2CDS271334R0035 ABB ST201M-B3 MCB 15 kA 1P Type B 3 A UL 1077

Why Choose the ABB ST201M-B3 Miniature Circuit Breaker?

The ABB ST201M-B3 is a single-pole miniature circuit breaker / supplementary protector rated at 3 A with a Type B tripping characteristic. Designed for UL 1077 applications, it provides overcurrent protection for electrical equipment and internal circuits where supplementary protection is required.

With a 15 kA short-circuit interrupting rating, the ST201M-B3 combines compact modular construction with dependable thermal-magnetic protection. Its Type B characteristic provides rapid magnetic operation at relatively low multiples of rated current, making it particularly suitable for circuits with low inrush currents.

As part of ABB's modular circuit protection portfolio, the ST201M-B3 is designed for straightforward integration into industrial control equipment, machinery and other electrical assemblies. The 1-pole, 3 A configuration makes it well suited to protecting individual control, instrumentation and auxiliary circuits requiring UL 1077 supplementary overcurrent protection.

Key Advantages

• 3 A rated current for low-current control and auxiliary circuits.
• Type B tripping characteristic suited to loads with relatively low inrush current.
• 15 kA interrupting rating for robust supplementary circuit protection.
• Thermal-magnetic operating principle provides overload and short-circuit protection.
• Single-pole configuration for compact circuit protection.
• Modular construction supports efficient installation in electrical equipment.
• Designed as a UL 1077 supplementary protector.

Key Features

• ABB ST201M series supplementary protector.
• 1-pole configuration.
• 3 A rated current.
• B characteristic instantaneous tripping curve.
• 15 kA short-circuit interrupting rating.
• Thermal protection for sustained overload conditions.
• Magnetic protection for short-circuit conditions.
• Designed for UL 1077 supplementary protection applications.
• Suitable for modular industrial and OEM electrical assemblies.

Reliable Supplementary Overcurrent Protection

The ABB ST201M-B3 uses a thermal-magnetic operating mechanism to respond to two important overcurrent conditions. The thermal element responds to sustained overloads, while the magnetic mechanism provides rapid operation when a sufficiently high short-circuit current occurs.

Its Type B characteristic makes the ST201M-B3 particularly appropriate for circuits where high starting currents are not normally expected. As a UL 1077 supplementary protector, it is intended to provide additional overcurrent protection within equipment and appliances rather than serve as a substitute for required branch-circuit protection.

Typical Applications

• Industrial control circuits.
• Machine and automation control panels.
• Instrumentation circuits.
• Control power distribution.
• Auxiliary electrical circuits.
• OEM machinery and equipment.
• Electrical equipment requiring UL 1077 supplementary protection.