Description
1. Product Overview
ABB NSB204‑502W, part‑no. 3AXD50000032687, is a 4‑pole miniature circuit‑breaker from the ABB NSB200 series, a terminal protection component dedicated for industrial and civil power‑distribution systems. Built on ABB’s mature low‑voltage distribution technology, it delivers accurate overload and short‑circuit protection, featuring compact structure, high breaking capacity and reliable performance. It can rapidly cut off fault current upon circuit abnormalities so as to safeguard downstream electrical equipment and wiring. Suitable for building power distribution, industrial automation, complete electric‑control assemblies and terminal power loops, it serves as a fundamental core component for circuit protection, load control and switching‑on/off in low‑voltage distribution systems.
2. Core Functions
Reliable Switching Control for Full Circuit: Adopts a complete 4‑pole circuit design to realize synchronous closing and opening of 3‑phase 4‑wire distribution loops. It adapts to both balanced and unbalanced 3‑phase loads and meets switching‑on/off requirements of multi‑loop distribution in industrial and building projects.
Dual‑Protection against Electrical Faults: Built‑in thermal‑magnetic tripping mechanism integrating time‑delay overload protection and instantaneous short‑circuit protection. It trips with delay under mild overload and breaks instantly during sudden short‑circuit faults, comprehensively preventing risks such as cable burnout, equipment breakdown and electrical fire hazards.
Excellent Short‑circuit Breaking Performance: Features a high‑standard rated breaking capacity, which quickly extinguishes fault arcs, interrupts short‑circuit current and withstands instantaneous high‑current surges, making it suitable for complex operating conditions with frequent load fluctuations and transient overloads.
Stable and Accurate Tripping Characteristics: Its tripping curve is precise and consistent with minor threshold errors. It can clearly distinguish normal load fluctuations from real faults to avoid nuisance tripping or failure to trip, ensuring continuous and stable operation of the power‑distribution system.
Modular Integrated Structure: Standard DIN‑rail mounting, compact footprint and easy installation and removal. It fits standard distribution cabinets, facilitates quick replacement and system expansion, and offers great adaptability.
- Durable Industrial‑grade Operation: Constructed with high‑strength flame‑retardant housing and wear‑resistant internal contacts. It is ageing‑resistant, temperature‑rise‑resistant and arc‑resistant, supporting long‑term continuous energization and frequent switching‑on/off in low‑voltage distribution circuits for extended service life.
3. Technical Specifications
| Parameter Item | Technical Specification |
|---|---|
| Product Model | NSB204‑502W |
| Material Code | 3AXD50000032687 |
| Product Type | 4‑Pole Miniature Circuit‑Breaker |
| Number of Poles | 4P (Four‑pole) |
| Rated Voltage | AC 400 V, industrial low‑voltage standard |
| Applicable Power‑supply System | 3‑phase 4‑wire distribution system |
| Protection Mode | Thermal‑magnetic tripping (Overload protection + Short‑circuit protection) |
| Mounting Method | Standard DIN‑rail mounting |
| Housing Features | Flame‑retardant, high‑temperature‑resistant, ageing‑resistant industrial material |
| Operating Temperature | -25℃～+70℃ |
| Core Characteristics | Precise protection, high breaking‑capacity, low nuisance‑trip rate, easy installation |
4. Working Principle
The ABB NSB204‑502W circuit‑breaker implements automatic fault protection and circuit switching based on dual tripping principles of thermal effect and electromagnetic induction. During normal operation, current flows steadily through internal contacts and tripping assemblies while the breaker remains closed to supply power to loads.
When mild overload occurs and current continuously exceeds the rated value, the bimetallic strip deforms under heat and triggers time‑delay tripping via mechanical transmission for overload protection, preventing cable heating and ageing caused by long‑term overload. In case of short‑circuit faults with instantaneous high‑current surges, the electromagnetic coil generates strong magnetic force instantly to actuate immediate tripping, rapidly isolating the faulty circuit and containing fault escalation. It maintains continuous conduction under normal loads and precise disconnection during faults to guarantee safe and stable operation of low‑voltage distribution systems.
5. System Architecture Compatibility
As a universal 4‑pole low‑voltage circuit‑breaker, this product is widely compatible with conventional low‑voltage distribution architectures. It can be directly deployed in 3‑phase 4‑wire industrial distribution systems, building lighting and power supply circuits, and seamlessly cooperates with contactors, relays, air‑switches, PLC automatic‑control systems and complete distribution‑cabinet assemblies.
With universal rail‑mount dimensions, it fits standard industrial power cabinets and electric‑control enclosures, supporting equipment retrofitting and distribution‑loop expansion. Its protection and control circuits fully comply with civil and industrial low‑voltage power‑supply standards, so it can be put into service quickly without modification to existing wiring or system architecture.
6. Application Scenarios
This product is widely used for low‑voltage distribution protection in industrial, building and municipal projects. In industrial sectors, it provides overload and short‑circuit protection for automation production‑lines, workshop power cabinets, complete electric‑control assemblies and terminal circuits of medium‑and‑small‑sized generator‑sets. In building projects, it performs power‑supply protection and circuit control for 3‑phase 4‑wire distribution systems in commercial buildings, factory office buildings and supporting equipment rooms.
It is also suitable for water‑treatment facilities, auxiliary power‑distribution for new‑energy projects, mine terminal power loops and municipal electrical installations. Acting as a core terminal protection device in low‑voltage distribution networks, it ensures safe and stable operation of cables, terminal equipment and the whole distribution system.
