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Chint
NB8-40 Miniature Circuit Breaker
The NB8-40 miniature circuit breaker is designed for AC 50 Hz terminal distribution circuits with a rated voltage of 230 V and a rated current up to 40 A. It provides reliable overload and short-circuit protection for commercial buildings, residential properties, and general industrial applications.
- Brand
- Chint
- Model
- NB8-40
- Product category
- Miniature Circuit Breaker
Product overview
The NB8-40 miniature circuit breaker is mainly designed for AC 50 Hz terminal distribution circuits with a rated voltage of 230 V and a rated current up to 40 A. It is widely used in commercial office buildings, residential properties, and general industrial applications.
The product adopts a 1P+N configuration and provides reliable overload and short-circuit protection for electrical circuits and connected equipment. Its rated short-circuit breaking capacity and service short-circuit breaking capacity are both 6,000 A, making it suitable for common terminal distribution systems.
The NB8-40 is available with B-curve and C-curve electromagnetic tripping characteristics. The B curve is suitable for resistive loads and circuits with low inrush current, while the C curve is suitable for lighting, socket circuits, and general inductive loads.
The circuit breaker is designed for installation on a TH35-7.5 standard DIN rail and supports both top and bottom incoming wiring. It uses a thermal-magnetic tripping mechanism and offers compact construction, convenient installation, reliable operation, and a long service life.
A range of optional accessories can be combined with the circuit breaker to provide extended functions such as status indication, remote operation, overvoltage protection, and undervoltage protection.
Specifications
Technical Parameters
| Parameter | Value |
|---|---|
| Product Model | NB8-40 |
| Rated Current | 1 A, 2 A, 3 A, 4 A, 6 A, 10 A, 16 A, 20 A, 25 A, 32 A, 40 A |
| Rated Voltage | 230 V |
| Rated Frequency | 50 Hz |
| Number of Poles | 1P+N |
| Mechanical Life | 20,000 operations |
| Electrical Life | 10,000 operations |
| Rated Short-Circuit Breaking Capacity | 6,000 A |
| Service Short-Circuit Breaking Capacity | 6,000 A |
| Rated Insulation Voltage | 500 V |
| Rated Impulse Withstand Voltage | 4 kV |
| Dielectric Test Voltage | 2,000 V, 50 Hz, 1 minute |
| Resistance to Damp Heat | 28-cycle test |
| Vibration Resistance | Suitable for locations without significant vibration or impact |
| Terminal Type | Pillar terminal |
| Minimum Conductor Cross-Section | 1 mm² |
| Maximum Conductor Cross-Section | 16 mm² |
| Standard Tightening Torque | 1.2 N·m |
| Maximum Permissible Torque | 2 N·m |
| Conductor Insertion Depth | 10 mm |
| Reference Temperature | 30°C |
| Operating Temperature | -35°C to +70°C |
| Storage Temperature | -35°C to +85°C |
| Maximum Operating Altitude | 2,000 m |
| Tripping Type | Thermal-magnetic trip |
| Electromagnetic Trip Curve | B curve: 3In–5In; C curve: 5In–10In |
| Enclosure Flame-Retardant Rating | V-0 |
| Incoming Wiring Direction | Top or bottom |
| Mounting Method | TH35-7.5 standard DIN rail |
| Pollution Degree | 2 |
| Degree of Protection | IP20B when directly installed; IP40B when installed in a distribution enclosure |
| Optional Accessories | S9, V9, XF9, XF9J, OVT-1, OUVT-1 |
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