Siemens 5SY6403-7CC Single Phase Standard Load Circuit Breaker 4P 3A

The Siemens 5SY6403-7CC is a 4-pole, 3A, single-phase standard load circuit breaker designed for robust protection in electrical distribution systems. Its core advantage lies in its reliable tripping mechanism, ensuring immediate disconnection under overload or short-circuit conditions, thereby safeguarding connected equipment and preventing hazards. Key technical parameters include a rated voltage of 400V and a breaking capacity of 6kA, indicative of its suitability for a wide range of residential, commercial, and light industrial applications. This circuit breaker exemplifies Siemens' commitment to quality and safety in electrical protection devices.

Product Specifications

| Feature                 | Specification                                 |

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

| Manufacturer            | Siemens                                       |

| Model                   | 5SY6403-7CC                                   |

| Poles                   | 4                                             |

| Rated Current           | 3A                                            |

| Rated Voltage           | 400V                                          |

| Breaking Capacity (Icn) | 6kA                                           |

| Tripping Characteristic | C Curve                                       |

| Connection Type         | Screw Terminal                                |

| Mounting                | DIN Rail (35mm)                               |

| Width                   | 70 mm                                         |

| Standards               | IEC, UL (depending on specific model variant) |

Core Features & Market Positioning

The Siemens 5SY6403-7CC circuit breaker is positioned as a dependable and cost-effective solution for essential circuit protection. Its 6kA breaking capacity makes it suitable for standard load applications where fault currents are not exceptionally high, differentiating it from heavy-duty industrial breakers. The C-curve tripping characteristic ensures a balance between protecting sensitive equipment and allowing for brief inrush currents common in motor start-ups or lighting circuits. This makes it a preferred choice for electrical contractors and panel builders seeking reliable performance without unnecessary over-specification, aligning with the broader Siemens strategy of offering a comprehensive range of electrical components that meet diverse market needs for safety, efficiency, and durability.

Key Application Scenarios

This 4-pole, 3A circuit breaker finds its primary utility in protecting individual circuits within residential electrical panels, small commercial installations, and light industrial settings. Common applications include safeguarding lighting circuits, socket outlets, and small appliances. Its four-pole design is particularly useful for applications requiring the simultaneous disconnection of all live conductors and the neutral, such as in certain single-phase systems or for specific safety requirements. Electricians and installers rely on the 5SY6403-7CC for its straightforward integration into standard distribution boards, ensuring compliance with safety regulations for branch circuit protection.

Practical System Integration Guidance

Installing the Siemens 5SY6403-7CC is a standard procedure for qualified electricians. The breaker mounts directly onto a 35mm DIN rail, a ubiquitous standard in electrical enclosures. Wiring involves connecting the incoming power to the line terminals (typically on one side) and the outgoing load circuits to the load terminals (on the opposite side). For a 4-pole breaker, all four terminals on both the line and load sides must be correctly wired to their respective conductors (L1, L2, L3, N or equivalent for single-phase with neutral disconnect). It is crucial to ensure that the power source is de-energized before commencing installation and that all connections are tight to prevent overheating.

Operation and Risk Mitigation

The primary function of the Siemens 5SY6403-7CC is automatic tripping to interrupt current flow during overcurrent events. Overloads, which are sustained currents exceeding the rated 3A, will cause thermal tripping, while short circuits, characterized by very high currents, will trigger magnetic tripping. Users should be aware that improper installation, such as loose connections or incorrect conductor sizing, can lead to overheating and premature failure. Regular visual inspection for any signs of damage or discoloration is recommended. In the event of nuisance tripping, a thorough investigation of the connected load is necessary to identify the cause, rather than assuming a faulty breaker.

Scalability & Long-Term Value

While the 5SY6403-7CC is designed for specific load protection, its value extends through compatibility with a wide ecosystem of Siemens electrical components and adherence to international standards. It integrates seamlessly into Siemens-manufactured distribution boards and can be part of larger electrical systems designed with scalability in mind. The robust construction typical of Siemens products ensures longevity, reducing the need for frequent replacements and contributing to lower lifetime operational costs. Its adherence to standards like IEC also ensures that it remains a relevant component for future system upgrades or expansions, particularly in regions where these standards are mandated.

Frequently Asked Questions (FAQs)

1. What is the breaking capacity of the Siemens 5SY6403-7CC?

The Siemens 5SY6403-7CC circuit breaker features a breaking capacity of 6kA. This rating indicates the maximum fault current it can safely interrupt without sustaining damage. It is designed for standard load applications, offering adequate protection against short circuits in residential and light commercial settings.

This 6kA rating ensures reliable protection for circuits where fault currents are not expected to exceed this level. It is a common specification for miniature circuit breakers used in many standard electrical installations.

Choosing a breaker with an appropriate breaking capacity is crucial for system safety. The 5SY6403-7CC is suitable for applications adhering to this fault current limit.

2. Can the Siemens 5SY6403-7CC be used for motor protection?

Yes, the Siemens 5SY6403-7CC, with its C-curve characteristic, can be used for circuits supplying small motors. The C-curve provides a slight delay, accommodating the temporary inrush current when a motor starts. However, it is not designed for direct motor overload protection, which often requires specialized motor protection relays or breakers with specific thermal and magnetic settings.

