ABB S203MT-K0.5NAH10 S200MT miniature circuit breaker, a 3P+N 0.5 A K curve MCB designed for traction, railway, industrial and low-current circuit protection applications.
The ABB S203MT-K0.5NAH10 is a specialist 3P+N miniature circuit breaker (MCB) from the ABB S200MT traction and railway series. Designed for demanding transport, industrial and control panel environments, it provides reliable overload and short circuit protection for low-current three-phase circuits with neutral switching.
Featuring a K tripping characteristic, the S203MT-K0.5NAH10 is suitable for circuits with higher inrush currents, including control transformers, power supplies, auxiliary equipment and specialist traction applications. Its current limiting design helps reduce fault energy, supporting safer operation and improved protection of connected electrical equipment.
With a 0.5 A rated current, 3P+N configuration and compact DIN rail mounted construction, this ABB miniature circuit breaker is ideal for low-current protection in railway systems, control cabinets, automation panels and industrial distribution assemblies. This product may be supplied or referenced under newer equivalent ABB S203MT-K0.5NA part numbering.
Miniature circuit breakers such as the ABB S203MT-K0.5NAH10 protect electrical installations by disconnecting circuits during overload or short circuit conditions. The delayed thermal mechanism responds to sustained overloads, while the electromechanical magnetic mechanism provides rapid tripping during short circuit faults.
The K curve characteristic is useful where connected equipment can produce short-duration inrush currents during energisation. This makes the S203MT-K0.5NAH10 suitable for low-current auxiliary systems, control transformers, power supplies and specialist railway or industrial applications where dependable protection is essential.
| Current | 0.5 A |
|---|---|
| Phase | Three Phase |
| Manufacturer | ABB |
| Series | S200MT |
| Model | S203MT-K0.5NAH10 |
| Current equivalent | S203MT-K0.5NA |
| Product type | Miniature Circuit Breaker (MCB) |
| Rated current | 0.5 A |
| Poles | 3P+N |
| Protected poles | 3 |
| Trip characteristic | K Curve |
| Rated operational voltage | 440 V AC |
| Frequency | 50 / 60 Hz |
| Breaking capacity | 15 kA at 230 / 400 V AC |
| Rated service short circuit breaking capacity | 11.2 kA |
| Current limiting class | 3 |
| Protection rating | IP20 |
| Mounting type | DIN rail |
| Terminal type | Screw terminals |
| Mechanical endurance | 20,000 operating cycles |
| Dimensions (H × W × D) | approx. 88 × 70 × 69 mm |
| Standards | IEC/EN 60898-1, IEC/EN 60947-2 |
The ABB S203MT-K0.5NAH10 is used to protect low-current three-phase circuits against overloads and short circuits in traction, railway, industrial and control panel applications.
A K curve MCB is designed for circuits with higher inrush currents, making it suitable for transformers, power supplies and inductive loads.
The S203MT-K0.5NAH10 has a 3P+N configuration, with three protected poles and a switched neutral.
The ABB S203MT-K0.5NAH10 has a rated current of 0.5 A.
This part may be referenced as an older or superseded version, with S203MT-K0.5NA commonly used as the current equivalent. Please check availability before ordering.
ABB S200MT miniature circuit breakers are trusted by electrical engineers, panel builders and transport system manufacturers for dependable circuit protection, compact installation and reliable performance in demanding electrical environments.
● Service Agreements
Credit Accounts
Our service agreements are built to support long term procurement relationships. By working closely with engineering teams and procurement departments, we help streamline purchasing processes while ensuring consistent access to critical components and sourcing support when it matters most.
● frequently asked questions
At Led Controls Ltd we help engineers source the right automation and control gear with confidence. below are quick answers to what we are asked most often.
We supply all leading manfacturers in our industry. we offer next day delivery on most poplour products.
Your content goes here. Edit or remove this text inline or in the module Content settings. You can also style every aspect of this content in the module Design settings and even apply custom CSS to this text in the module Advanced settings.
Your content goes here. Edit or remove this text inline or in the module Content settings. You can also style every aspect of this content in the module Design settings and even apply custom CSS to this text in the module Advanced settings.
Your content goes here. Edit or remove this text inline or in the module Content settings. You can also style every aspect of this content in the module Design settings and even apply custom CSS to this text in the module Advanced settings.
Your content goes here. Edit or remove this text inline or in the module Content settings. You can also style every aspect of this content in the module Design settings and even apply custom CSS to this text in the module Advanced settings.
● latest blog
LED Controls is a specialist distributor of factory automation and industrial controls, supplying OEMs, machine builders, panel builders and end users throughout the UK and worldwide. As a trusted UK distributor for many of the world’s leading automation manufacturers, we provide industrial control products, technical expertise and bespoke automation solutions backed by outstanding customer service.
2025 has been a big year for LED Controls, and our blog has expanded accordingly. We've covered a wide range of topics across industrial control and factory automation this year. From core technology explainers and new product releases to panel building best practice...
2025 has been a big year for LED Controls, and our blog has expanded accordingly. We've covered a wide range of topics across industrial control and factory automation this year. From core technology explainers and new product releases to panel building best practice...