Chint 4P Surge Protector NXU-II 40/385

Chint 4P Surge Protector NXU-II 40/385 is a Class T2 surge protective device (SPD) specifically designed for three-phase four-wire power distribution systems. It is suitable for protecting against lightning and operational overvoltage in residential, commercial, and industrial scenarios. The following is a detailed analysis based on the latest technical data and market feedback:

 I. Core Technical Parameters and Performance

1. **Protection Capability*Chint NXR series thermal overload relays price*  

   - **Maximum Discharge Current (Imax)** : 40kA (8/20μs waveform), which can effectively discharge instantaneous overcurrent caused by direct lightning strikes or induced lightning.  

   - **Nominal Discharge Current (In)** : 20kA, meeting daily surge protection requirements.  

   - **Maximum Continuous Operating Voltage (Uc)** : 385V AC, compatible with 380V three-phase systems (such as TT and TN-S grounding systems).  

   - **Voltage Protection Level (Up)** : ≤1.8kV, ensuring precision equipment (e.g., PLCs, frequency converters) is protected from residual voltage damage.  

2. **Response Speed and Reliability*CHINT circuit breaker price*  

   - Response time <25 nanoseconds, enabling immediate activation of protection when a surge occurs.  

   - Adopts a collaborative work mode of zinc oxide varistors (MOV) and gas discharge tubes (GDT), featuring both high current handling capacity and low residual voltage characteristics.  

   - Equipped with a built-in thermal trip module, which automatically disconnects the circuit when components age or are overloaded to avoid short-circuit risks, and indicates deterioration status through a red window.  

3. **Certifications and Standards**  

   - Complies with international and domestic standards such as IEC 61643-11 and GB/T 18802.11, and has obtained CQC, CE, and CB certifications.  

   - Note: **UL certification has not been explicitly obtained**; users in the U.S. market need to confirm the applicability of local electrical regulations or choose other compatible models.  

 II. Application Scenarios and Installation Points

1. **Typical Applications**  

   - **Main distribution cabinets**: Used as secondary protection, it can achieve multi-level protection in conjunction with Class T1 SPDs (such as the NXU-I series). A minimum decoupling distance of ≥10m or additional decoupling inductors must be maintained.  

   - **Floor distribution boxes**: Directly installed at the incoming line end to protect downstream equipment from lightning and operational overvoltage.  

   - **Industrial equipment**: Suitable for equipment sensitive to voltage fluctuations, such as photovoltaic inverters and motor control centers (MCC).  

2. **Installation Specifications**  

   - **Wiring method**: The 4P structure needs to be connected to L1, L2, L3 phase lines, and neutral line (N). The cross-sectional area of the grounding wire should be ≥16mm², with a length ≤0.5m and kept short and straight.  

   - **Backup protection**: A 63A gG type fuse or Type B circuit breaker must be connected in series at the front end to prevent fire caused by SPD failure.  

   - **Dimensions**: Modular design with a width of 45mm (3 modules), compatible with TH35-7.5mm standard guide rails, requiring compact installation space.  

III. Market Feedback and Purchase Recommendations

1. **User Reviews**  

   Users report convenient installation and stable protection performance, especially reliable performance in thunderstorm-prone areas. Some users mentioned that "no equipment damage occurred after full configuration of the top-floor distribution box."  

2. **Price and Channels**  

   - **U.S. procurement**: For U.S. procurement, please contact via international business WhatsApp: 0086-13811255435. It is recommended to confirm UL compatibility and import tariffs in advance.  

3. **Alternative Solutions**  

   - If UL certification is required, consider Chint's NU6-II series (e.g., NU6-II 40/385 4P), which has similar technical parameters to the NXU-II but with a broader certification scope.  

   - For high-end needs, a T1+T2 combination scheme (such as the NXU-I+II series) can be selected to provide more comprehensive lightning protection.  

 IV. Precautions and Maintenance

1. **Environmental Requirements**  

   - Operating temperature range: -40℃~+70℃, humidity ≤95% (no condensation). Avoid installation in flammable, explosive, or corrosive environments.  

   - Altitude ≤2000m; derating is required for use in high-altitude areas.  

2. **Regular Inspection**  

   - Check the status indicator window before the annual thunderstorm season; if it is red, the module needs to be replaced.  

   - It is recommended to use professional equipment to test leakage current (Ile <100μA/pole) and voltage protection level to ensure performance meets standards.  

V. Summary

Chint NXU-II 40/385 has become a mainstream choice for surge protection in three-phase systems due to its high cost performance and stable performance. Its modular design, multi-level protection compatibility, and clear status indication make it particularly suitable for small and medium-sized projects. For U.S. users, it is recommended to prioritize confirming UL compliance or selecting alternative models, and purchase through authorized channels to ensure after-sales support. Strictly following decoupling and grounding specifications during installation can maximize its protection effectiveness.