- Product Overview
Chint NA8 series Air Circuit Breakers (ACB) are the fully upgraded version of the NA1 series, integrating high breaking capacity, zero arcing design, and intelligent protection. With a rated current range of 200A to 7500A, these breakers are applicable to 50Hz power distribution networks with rated voltages of 400V/690V. They are mainly used for power distribution and protecting lines and equipment against overload, sous-tension, court-circuit, single-phase grounding, and other faults. They are particularly suitable for scenarios with extreme environments, large-capacity power distribution, and high intelligent requirements.
- Paramètres techniques de base
2.1 Basic Electrical Parameters
| Paramètre | Spécification | Remarques |
| Rated Frame Current (Inm) | 1600UN, 2500UN, 3200UN, 4000UN, 7500UN | Covers the entire product series |
| Courant de fonctionnement nominal (Dans) | 200A~7500A | Different current ratings for each frame size |
| Tension de fonctionnement nominale (Ue) | AC 400V/690V | AC 690V for 3200/6300 specifications is under trial production |
| Tension d'isolation nominale (Interface utilisateur) | AC 1000V | Meets high-voltage insulation requirements |
| Rated Frequency | 50HZ | Standard industrial frequency |
| Numéro de pôle | 3P/4P | Rated current of the 4th pole is selectable |
| Breaking Capacity Class | N (Standard), H (High Breaking), HU (High-Voltage High Breaking) | H class is available for 2500A and above |
| Rated Ultimate Short-Circuit Breaking Capacity (ICU) | Up to 150kA | Icu=Ics=Icw/1s (for some specifications) |
| Rated Service Short-Circuit Breaking Capacity (Ics) | Up to 150kA | Same as Icu, with better protection coordination |
| Rated Short-Time Withstand Current (Icw) | Up to 150kA/1s | Meets stringent short-circuit impact requirements |
| Ambient Temperature for Use | -45°C ~ +70°C | Far superior to NA1 (-5°C~+40°C), adaptable to extreme environments |
| Pollution Degree | Class 3 | Complies with GB/T 14048.1 et CEI 60664-1 normes |
| Protection Degree | IP30 | Standard protection level, can be enhanced with accessories |
2.2 Detailed Parameters by Frame Size
NA8-1600 Series
| Courant nominal (UN) | 200 | 400 | 630 | 800 | 1000 | 1250 | 1600 |
| Capacité de coupure (ICU) | 55le(400V) | 55le(400V) | 55le(400V) | 55le(400V) | 55le(400V) | 55le(400V) | 55le(400V) |
| Rated Current of the 4th Pole | 200UN | 400UN | 630UN | 800UN | 1000UN | 1250UN | 1600UN |
NA8-2500/3200/4000 Series
| Frame Size | Rated Current Range | ICU(400V) | ICU(690V) |
| 2500UN | 1000~2500A | 100le(N)/125le(H) | 75le(N)/85le(H) |
| 3200UN | 1600~3200A | 100le(N)/125le(H) | 75le(N)/85le(H) |
| 4000UN | 2000~4000A | 100le(N)/125le(H) | 75le(N)/85le(H) |
NA8-7500 Series
| Courant nominal (UN) | 4000 | 5000 | 6300 | 7500 |
| ICU(400V) | 150le | 150le | 150le | 150le |
| ICU(690V) | 100le | 100le | 100le | 100le |
III. Breaking Characteristics and Arc Extinguishing System
- Zero Arcing Design: Optimized arc extinguishing chamber structure ensures no arc ejection from the breaker body during short-circuit breaking, improving safety.
- Contact System: Adopts new material and structural design, significantly extending electrical service life and reducing maintenance costs.
- Arc Extinguishing Medium: Air arc extinguishing, combined with special arc extinguishing grids, featuring fast breaking speed and strong breaking capacity.
- Temps de pause: Short-circuit breaking time ≤20ms, quickly cutting off faults and reducing equipment damage.
- Intelligent Protection Functions
The NA8 series is equipped with M/S/L-type intelligent controllers, providing comprehensive protection functions. Some models support advanced features such as 8-time fault recording, harmonic monitoring, and current fault early warning.
