Chint Combined Switch NH5-20/4M04

 Chint Combined Switch NH5-20/4M04 is a switching device suitable for low-voltage power distribution and motor control scenarios.

I. Core Parameters and Structure

1. Model Meaning

NH5: Chint isolation switch series, supporting high short-circuit breaking capacity and reliable isolation function.

20: Rated current of 20A, suitable for small and medium-sized load circuits.

4M04:

  4P: 4-pole structure, capable of breaking three-phase live wires (L1, L2, L3) and neutral wire (N) simultaneously. It is applicable to three-phase four-wire systems and provides comprehensive circuit isolation and protection.

  M04: Tripping type code, presumably a thermal-magnetic release, which has both overload long-time delay protection (thermal element) and short-circuit instantaneous protection (electromagnetic element). It can realize two-stage protection without an external thermal relay.

2. Electrical Performance

Rated Voltage: AC 400V (complying with NH5 series standards).

Breaking Capacity: With reference to the characteristics of the NH5 series, the short-circuit breaking capacity is presumably 12Ie/1s (i.e., 240A short-time withstand current), which can handle sudden short-circuit faults.

Isolation Function: Complying with GB/T 14048.3 standard, it is equipped with clearly visible breaking contacts to ensure maintenance safety.

II. Application Scenarios

1. Power Distribution System

- Serving as the main switch of the terminal distribution box, it breaks the three-phase four-wire power supply and protects the lower-level circuits from overload and short-circuit damage.

- Suitable for power distribution systems of industrial equipment, commercial buildings, and residences, such as Motor Control Centers (MCC) and lighting distribution boxes.

2. Motor Control

- Directly controlling three-phase asynchronous motors with power ≤5.5kW (calculated based on the 20A rated current) to realize start-stop, commutation, and overload protection.

- When combined with contactors and thermal relays, it can form a complete motor control circuit to meet the needs of frequent operations.

3. Special Requirements

- The 4-pole design supports neutral wire protection, making it suitable for scenarios with three-phase unbalanced loads or harmonic interference (such as data centers and frequency conversion equipment) to prevent potential safety hazards caused by excessive neutral wire current.

III. Installation and Wiring

1. Installation Method

- Standard 35mm guide rail installation, compatible with DIN EN 60715 standard, saving space and facilitating maintenance.

2. Wiring Requirements

Incoming Terminal: Connect to three-phase power supply (L1, L2, L3) and neutral wire (N).

Outgoing Terminal: Connect to loads (such as motors and lighting equipment).

- Ensure firm wiring to avoid heating or poor contact caused by loose connections.

IV. Certification and Reliability

1. Certification Standards

- Complying with GB/T 14048.3 (Low-Voltage Switchgear and Controlgear) and IEC 60947-3 international standards, and has passed CCC certification to ensure product quality and safety.

2. Environmental Adaptability

- Operating temperature range: -5℃ ~ +40℃, adaptable to most industrial and civil environments.

- Protection class: IP20 (preventing the intrusion of solid foreign objects larger than 12mm), and it needs to be used with a distribution box to improve protection performance.

V. Model Selection and Alternative Solutions

1. Comparison with Similar Products

Chint HZ5 Series: Both are combined switches, but the NH5 series has higher breaking capacity and is suitable for scenarios with stricter requirements for short-circuit protection.

Schneider NSX Series: If higher breaking capacity (e.g., above 50kA) or intelligent tripping function (electronic release) is required, upgrading to Schneider products can be considered, but the cost will increase significantly.

2. Recommendations for Alternative Models

- If a higher rated current (e.g., 63A) is needed, NH5-63/4M04 can be selected; if a smaller current (e.g., 10A) is needed, NH5-10/4M04 can be selected.

- For motor control, it can be matched with Chint CJX2 series contactors and JR36 series thermal relays to achieve more accurate protection.

VI. Precautions

1. Load Matching

- Ensure that the load current does not exceed 20A. Especially when the motor starts, the instantaneous inrush current (usually 5-7 times the rated current) should be considered to avoid false tripping.

2. Maintenance and Inspection

- Regularly check the wear of contacts. If ablation or poor contact is found, the switch should be replaced in a timely manner.

- The operating characteristics of the thermal-magnetic release are affected by the ambient temperature; long-term use in high-temperature environments should be avoided.

3. Installation Specifications

- Conduct wiring in strict accordance with the instruction manual to avoid reverse connection of live wires and neutral wires or short circuits.

- The neutral terminal of the 4-pole switch must be reliably connected and must not be left floating.

VII. Price and Procurement

Reference Price: According to the market situation, the unit price of NH5-20/4M04 is approximately 150-200 RMB. For specific quotations, please contact via WhatsApp: 0086-13811255435.

Summary

Chint Combined Switch NH5-20/4M04 is a cost-effective 4-pole isolation switch that integrates overload protection, short-circuit protection, and circuit isolation functions. It is suitable for small and medium-sized power distribution and motor control scenarios. Its thermal-magnetic release and 4-pole design provide reliable safety guarantees for three-phase four-wire systems, making it an ideal choice for industrial and civil fields. When selecting the model, comprehensive consideration should be given to the actual load requirements and installation environment, and electrical installation specifications should be followed to ensure the stable operation of the system.