Siemens 5SN6240-8CN High Breaking Capacity Miniature Circuit Breaker 2P 40A

The Siemens 5SN6240-8CN is a high-performance 2-pole, 40A miniature circuit breaker (MCB) engineered for robust protection in demanding electrical installations. This device offers exceptional breaking capacity, ensuring safety and reliability by swiftly interrupting fault currents. Its advanced tripping mechanisms provide precise overcurrent and short-circuit protection, safeguarding sensitive equipment and preventing electrical hazards. Designed for industrial and commercial applications, the 5SN6240-8CN exemplifies Siemens' commitment to quality, innovation, and operational excellence in power distribution.

Product Specifications

| Feature                  | Specification                               |

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

| Manufacturer             | Siemens                                     |

| Model                    | 5SN6240-8CN                                 |

| Pole Configuration       | 2-Pole                                      |

| Rated Current (In)       | 40A                                         |

| Breaking Capacity (Icn)  | 6 kA                                        |

| Voltage Rating (Ue)      | 400V AC                                     |

| Frequency                | 50/60 Hz                                    |

| Tripping Curve           | C                                           |

| Insulation Voltage (Ui)  | 500V                                        |

| Impulse Withstand Voltage | 4 kV                                        |

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

| Protection Class         | IP20                                        |

| Mounting                 | DIN Rail (35mm)                             |

| Terminal Type            | Screw terminals                             |

| Compliance               | IEC/EN 60898-1                              |

| Certifications           | CE, CCC                                     |

Core Features & Market Positioning

The Siemens 5SN6240-8CN stands out in the industrial MCB market due to its superior breaking capacity of 6 kA, offering a significant safety margin for fault interruption. Its Type C tripping curve is optimized for applications with moderate inrush currents, such as those found in motor control circuits and lighting systems, providing sensitive protection without nuisance tripping. This MCB is built to the rigorous IEC/EN 60898-1 standard, ensuring consistent performance and reliability. As part of the Siemens Sentron protection devices portfolio, the 5SN6240-8CN benefits from extensive research and development, positioning it as a dependable choice for critical infrastructure.

Key Application Scenarios

This 2-pole, 40A miniature circuit breaker is ideally suited for protecting power circuits in industrial control panels, building distribution systems, and machinery enclosures. Its robust design and 6 kA breaking capacity make it a prime selection for safeguarding inductive loads and equipment susceptible to moderate current surges. Common applications include branch circuit protection, motor overload and short-circuit protection, and the overall safeguarding of electrical circuits in commercial facilities where reliable and efficient power management is paramount. The 5SN6240-8CN ensures operational continuity and asset protection across diverse industrial environments.

Practical System Integration Guidance

Integrating the Siemens 5SN6240-8CN into existing electrical systems is straightforward due to its standard 35mm DIN rail mounting. The unit features clearly marked screw terminals for secure conductor connections, accommodating appropriate wire gauges for a 40A rating. Proper wiring involves connecting the line conductor to the upper terminal and the load to the lower terminal when viewed from the front. Ensure that all connections are tightened to the torque specifications recommended by Siemens to prevent overheating and ensure optimal electrical conductivity. Overcurrent protection settings are inherent to the C-curve and do not require external adjustment.

Operation and Risk Mitigation

The Siemens 5SN6240-8CN operates by detecting overcurrents exceeding its calibrated threshold, initiating a rapid mechanical trip to open the circuit and de-energize the load. This action mitigates the risk of thermal damage to conductors, prevents equipment failure due to overloads, and significantly reduces the potential for electrical fires caused by short circuits. To ensure safe operation, regular visual inspections for physical damage and periodic testing of the tripping mechanism are recommended. Proper electrical grounding and adherence to local electrical codes during installation are crucial for comprehensive risk mitigation.

Scalability & Long-Term Value

The 5SN6240-8CN is designed for compatibility within the broader Siemens industrial control and automation ecosystem. Its standard form factor and adherence to international standards facilitate seamless integration with other Siemens Sentron protection devices, motor starters, and control components. This inherent compatibility ensures that electrical distribution systems can be easily expanded or upgraded without compromising the integrity of existing protection schemes. While this specific model is a standalone protection device, its robust construction and reliable performance contribute to the long-term operational value and reduced maintenance requirements of the overall electrical infrastructure.

FAQs

What is the breaking capacity of the Siemens 5SN6240-8CN?

The Siemens 5SN6240-8CN offers a breaking capacity of 6 kA. This signifies its ability to safely interrupt fault currents up to this level. It is a crucial safety feature for protecting electrical systems from severe short circuits.

This high breaking capacity ensures that in the event of a fault, the MCB will quickly and reliably disconnect the circuit. This prevents damage to connected equipment and reduces the risk of electrical fires. It meets stringent industry standards for fault current interruption.

The 6 kA rating makes the 5SN6240-8CN suitable for a wide range of industrial and commercial applications where fault currents can be significant. This includes protecting branch circuits in power distribution panels.

What type of tripping curve does the 5SN6240-8CN use?

This MCB features a Type C tripping curve. This curve is designed for circuits with moderate inductive or capacitive loads. It allows for a higher inrush current without tripping.

Type C curves typically trip between 5 to 10 times the rated current. This makes them ideal for protecting equipment like motors and transformers that experience temporary current surges upon startup. It balances sensitivity with protection against nuisance tripping.

The 5SN6240-8CN's Type C curve ensures reliable operation in environments where connected loads might briefly exceed the nominal current. This avoids unnecessary shutdowns while still providing essential overcurrent and short-circuit protection.

What are the primary applications for the Siemens 5SN6240-8CN?

This circuit breaker is primarily used for branch circuit protection in industrial and commercial installations. Its 40A rating suits various power distribution needs. It ensures safety for equipment and personnel.

It is commonly deployed in control panels and distribution boards. The 5SN6240-8CN protects motors, lighting circuits, and general power outlets from overloads and short circuits. Its robust construction ensures longevity.

Key applications include safeguarding machinery, ensuring stable power for sensitive electronics, and providing a reliable safety barrier in building electrical systems. Its versatile 2-pole design makes it suitable for single-phase applications requiring a neutral disconnect.