4.1 List of Protection Functions
| Type de protection | Description de la fonction | Caractéristiques de fonctionnement |
| Protection contre les surcharges (L) | Caractéristique à temps inverse, with three-stage protection (je>, je>>, je>>>) configurable | Complies with GB/T 14048.2 standard |
| Protection contre les courts-circuits (S/I) | Short-time delay (S) and instantaneous (je) protection, with configurable thresholds | Short-time delay adjustable from 0.1~0.4s, instantaneous with no delay |
| Ground Fault Protection (G) | Detects single-phase ground faults, with alarm or trip options available | High sensitivity and reliable operation |
| Protection contre les sous-tensions | Detects low line voltage, with configurable delayed operation | Prevents equipment damage under low voltage conditions |
| Overvoltage Protection | Detects high line voltage, with configurable delayed operation | Protects sensitive equipment |
| Phase Failure Protection | Detects three-phase current imbalance, preventing motor operation under phase loss conditions | Accurate operation, avoiding motor burnout |
| Harmonic Monitoring | Supported by some models, monitors grid harmonic content | Early warning of power quality issues |
| Fault Recording | Can record 8 fault events, including fault type, actuel, and time | Facilitates fault analysis and maintenance |
4.2 Types of Intelligent Controllers
| Controller Type | Scénario d'application | Functions |
| Type M | Basic protection requirements | Provides basic protection such as overload, court-circuit, and ground fault protection |
| Type S | Standard protection requirements | Adds functions like fault recording and parameter configuration |
| Type L | Advanced protection requirements | Supports harmonic monitoring, remote communication, and current fault early warning |
- Installation and Operation Characteristics
5.1 Méthodes d'installation
| Installation Type | Applicable Scenario | Caractéristiques |
| Fixed Type | Limited space, no frequent maintenance required | Simple installation and low cost |
| Drawout Type | Occasions requiring frequent inspection and replacement | Can be pulled out for maintenance without cutting off the main power supply, improving power supply continuity |
5.2 Wiring Methods
- Horizontal Connection: Standard wiring method, suitable for most scenarios.
- Vertical Connection: Saves installation space, ideal for compact distribution cabinet layouts.
- Mixed Connection: Flexible combination according to actual requirements.
5.3 Méthodes de fonctionnement
| Operation Type | Caractéristiques | Applicable Scenario |
| Manual Operation | Mechanical handle operation, no power supply required | Standby operation method, suitable for emergency situations |
| Electric Operation | Motor-driven, supports remote control | High automation level, suitable for unattended occasions |
| Stored-Energy Operation | Spring energy storage mechanism, fast closing and opening speed | Improves breaking reliability, suitable for frequent operation occasions |
- Mechanical and Environmental Characteristics
| Paramètre | Spécification | Remarques |
| Durée de vie mécanique | 10,000 opérations (drawout type), 20,000 opérations (fixed type) | Complies with national standards |
| Electrical Service Life | 1,000 opérations (at rated current) | Optimized contact system, extended service life |
| Operating Mechanism | Spring energy storage type | Fast closing and opening speed, not affected by power supply |
| Verrouillage mécanique | Optimized design, ensuring operation safety | Prevents misoperation and improves reliability |
| Secondary Connector | Improved design, reliable contact | Special for drawout installation, stable connection |
| Altitude | ≤2000m | Derating required when exceeding 2000m |
| Relative Humidity | ≤95% (at 25°C) | Adaptable to humid environments |
| Vibration and Shock Resistance | Complies with GB/T 14048.1 standard | Adaptable to industrial vibration environments |
VII. Accessory System
The NA8 series supports a rich range of accessories to meet different application requirements, and some accessories are compatible with the NA1 series.
