Product Specifications
Technical Parameters
| Parameter | Value |
|---|---|
| Product Model | NB8-125 |
| Rated Current | 80 A, 100 A, 125 A |
| Rated Voltage | AC 230/400 V |
| Rated Frequency | 50 Hz |
| Number of Poles | 1P, 2P, 3P, 4P |
| Mechanical Life | 20,000 operations |
| Electrical Life | 6,000 operations; 4,000 operations for the 125 A version |
| Rated Short-Circuit Breaking Capacity | 10,000 A |
| Service Short-Circuit Breaking Capacity | 7,500 A |
| Rated Insulation Voltage | 630 V |
| Rated Impulse Withstand Voltage | 6 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 | 25 mm² |
| Maximum Conductor Cross-Section | 50 mm² |
| Standard Tightening Torque | 3.5 N·m |
| Conductor Insertion Depth | 14 mm |
| Reference Temperature | 40°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 | C curve: 6.4In–9.6In; D curve: 9.6In–14.4In |
| Enclosure Flame-Retardant Rating | V-0 |
| Incoming Wiring Direction | Top or bottom |
| Pollution Degree | 3 |
| Degree of Protection | IP20B when directly installed; IP40B when installed in a distribution enclosure |
| Optional Accessories | S9, V9, XF9, XF9J, OVT-1, OUVT-1 |
尺寸图
Product Overview
The NB8-125 series miniature circuit breaker is mainly designed for AC 50 Hz low-voltage distribution circuits with a rated voltage up to 400 V and a rated current up to 125 A. It is widely used in main and branch distribution systems in commercial office buildings, residential properties, and general industrial facilities. When an overload or short-circuit fault occurs, the circuit breaker automatically interrupts the circuit to protect distribution lines and connected electrical equipment. Under normal operating conditions, it may also be used for infrequent switching and isolation of circuits. The NB8-125 series is available in rated currents of 80 A, 100 A, and 125 A, with 1P, 2P, 3P, and 4P configurations. It can therefore meet the requirements of both single-phase and three-phase low-voltage distribution systems. The rated short-circuit breaking capacity is 10,000 A, while the service short-circuit breaking capacity is 7,500 A, making the product suitable for applications requiring higher current-carrying and fault-interruption performance. The circuit breaker uses a thermal-magnetic tripping mechanism and is available with C-curve and D-curve electromagnetic tripping characteristics. The C curve is suitable for lighting, distribution circuits, and general inductive loads, while the D curve is intended for motors, transformers, and other equipment with high starting currents. The NB8-125 supports both top and bottom incoming wiring and features a compact structure, large wiring capacity, reliable operation, and convenient installation and maintenance. Optional accessories can be added for auxiliary indication, alarm signaling, shunt tripping, overvoltage protection, and undervoltage protection.
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