Siemens 5SN6340-8CN High Current High Breaking Capacity MCB 3P 40A

Siemens 5SN6340-8CN: High Current, High Breaking Capacity MCB for Robust Electrical Protection

The Siemens 5SN6340-8CN is a three-pole miniature circuit breaker (MCB) engineered for demanding industrial applications requiring high current handling and significant breaking capacity. This robust device offers superior protection against overloads and short circuits, ensuring the integrity and safety of electrical installations. Key advantages include its exceptionally low energy consumption, often one-third to half of standard definitions, leading to tangible electricity savings. The ergonomic design, featuring a user-friendly operating handle and a "sliding latch" mechanism, facilitates quick and secure mounting onto standard DIN rails or busbars, significantly enhancing installation efficiency and safety. Furthermore, its dust-proof and finger-safe terminal design minimizes the risk of electric shock and prolongs the operational lifespan of the unit, making the 5SN6340-8CN a reliable and cost-effective solution for critical power distribution.

Product Specifications

| Parameter              | Value                     |

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

| Product Number         | 5SN6340-8CN               |

| Type                   | Miniature Circuit Breaker |

| Poles                  | 3                         |

| Rated Current          | 40A                       |

| Breaking Capacity (Icu)| 6 kA (6kA according to EN 60898 and IEC 60947-2) |

| Rated Voltage          | 400V AC                   |

| Tripping Characteristic| D                         |

| Energy Limitation Class| 3                         |

| Degree of Pollution    | 2                         |

| Overvoltage Category   | III                       |

| Insulation Voltage     | 440V AC                   |

| Frequency              | 50/60 Hz                  |

| Width (Modular Units)  | 3                         |

| Depth                  | 76 mm                     |

| Installation Depth     | 70 mm                     |

| Ambient Operating Temp | -25°C to 45°C             |

| Connection Type        | Screw-type terminals      |

| Solid Conductor CSA    | 0.75 - 25 mm²             |

| Stranded Conductor CSA | 0.75 - 25 mm²             |

| Tightening Torque      | 2.5 - 3 N·m               |

| Net Weight             | 0.495 Kg                  |

| Protection Class       | IP20 (with connected conductors) |

Core Features & Market Positioning

The Siemens 5SN6340-8CN distinguishes itself through its commitment to energy efficiency, boasting remarkably low power consumption that translates directly into operational cost savings for end-users. This focus on sustainability aligns with current industry trends and stringent environmental regulations. Its market positioning is further solidified by Siemens' reputation for quality and reliability in industrial electrical components. The intuitive "sliding latch" mechanism for rail mounting is a significant user-experience advantage, simplifying installation and maintenance procedures, which are often critical factors in industrial settings where downtime is costly. The universal busbar design concept ensures compatibility with other Siemens circuit protection devices, offering flexibility in system design and integration. Its dust-proof and finger-safe terminal design directly addresses crucial safety concerns, providing enhanced protection against accidental contact and ingress of foreign particles, thereby increasing its appeal in environments where safety is paramount.

Key Application Scenarios

The Siemens 5SN6340-8CN is ideally suited for a broad spectrum of industrial and commercial applications where robust overcurrent protection is essential. Its high breaking capacity of 6 kA makes it particularly effective in distribution boards for manufacturing plants, large commercial buildings, and data centers, where fault currents can be substantial. It serves as a critical component in protecting circuits supplying heavy machinery, motors, and other inductive loads that draw high inrush currents, as indicated by its Type D tripping characteristic. In power distribution systems, it ensures reliable isolation of faulty sections, preventing damage to sensitive equipment and maintaining operational continuity. This MCB is also a suitable choice for protecting power circuits in infrastructure projects, such as substations and industrial complexes, where dependable and high-performance protection is a non-negotiable requirement.

Practical System Integration Guidance

Integrating the Siemens 5SN6340-8CN into existing or new electrical systems is streamlined due to its standardized design. Installation onto a 35mm DIN rail is facilitated by the accessible sliding latch, allowing for rapid attachment and removal. Proper wiring is crucial; the terminals accommodate conductor cross-sections ranging from 0.75 mm² to 25 mm² (solid or stranded), with a recommended tightening torque of 2.5 to 3 N·m to ensure secure connections and prevent overheating. For multi-pole installations, ensuring correct phase rotation and interconnections is vital. The device's dust-proof terminals require careful attention during wiring to maintain their integrity. While specific programming is not applicable to this mechanical protection device, correct upstream and downstream device coordination (e.g., with fuses or downstream MCBs) should be considered based on the overall system protection philosophy to ensure selective tripping and optimal fault discrimination.

Operation and Risk Mitigation

Operating the Siemens 5SN6340-8CN involves utilizing the clearly marked toggle handle to switch circuits on and off. The handle's position (up for ON, down for OFF) provides clear visual status indication. The MCB automatically trips and moves the handle to the OFF position in the event of an overload or short circuit. To reset after a trip, the handle must first be moved to the fully OFF position before switching back ON. Risk mitigation is inherent in the device's design: the finger-safe terminals and IP20 protection (when conductors are connected) prevent accidental contact. Its high breaking capacity protects against severe short-circuit events that could otherwise cause catastrophic equipment failure or fire. While this model does not typically report specific fault codes, understanding that a trip indicates a circuit fault (overload or short circuit) is key. Common troubleshooting involves identifying the cause of the trip, such as an overloaded circuit, a shorted appliance, or a wiring fault, and addressing it before resetting the MCB.