7.1 Release Accessories
| Nom de l'accessoire | Fonction | Model Example |
| Déclenchement de dérivation | Remote control of breaker tripping | NA8-F |
| Undervoltage Release | Automatic tripping when line voltage is undervoltage | NA8-U |
| Overvoltage Release | Automatic tripping when line voltage is overvoltage | NA8-OV |
| Contact d'alarme | Sends alarm signal in case of faults | NA8-AL |
| Auxiliary Contact | Provides breaker status signal | NA8-AX (2 normalement ouvert, 2 normalement fermé) |
7.2 Operation Accessories
| Nom de l'accessoire | Fonction | Applicable Scenario |
| Electric Operating Mechanism | Motor-driven closing and opening | Automatic control systems |
| Rotary Operating Handle | Manual operation of the breaker | On-site operation |
| Locking Device | Locks breaker status to prevent misoperation | Occasions with high safety requirements |
| Padlocking Device | Allows padlocking to prevent unauthorized operation | Public places or critical equipment |
7.3 Protection Accessories
| Nom de l'accessoire | Fonction | Model Example |
| Leakage Current Transformer (LEC) | Detects leakage current, achieving residual current protection in conjunction with the controller | NA8-LEC |
| Residual Current Protection Module | Provides residual current protection function | NA8-RCM |
| Temperature Sensor | Monitors breaker temperature to prevent overheating | NA8-TS |
VIII. Selection Guide
8.1 Selection by Breaking Capacity
| Breaking Capacity Class | Applicable Scenario | Icu Value (400V) |
| Type N (Standard) | Conventional power distribution systems with short-circuit current ≤100kA | 55~100kA |
| Type H (High Breaking) | Occasions with large short-circuit current, par ex., near transformers | 125~150kA |
| Type HU (High-Voltage High Breaking) | 690V systems with large short-circuit current | 75~85kA |
8.2 Selection by Frame Size
| Frame Size | Rated Current Range | Applicable Scenario |
| 1600UN | 200~1600A | Small-sized factories, commercial buildings |
| 2500UN | 1000~2500A | Medium-sized factories, high-rise buildings |
| 3200UN | 1600~3200A | Large-sized factories, data centers |
| 4000UN | 2000~4000A | Extra-large factories, regional energy centers |
| 7500UN | 4000~7500A | Ultra-large factories, power grid hubs |
8.3 Selection by Installation Method
– Drawout Type: Recommended for occasions requiring frequent maintenance and breaker replacement, such as critical power distribution circuits.
– Fixed Type: Recommended for occasions with limited space and low maintenance frequency, such as general power distribution circuits.
- Core Differences from NA1 Series
Comparison Item NA8 Series NA1 Series Advantage Description Maximum Rated Current 7500UN 6300UN Covers larger capacity scenarios Capacité de coupure Up to 150kA Up to 100kA 50% improvement, more reliable short-circuit protection Adaptabilité environnementale -45°C~+70°C -5°C~+40°C Significantly enhanced adaptability to extreme environments Intelligence Level 8-time fault recording, harmonic monitoring, early warning Basic protection functions Comprehensive improvement in intelligence level Arc Extinguishing Technology Zero arcing design with optimized arc extinguishing chamber Standard arc extinguishing design Higher safety, reduced installation distance Contact System New material and structure Traditional design Extended electrical service life, lower maintenance cost - Recommended Application Scenarios
- Extreme Environment Scenarios: Frigid regions (-45°C), high-temperature environments (+70°C), high-humidity/salt spray environments (coastal areas/chemical industrial parks).
- Large-Capacity Power Distribution Scenarios: Ultra-large factories (steel/automotive/semiconductor), data centers/cloud computing facilities, regional energy centers.
- High Short-Circuit Risk Scenarios: Proximal ends of generators/transformers (short-circuit current 120-150kA), power grid interconnection nodes, industrial heavy-load starting occasions.
- High Intelligence Demand Scenarios: Predictive maintenance, smart grid integration, complex power distribution systems with enhanced safety interlocks.
- NA1 Upgrade Scenarios: Projects where the original NA1 system needs capacity expansion above 6300A, where environmental conditions are harsh, or where intelligence level needs to be improved.
- Ordering Information
Complete model designation of NA8 series products: NA8-Frame Size-Rated Current-Breaking Capacity/Pole Number-Installation Method-Controller Type
Exemple: NA8-7500-5000H/4P-Drawout Type-Type L Controller
XII. Executive Standards
The product complies with the following national and international standards:
- GB/T 14048.2-2018 Low-voltage Switchgear and Controlgear – Part 2: Circuit-breakers
- CEI 60947-2:2019 Low-voltage switchgear and controlgear – Part 2: Circuit-breakers
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