Chint DZ108-20/211 is a molded case circuit breaker (MCCB)

Chint DZ108-20/211 is a molded case circuit breaker (MCCB) specifically designed for motor protection. It is mainly used in circuits with an AC frequency of 50Hz and a rated voltage up to 380V, providing overload and short-circuit protection, as well as supporting infrequent starting of motors and line switching. The following is a detailed analysis of its core technical parameters and application scenarios:

 I. Model Interpretation and Basic Parameters

- Model Composition:

  - **DZ108**: Series code, representing a molded case circuit breaker specifically designed for motor protection.

  - **20**: Frame current rating is 20A, which refers to the maximum continuous current that the circuit breaker can safely carry.

  - **211**: Auxiliary contact configuration is 1 Normally Open (NO) + 1 Normally Closed (NC), used for signal feedback or control circuit expansion.

- Rated Parameters:

  - Rated insulation voltage: 660V, suitable for insulation requirements in high-voltage environments.

  - Rated operating voltage: 380V AC, in line with industrial power distribution standards in China and most other countries.

  - Pole number: 3 poles, applicable to three-phase motor control circuits.

  - Tripping characteristics:

    - **Overload protection**: Bimetallic strip inverse-time release with temperature compensation function. It can automatically adjust the tripping time according to the degree of current overload to avoid false tripping.

    - **Short-circuit protection**: Electromagnetic instantaneous release. When the short-circuit current reaches 10 times the rated current, it can quickly break the circuit within 0.2 seconds.

  - Breaking capacity: At a voltage of 380V, the rated short-circuit breaking capacity is 1.5kA, which meets the short-circuit protection requirements of general industrial environments.

II. Application Scenarios and Installation Characteristics

1. Core Applications:

  - **Motor protection**: Suitable for three-phase motors (380V) with a power ≤ 10kW. It can replace the traditional combination of thermal overload relay and fuse, providing integrated overload and short-circuit protection.

  - **Power distribution line protection**: Used as terminal power distribution equipment to protect branch lines from overload and short circuits, such as in distribution boxes of factory workshops and commercial buildings.

  - **Infrequent operation**: Supports direct starting of motors and line switching, with an operating frequency ≤ 30 times per hour.

 2. Installation and Wiring:

  - **DIN rail mounting**: Equipped with a standard 35mm DIN rail clamp as standard, which can be quickly fixed in the distribution box, saving space and facilitating maintenance.

  - **Front-panel wiring**: Adopts screw-type terminal blocks, supporting wire cross-sectional areas of 1.5-6mm². It is necessary to ensure that the wiring is secure to avoid heat generation.

  - **Wiring example**: In an inching control circuit, the normally open contact of the circuit breaker can be connected in series with the contactor coil to realize temporary start-stop control of the motor.

 3. Auxiliary Functions:

  - **Signal feedback**: The 1NO + 1NC auxiliary contacts can be connected to a PLC or indicator light to monitor the status of the circuit breaker (e.g., closed, tripped) in real time.

  - **Environmental adaptability**: Operating temperature range is -5℃ ~ +40℃, with an IP20 protection rating, which can prevent the intrusion of solid foreign objects.

III. Selection and Usage Precautions

1. Key Selection Points:

  - **Rated current matching**: Select the release setting range according to the rated current of the motor. For example, a motor with a rated current of 8A should be matched with DZ108-20/211 (setting range: 5-8A).

  - **Pole number selection**: Three-pole models are required for three-phase motors, while two-pole models (e.g., DZ108-20/210) can be selected for single-phase loads.

  - **Certification requirements**: This model complies with the GB/T 14048.2 standard, but has not clearly obtained UL certification. If used in the North American market, it is necessary to confirm whether there is a corresponding cULus-certified model (e.g., Chint NXB series).

2. Usage Recommendations:

  - **Regular maintenance**: Check the tightness of the terminal blocks every 6 months and remove dust to ensure good heat dissipation.

  - **Troubleshooting**: If frequent tripping occurs, it is necessary to check whether the motor is overloaded, whether the wiring is loose, or whether the short-circuit fault has not been completely eliminated.

  - **Alternative solutions**: If higher breaking capacity (e.g., above 10kA) is required, Chint NM1 series molded case circuit breakers can be selected; if leakage protection is needed, it can be matched with DZL18 series residual current circuit breakers.

IV. Market Supply and Price Reference

 - Supply Channels:

  - In the Chinese market, this model can be purchased via WhatsApp: 0086-13811255435. The packaging specification is usually 5 pieces per box, with a unit price of approximately 45-60 RMB per piece.

  - **North American market**: Currently, no UL certification information for DZ108-20/211 has been found. It is recommended to consult via WhatsApp: 0086-13811255435.

 V. Comparison with Other Models

Chint DZ108-20/211 is a cost-effective motor protection circuit breaker, especially suitable for small and medium-sized motor control and terminal power distribution scenarios. Its integrated design, DIN rail mounting, and temperature compensation function significantly improve installation efficiency and reliability. When used in international markets such as North America, attention should be paid to certification requirements, and compatible models should be selected if necessary. For higher performance needs, an upgrade to Chint NM1 series or products of other brands can be considered.