2CDS271334R0041 ABB ST201M-D4 MCB 15 kA 1P Type D 4 A UL 1077

Why Choose the ABB ST201M-D4 Miniature Circuit Breaker?

The ABB ST201M-D4 is a single-pole miniature circuit breaker / supplementary protector rated at 4 A with a Type D tripping characteristic. Designed for UL 1077 applications, it provides supplementary overcurrent protection for electrical equipment and internal circuits where higher transient or starting currents may occur.

With a 15 kA short-circuit interrupting rating, the ST201M-D4 combines compact modular construction with thermal-magnetic protection against overload and short-circuit conditions. Its Type D characteristic is particularly suited to appropriate loads with comparatively high inrush currents, helping avoid unnecessary operation during normal equipment start-up.

As part of ABB's modular circuit protection portfolio, the ST201M-D4 is suitable for integration into industrial control equipment, machinery and OEM electrical assemblies. The 1-pole, 4 A configuration provides focused supplementary protection for individual circuits while retaining the convenience of a modular protective device.

Key Advantages

• 4 A rated current for low-current equipment and control circuits.
• Type D tripping characteristic suited to appropriate loads with higher inrush currents.
• 15 kA short-circuit interrupting rating.
• Thermal-magnetic operation provides both overload and short-circuit protection.
• Single-pole configuration supports compact circuit protection layouts.
• Modular construction simplifies integration into electrical equipment.
• Designed for UL 1077 supplementary protection applications.

Key Features

• ABB ST201M series supplementary protector.
• 1-pole configuration.
• 4 A rated current.
• Type D tripping characteristic.
• 15 kA short-circuit interrupting rating.
• Thermal protection for sustained overload conditions.
• Magnetic operation for short-circuit conditions.
• Suitable for circuits subject to comparatively high starting or transient currents.
• Designed for UL 1077 applications.

Reliable Protection for Higher-Inrush Circuits

The ABB ST201M-D4 uses thermal-magnetic protection to respond to both sustained overloads and short-circuit conditions. Its thermal element reacts to prolonged overcurrent, while the magnetic mechanism provides rapid operation when fault current rises sufficiently above the rated current.

The Type D characteristic provides greater tolerance of short-duration starting currents than lower-inrush trip characteristics, making it useful for appropriately engineered circuits containing equipment such as transformers, solenoids or other inductive loads. As a UL 1077 supplementary protector, the ST201M-D4 is intended for supplementary protection within equipment and does not replace required branch-circuit protection.

Typical Applications

• Industrial control circuits.
• Machine and automation control panels.
• Transformer auxiliary circuits.
• Solenoid and inductive-load circuits.
• OEM machinery and electrical equipment.
• Control power distribution.
• Equipment requiring UL 1077 supplementary overcurrent protection.