For dedicated motor protection, it is advisable to consult the motor's nameplate and select a circuit breaker or protection device specifically designed for motor starting characteristics and overload sensitivity. This ensures optimal protection and operational reliability.

The 3A rating of this particular breaker suggests it is intended for very low-power motors or loads that draw a consistent, low current. Always verify the motor's full load amperage against the breaker's rating.

3. How do I wire a 4-pole Siemens 5SY6403-7CC circuit breaker?

Wiring the 4-pole 5SY6403-7CC involves connecting the incoming power supply to the line terminals and the outgoing load to the load terminals. For a 4-pole breaker, you will connect to all four line terminals and all four load terminals.

Ensure that the live conductors and the neutral conductor are connected to their corresponding terminals on both the line and load sides. The order of connection is critical for proper circuit operation and safety.

Always de-energize the circuit before wiring. Verify connections are secure and that the breaker is properly seated on the DIN rail for correct operation.

4. What is the significance of the 'C' curve on the Siemens 5SY6403-7CC?

The 'C' curve designation on the 5SY6403-7CC indicates its tripping characteristic for short-circuit currents. A C-curve breaker trips between 5 to 10 times its rated current, providing a balance between sensitivity and accommodating inrush currents.

This characteristic is ideal for circuits with moderate inductive loads, such as lighting systems or small motors, where transient current surges are common during startup. It prevents nuisance tripping while still offering protection.

Compared to a B-curve (3-5 times rated current), a C-curve offers delayed tripping, making it suitable for applications where temporary overcurrents are expected but should not cause a shutdown.

5. Is the Siemens 5SY6403-7CC suitable for DC applications?

The Siemens 5SY6403-7CC is primarily designed as a single-phase AC circuit breaker. While some miniature circuit breakers can be adapted for DC use, it is generally not recommended without specific DC ratings and configurations.

Using an AC-rated breaker in a DC circuit can lead to arcing issues and a failure to interrupt the circuit safely. DC circuits have different arc-quenching requirements compared to AC circuits.

Always refer to the product datasheet or manufacturer's specifications to confirm suitability for DC applications. If DC protection is required, select a breaker specifically rated for DC voltage and current.

6. Where can I find a datasheet for the Siemens 5SY6403-7CC?

Datasheets for the Siemens 5SY6403-7CC can typically be found on the official Siemens Industry Online Support portal or through authorized Siemens distributors. Searching the Siemens website using the product number will usually yield relevant technical documentation.

These datasheets provide comprehensive details on the product's specifications, dimensions, electrical characteristics, and compliance with various international standards. They are essential for proper selection and installation.

Distributors' websites often link to manufacturer datasheets or provide their own detailed product specification sheets, which are valuable resources for project planning.

7. What is the warranty period for the Siemens 5SY6403-7CC?

Warranty information for electrical components like the 5SY6403-7CC can vary by region and distributor. Generally, new Siemens products come with a manufacturer's warranty, often for one year from the date of purchase, provided they are installed and operated according to specifications.

It is recommended to check with the specific supplier or distributor at the time of purchase to confirm the exact warranty terms and conditions. This ensures clarity on coverage and claim procedures.

In some cases, extended warranties or service agreements may be available for larger projects or specific applications. Always retain proof of purchase for warranty claims.

8. What are the dimensions and mounting requirements for this breaker?

The Siemens 5SY6403-7CC is designed for standard 35mm DIN rail mounting, a common standard in electrical enclosures. Its width is typically 70mm, accommodating its 4-pole configuration.

The compact design allows for efficient use of space within electrical distribution boards and control panels, facilitating high-density installations. Ensuring a secure DIN rail fit is crucial for stable electrical contact.

Always confirm the exact dimensions and mounting instructions in the product's technical documentation to ensure compatibility with your enclosure and other components.

9. What is the difference between a 5SY6403-7CC and a 5SY6403-7?

The 'CC' suffix in the Siemens 5SY6403-7CC model number often denotes specific regional standards, packaging, or minor variations in accessories or manufacturing location compared to a base model like the '5SY6403-7'. The core electrical specifications (poles, current, voltage, breaking capacity) are typically identical.

These slight variations are common in electrical component numbering to distinguish between different product lines or market-specific versions. For most practical purposes in a standard AC application, their protective functions will be equivalent.

Always cross-reference the full model number with the datasheet to confirm any subtle differences, especially if precise compliance with a specific standard is required.

10. Can this breaker be used in an outdoor enclosure?

While the Siemens 5SY6403-7CC is designed for reliable operation, its suitability for outdoor use depends heavily on the environmental conditions and the enclosure it's installed in. Standard miniature circuit breakers are typically rated for indoor use or within enclosures providing adequate protection against moisture, dust, and UV radiation.

For outdoor applications, the circuit breaker must be housed within an appropriately rated enclosure (e.g., NEMA 3R or IP-rated enclosure) that protects it from direct environmental exposure. The enclosure must also ensure proper ventilation if required for heat dissipation.

Always consult the product's IP (Ingress Protection) rating and the environmental specifications to determine its suitability for outdoor installation, or ensure that the chosen enclosure provides the necessary protection.