Scalability & Long-Term Value

The Siemens 5SN6340-8CN offers significant long-term value through its compatibility within the broader Siemens SENTRON protection device portfolio. While this specific MCB is a standalone protective component, its integration into larger distribution systems benefits from the standardized dimensions and connection interfaces common across Siemens' product lines. This ensures that as electrical demands evolve or system upgrades are planned, replacement or expansion using compatible Siemens components is readily achievable. The inherent durability and high-quality construction associated with Siemens industrial products contribute to a long operational lifespan, minimizing the need for premature replacement. For facilities looking towards digitalization, while the 5SN6340-8CN itself is not an IIoT-enabled device, it can be part of a larger, monitored electrical infrastructure where upstream or downstream intelligent devices provide data, with the 5SN6340-8CN acting as a foundational layer of protection.

Frequently Asked Questions (FAQs)

What is the primary function of the Siemens 5SN6340-8CN?

This MCB provides essential overcurrent protection. It safeguards electrical circuits from damage caused by overloads and short circuits, ensuring system safety and reliability.

It automatically interrupts the power flow when fault currents exceed its rated breaking capacity. This prevents overheating, fire hazards, and damage to connected equipment. Its primary role is active protection against electrical disturbances.

The Siemens 5SN6340-8CN is a critical component in distribution boards, industrial panels, and commercial installations. It ensures operational continuity by isolating faulty sections of the power grid.

What are the key technical specifications of the 5SN6340-8CN?

The unit is a 3-pole MCB with a 40A rated current and a 6 kA breaking capacity. It operates at 400V AC and features a Type D tripping characteristic for handling high inrush currents.

Its insulation voltage is 440V AC, with an energy limitation class of 3 and pollution degree of 2. The device is designed for DIN rail mounting and has a modular width of 3 units.

Connectivity is via screw-type terminals, supporting conductor cross-sections from 0.75 mm² to 25 mm². Its operating temperature range is -25°C to 45°C.

What is the breaking capacity of the Siemens 5SN6340-8CN?

The Siemens 5SN6340-8CN boasts a breaking capacity of 6 kA. This is specified for both EN 60898 and IEC 60947-2 standards, indicating its robust performance.

A 6 kA breaking capacity means it can safely interrupt fault currents up to 6000 Amperes without sustaining damage. This is suitable for many industrial and commercial power distribution systems.

This level of breaking capacity is crucial for environments where fault currents may be significant, ensuring the MCB can effectively protect the circuit and connected apparatus during severe electrical events.

What type of circuits is the 5SN6340-8CN suitable for?

The Type D tripping characteristic makes it ideal for circuits with high inrush currents. This includes applications like motor protection and transformer protection.

It is well-suited for industrial settings, machinery, and heavy-duty commercial applications where large inductive loads are common. Its 40A rating supports significant power delivery.

This MCB is designed for robust protection in power distribution panels, ensuring reliable operation even under demanding conditions. It safeguards against both gradual overloads and sudden short circuits.

How is the Siemens 5SN6340-8CN installed?

Installation is straightforward via the standard 35mm DIN rail mounting system. The device features a "sliding latch" for quick and secure attachment or removal.

Ensure proper conductor connections to the screw-type terminals, respecting the specified torque range (2.5-3 N·m) and conductor cross-section (0.75-25 mm²). Maintain finger-safe terminal protection.

For multi-pole configurations, ensure correct phase sequencing and interconnections. Always follow local electrical codes and safety standards during installation.

What are the benefits of the low energy consumption of this MCB?

Reduced energy consumption leads to direct operational cost savings. This translates to a lower electricity bill for the facility over the product's lifespan.

It contributes to environmental sustainability by minimizing the overall energy footprint of the electrical installation. Lower energy waste means reduced demand on power generation resources.

The low power consumption is achieved through advanced internal design, ensuring high efficiency without compromising protection capabilities. This offers a competitive edge and aligns with green building standards.

Is the 5SN6340-8CN suitable for residential use?

While designed for industrial robustness, its protective functions are applicable to circuits in larger residential complexes or high-demand homes. However, it is typically specified for higher-current industrial applications.

Residential installations often use MCBs with different tripping characteristics (like Type B or C) and lower breaking capacities, depending on the specific circuit loads. The Type D characteristic is less common in standard home wiring.

For most standard household circuits, a 40A Type D MCB would be over-specified and potentially lead to nuisance tripping. It's essential to match MCB type and rating to the specific load and circuit requirements.

What does the "3P" in 5SN6340-8CN signify?

"3P" indicates that the circuit breaker is a three-pole device. This means it is designed to simultaneously switch or protect three separate electrical conductors.

It is used for three-phase power systems, commonly found in industrial machinery and commercial power distribution. Each pole provides independent overcurrent protection.

By switching all three phases, it ensures complete disconnection of a three-phase load during fault conditions, preventing unbalanced currents or single-phased operation.

Can the 5SN6340-8CN be sealed?

Yes, the Siemens 5SN6340-8CN is designed to be sealable. This feature allows for tamper-proofing and controlled access to the circuit breaker's operational state.

Sealing is often employed in specific industrial or utility applications to prevent unauthorized operation or modification of the protection settings. It ensures that only authorized personnel can reset the breaker.

This can be crucial for maintaining system integrity and safety in critical infrastructure or secure facilities where operational continuity and unauthorized access control are paramount.

What is the warranty period for this Siemens MCB?

Siemens typically offers a standard warranty period for its industrial components, though specific terms can vary by region and distribution channel. For precise warranty information, it is best to consult the product documentation or the authorized Siemens distributor.

The warranty generally covers defects in materials and workmanship under normal operating conditions. It ensures the product's performance as specified for a defined period after purchase.

Purchasing from authorized Siemens partners is recommended to ensure authenticity and access to warranty services. Always retain proof of purchase for any warranty claims.