Why Choose the ABB S203MT-K20NA Miniature Circuit Breaker?
The ABB S203MT-K20NA is a compact and reliable miniature circuit breaker (MCB) designed to provide overload and short-circuit protection in low-voltage electrical installations. As part of the ABB S200MT miniature circuit breaker range, it is developed for demanding industrial, traction and railway applications where dependable circuit protection, compact installation and long service life are essential.
This circuit breaker features a K curve tripping characteristic, making it suitable for circuits with higher inrush currents such as motors, transformers, solenoids and other inductive loads. Its current limiting design helps reduce fault energy, supporting safer operation and improved protection for cables, switchgear and connected equipment.
With a rated current of 20 A and a 3-pole plus neutral configuration, the ABB S203MT-K20NA is ideal for three-phase systems where the neutral conductor must switch together with the protected phases. Its DIN rail mounting design enables straightforward installation inside control panels, distribution boards, switchgear cabinets and machinery enclosures.
Key Advantages
- Compact miniature circuit breaker for circuit protection.
- 20 A rated current for low-voltage electrical circuits.
- 3-pole plus neutral configuration for three-phase systems with switched neutral.
- K curve tripping characteristic for circuits with higher inrush currents.
- 10 kA breaking capacity for dependable short-circuit protection.
- DIN rail mounting for fast installation in electrical enclosures.
Key Features
- ABB S200MT miniature circuit breaker series.
- 20 A nominal current rating.
- 3 protected poles plus neutral.
- K type tripping curve for inductive loads.
- Thermal tripping mechanism for overload protection.
- Electromechanical tripping mechanism for short-circuit protection.
- Current limiting class 3 performance.
- Compatible with ABB System pro M compact accessories.
Miniature circuit breakers such as the ABB S203MT-K20NA protect electrical circuits by automatically disconnecting the supply when overload or short-circuit faults occur. This helps prevent cable damage, equipment failure and unsafe fault conditions in control and distribution systems.
The K curve characteristic allows higher transient inrush currents while still providing dependable short-circuit protection. This makes the S203MT-K20NA suitable for circuits supplying motors, transformers, contactor coils and other inductive equipment where nuisance tripping should be avoided during normal start-up conditions.
Typical Applications
- Industrial control panels and automation systems.
- Railway and traction electrical installations.
- Three-phase circuits requiring switched neutral protection.
- Distribution boards and switchgear assemblies.
- Motor, transformer and inductive load circuits.
- Machine building and OEM electrical systems.
