Technical Review: Siemens 5SU9356-1CN20 Leakage Protection Switch - Selection Guide & Specs
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Overview
Electrical safety is paramount in industrial and commercial settings, where undetected ground faults can lead to equipment damage, production downtime, and serious safety hazards. The Siemens 5SU9356-1CN20 Leakage Protection Switch addresses this critical need by providing reliable protection against electrical leakage currents that conventional circuit breakers cannot detect. This advanced RCCB (Residual Current Circuit Breaker) combines overcurrent protection with sensitive leakage detection to safeguard personnel and equipment in demanding applications.
Technical Specifications
| Parameter | Specification |
|---|---|
| Model Number | 5SU9356-1CN20 |
| Rated Current | 20A |
| Rated Voltage | 230V AC |
| Leakage Sensitivity | 30mA |
| Number of Poles | 1P+N |
| Breaking Capacity | 6kA |
| Tripping Characteristic | Type C |
| Protection Mode | Dual Mode (AC/DC) |
| Standards Compliance | IEC/EN 61008-1, IEC/EN 61009-1 |
| Mounting | DIN Rail (35mm) |
| Operating Temperature | -25°C to +55°C |
| Mechanical Life | 20,000 operations |
| Electrical Life | 10,000 operations at rated current |
Technical Analysis
The Siemens 5SU9356-1CN20 represents the pinnacle of electrical safety technology, combining the functions of a miniature circuit breaker with advanced residual current protection. The 30mA sensitivity threshold provides optimal protection against electric shock while minimizing nuisance tripping from normal system leakage. The Type C tripping characteristic offers protection against moderate inrush currents, making it suitable for applications with small motors and transformers.
The dual-mode protection capability ensures reliable operation with both AC and pulsating DC residual currents, providing comprehensive protection in modern electrical systems where electronic equipment can generate DC components. The 6kA breaking capacity ensures the device can safely interrupt high short-circuit currents, protecting downstream equipment and wiring.
Buying Considerations
When selecting the Siemens 5SU9356-1CN20 or similar leakage protection devices, consider these critical factors:
- Load Assessment: Ensure the 20A rating matches your circuit requirements. Calculate total connected load and consider future expansion
- Application Environment: Verify the -25°C to +55°C operating temperature range suits your installation location
- System Compatibility: Confirm compatibility with existing electrical distribution systems and upstream protection devices
- Installation Requirements: Plan for DIN rail mounting and adequate space for wiring connections
- Maintenance Schedule: Regular testing using the integrated test button is essential for continued reliability
- Regulatory Compliance: Ensure the device meets local electrical codes and safety standards
Frequently Asked Questions
What is the difference between Type AC and Type A RCCB protection?
Type AC RCCBs protect against alternating residual currents only, while Type A devices (like the Siemens 5SU9356-1CN20) provide protection against both AC and pulsating DC residual currents. Type A is essential for circuits containing electronic equipment like variable frequency drives, computers, or LED lighting that can generate DC leakage currents.
How often should I test the leakage protection switch?
Manufacturers recommend testing RCCBs monthly using the integrated test button. This verifies the mechanical operation and electronic circuitry. Additionally, professional testing with specialized equipment should be conducted annually as part of your electrical maintenance program to ensure proper sensitivity and response time.
Can this device be used as the main switch for a sub-distribution board?
Yes, the Siemens 5SU9356-1CN20 is suitable for use as a main switch in sub-distribution applications. Its 6kA breaking capacity and 20A rating make it appropriate for protecting smaller distribution circuits. However, always verify that the upstream protection device coordinates properly and consult local electrical regulations for specific installation requirements.
