Chint Household Contactor NCH8-20/20

The Chint Household Contactor NCH8-20/20 is a modular contactor specifically designed for residential and small - commercial scenarios. It is mainly used to control low - inductance loads or motor equipment.

 I. Model and Parameter Interpretation

1. Model Meaning

NCH8: It is the series name, representing Chint's household contactor product line.

20: The rated current of the main contact is 20A, which is suitable for resistive loads (such as electric heating equipment and lamps). In this case, the maximum power can reach 220V × 20A = 4.4kW.

/20: The contact configuration is 2 sets of Normally Open (NO) + 0 sets of Normally Closed (NC), which means it only supports the on - off control of a single circuit.

Coil Voltage: It supports 220/230V AC by default, and a 24V AC version is also available (e.g., NCH8-20/20 24V).

2. Key Parameters

Pole Number: 2P (single - phase), suitable for 220V single - phase circuits.

Application Category: AC - 1 (resistive loads), AC - 7a (household motor loads). When controlling motors, the capacity needs to be derated to approximately 9A.

Mechanical Life: ≥ 1,000,000 times; Electrical Life: ≥ 100,000 times, featuring strong durability.

Certification: It has passed the CCC certification and complies with the GB/T 17885 and IEC 61095 standards.

 II. Application Scenarios

1. Home Automation

- It controls the start and stop of high - power electrical appliances (such as air conditioners, electric water heaters, and heat pumps) to realize timing or remote control.

- It is matched with smart switches or PLCs to build a smart home system (such as light linkage and curtain control).

2. Small - Commercial Equipment

- It controls the circuit on - off of hotel card - operated power supply systems, small water pumps, and commercial kitchen appliances (such as coffee machines and ovens).

- It replaces traditional relays, simplifies the layout of distribution boxes, and improves space utilization.

 III. Product Features

1. Mute Design

- It adopts a direct - acting structure, and the pull - in noise is lower than 20dB, making it suitable for places sensitive to environmental noise (such as bedrooms and hospitals).

2. Convenient Installation

- It supports the installation of TH35 - 7.5mm standard guide rails, which can be quickly clamped into the distribution box, saving installation time.

- The labels on the terminal blocks at the back are clear (L1/L2 are connected to the power supply, T1/T2 are connected to the load, and A1/A2 are connected to the control signal), and it is compatible with wires with a cross - sectional area of less than 2.5mm².

3. Safety Protection

- The shell is made of flame - retardant materials, with an IP20 protection rating to prevent accidental electric shock.

- Each product is attached with an independent anti - counterfeiting code, and the authenticity can be verified by scanning the code.

 IV. Selection and Usage Suggestions

1. Load Matching

Resistive Loads: Select directly according to the rated current of 20A, for example, when controlling electric heaters with a total power of ≤ 4.4kW.

Inductive Loads (such as motors): The capacity needs to be derated to approximately 9A, for example, when controlling single - phase water pumps with a power of less than 1.5kW.

Lighting Control: You can refer to the official selection table. For example, the NCH8 - 20/20 can support a maximum of 20 60W incandescent lamps or 17 35W fluorescent lamps (with parallel compensation).

2. Alternative Model Reference

- If more contacts are needed, you can choose NCH8 - 20/31 (3NO + 1NC) or NCH8 - 20/22 (2NO + 2NC).

- For manual operation scenarios, you can consider the NCH8 - M series (such as NCH8 - 20M/20), which supports temporary on - off control via a handle.

3. Price and Purchase

- The reference market price is about 49.73 RMB per unit (for the 220V version), and discounts are available for bulk purchases.

- It is recommended to purchase via Chint's WhatsApp: 0086 - 13811255435 to ensure product quality and after - sales service.

 V. Installation and Wiring Steps

1. Preparation of Tools

- Screwdriver, wire stripper, multimeter, and insulating tape.

2. Guide Rail Installation

- Fix the 35mm guide rail in the distribution box to ensure stability.

- Align with the card slot at the back of the contactor and press down until the buckle is locked.

3. Circuit Connection

Main Circuit: Connect L1/L2 to the live wire and neutral wire of the 220V power supply, and connect T1/T2 to the load (such as the outdoor unit of an air conditioner).

Control Circuit: Connect A1/A2 to the control signal (such as the output of a switch or timer). For the 24V version, an additional transformer needs to be configured.

4. Testing and Debugging

- Before power - on, check whether the wiring is firm, and use a multimeter to measure the coil resistance (the 220V version has a resistance of approximately 1.5kΩ).

- Short - circuit A1/A2, observe whether the contactor pulls in normally and whether the contact actions are synchronized.

 VI. Precautions

1. Heat Dissipation Requirements

- When multiple contactors are installed densely, spacing pieces (about 18mm) need to be reserved to avoid overheating and capacity reduction.

- When the ambient temperature exceeds 40℃, it is recommended to use the contactor with derated capacity (for example, the 20A model can only carry 16A at 50℃).

2. Short - Circuit Protection

- A small circuit breaker (such as DZ47 - 63) must be connected in series, and the breaking capacity should be ≥ 6kA to prevent equipment damage due to faults.

3. Regular Maintenance

- Check the contact wear condition every year. If the contact thickness is reduced by 1/3, it should be replaced in a timely manner.

- Clean the dust on the shell to ensure that the heat dissipation holes are unobstructed, so as to avoid the decline of insulation performance caused by dust accumulation.

Through the above information, users can fully understand the characteristics and applications of the NCH8 - 20/20, select the product reasonably, use it safely, and realize the efficient control of residential or small - commercial equipment.