# BR-20 4P Type 2 20kA Surge Protective Device for TNS Systems
## Introduction to Surge Protection in TNS Systems
The BR-20 4P Type 2 20kA Surge Protective Device (SPD) is specifically designed for TNS (Terre-Neutral-Separated) electrical systems. This advanced protection device plays a crucial role in safeguarding electrical installations against transient overvoltages caused by lightning strikes or switching operations.
## Key Features of the BR-20 4P SPD
High Performance Protection
With a nominal discharge current (In) of 20kA per pole, the BR-20 4P offers superior protection against electrical surges. Its Type 2 classification indicates it’s designed for installation at the distribution board level, providing secondary protection after the main Type 1 SPD.
4-Pole Design for TNS Systems
The 4-pole configuration is specifically optimized for TNS earthing arrangements, ensuring comprehensive protection between all active conductors (L1, L2, L3) and neutral (N), as well as between neutral and earth (PE).
Advanced Thermal Protection
The device incorporates thermal disconnection technology that automatically disconnects the SPD from the circuit in case of overheating or end-of-life conditions, preventing potential fire hazards.
## Technical Specifications
| Parameter | Value |
|---|---|
| Type | Type 2 SPD |
| Nominal Discharge Current (In) | 20kA (8/20μs) |
| Maximum Discharge Current (Imax) | 40kA (8/20μs) |
| Voltage Protection Level (Up) | <2.5kV |
| Response Time | <25ns |
| Operating Voltage | 230/400V AC |
## Installation Considerations
Proper Mounting
The BR-20 4P should be installed as close as possible to the distribution board it’s protecting, with short and straight connections to minimize inductive effects. Follow the manufacturer’s guidelines for proper cable sizing and routing.
System Coordination
For optimal protection, the BR-20 4P should be used in coordination with upstream Type 1 SPDs (when required) and downstream Type 3 SPDs for point-of-use protection, creating a comprehensive surge protection strategy.
Maintenance and Monitoring
While the device features visual status indicators, regular inspection is recommended. Some models may offer remote monitoring capabilities through auxiliary contacts for integration with building management systems.
## Benefits for TNS Electrical Systems
- Enhanced equipment protection against both common-mode and differential-mode surges
- Reduced downtime and maintenance costs by preventing surge-related damage
- Compliance with IEC 61643-11 and other relevant standards
- Compact design for easy integration into existing distribution boards
- Reliable performance across a wide temperature range
## Conclusion
The BR-20
