quality engineering contribute to a long operational lifespan, offering excellent long-term value by minimizing maintenance requirements and replacement costs.

Frequently Asked Questions

1. What is the primary function of the Siemens 5SV3644-8 MCB?

The Siemens 5SV3644-8 MCB acts as a crucial safety device in electrical systems. It provides overcurrent protection against overload and short circuits. Additionally, its integrated 300mA residual current detection safeguards against earth faults.

This MCB ensures the protection of electrical circuits, wiring, and connected equipment from damage. It also plays a vital role in preventing electrical fires and protecting people from severe electric shocks.

The device combines the functions of a miniature circuit breaker and a residual current device (RCD) into a single, compact unit for enhanced safety and convenience.

2. How does the 300mA residual current protection work in the 5SV3644-8?

The 300mA residual current sensitivity detects imbalances between the live and neutral conductors. Such an imbalance signifies current leaking to earth, potentially through a person or faulty equipment.

When the leakage current exceeds 300mA, the MCB's internal RCD mechanism quickly interrupts the power supply. This rapid disconnection minimizes the risk of serious injury or fire.

It is essential that all live conductors and the neutral conductor for the protected circuit pass through the MCB for the residual current detection to function accurately.

3. Can the Siemens 5SV3644-8 MCB be used for both residential and industrial applications?

Yes, this MCB is highly versatile and suitable for a broad range of applications. Its 40A rating and 6kA breaking capacity are ideal for demanding industrial settings.

In residential settings, it is excellent for main distribution boards or sub-panels protecting multiple circuits. It ensures robust protection for appliances and general power distribution.

The combination of overcurrent and earth fault protection makes it a comprehensive safety solution for diverse electrical installations requiring reliable circuit interruption.

4. What does the '4P' in Siemens 5SV3644-8 signify?

'4P' stands for four poles. This indicates that the circuit breaker has four separate switching elements, one for each of the live conductors and the neutral conductor in a 3-phase system, plus an additional pole for a neutral if required, or all three phases plus neutral in specific configurations.

For a 4-pole MCB, it provides simultaneous switching of all connected conductors. This ensures that when the breaker trips, all live conductors and the neutral are disconnected, providing complete isolation from the power source.

This feature is particularly important in systems where the neutral conductor is switched and can carry current, such as in certain industrial or IT earthing systems.

5. What is the significance of the 'Type C' tripping curve on this MCB?

The 'Type C' tripping curve indicates the MCB's response to overcurrents. It is designed to withstand moderate inrush currents commonly experienced with inductive loads.

These loads, such as motors, transformers, and fluorescent lighting ballasts, can draw several times their normal operating current for a brief moment upon startup. A Type C breaker will not trip during these short, high inrush events.

However, it will still trip quickly in response to short circuits, offering a balance between sensitivity to faults and tolerance for transient overloads.

6. What is the breaking capacity (Icn) of the Siemens 5SV3644-8, and why is it important?

The breaking capacity (Icn) of 6 kA (kiloamperes) signifies the maximum fault current the MCB can safely interrupt without sustaining damage. This is a critical safety parameter for electrical installations.

A higher breaking capacity is essential in locations where the potential fault current from the power supply is high, such as near a transformer or the main incoming supply. It ensures the breaker can safely de-energize the circuit during a severe short circuit.

Choosing an MCB with an adequate breaking capacity prevents catastrophic failure of the device, which could lead to fires or further damage to the electrical system.

7. How do I properly install the Siemens 5SV3644-8 MCB?

Installation involves securely mounting the MCB onto a standard 35mm DIN rail within an appropriate enclosure. Ensure the rail is properly grounded.

Connect the incoming live and neutral conductors to the designated terminals at the top of the MCB, and the outgoing conductors to the terminals at the bottom. Use appropriately sized conductors and ensure secure connections with the wire protection feature.

It is imperative to follow all local electrical codes and regulations during installation. If unsure, consult a qualified electrician to ensure safe and compliant installation.

8. What troubleshooting steps should I take if the Siemens 5SV3644-8 MCB trips?

First, determine if the trip was due to an overload or an earth fault. If it's an overload, reduce the connected load and reset the breaker.

If the trip persists or appears to be an earth fault (indicated by frequent tripping or specific fault conditions), identify and isolate the faulty circuit or appliance. Check wiring for damage or short circuits.

Never force a tripped breaker back on; always investigate the cause of the trip thoroughly. Persistent tripping often requires professional diagnosis to ensure system safety and integrity.

9. What is the voltage rating (Ue) for this MCB, and what does it mean?

The voltage rating (Ue) of 400V AC signifies the maximum alternating voltage at which the circuit breaker is designed to operate safely and effectively. This is suitable for typical European mains power systems.

It means the MCB can be used in circuits operating at or below 400V AC. Using it on a higher voltage system would exceed its design limits and pose a significant safety hazard.

Always ensure the voltage rating of the MCB matches the voltage of the electrical system you are installing it into for safe and reliable operation.

10. Does the Siemens 5SV3644-8 support smart grid or IoT integration?

This specific model, the 5SV3644-8, is a standard electromechanical circuit breaker and does not inherently possess smart capabilities for direct IoT integration or remote monitoring. Its primary function is robust, reliable circuit protection.

However, Siemens offers a range of connected devices and communication modules that can be integrated into electrical panels alongside standard MCBs. These modules can provide data on energy consumption, status, and fault events.

For smart grid or IIoT applications, consider pairing this MCB with Siemens' digital monitoring relays or communication gateways to achieve remote visibility and control within your electrical infrastructure.