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Siemens Miniature Circuit Breaker 5SX21-B20, 20A, Type B

Siemens Miniature Circuit Breaker, 20A, Type B, 1-pole.

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ManufacturerSiemens

Part number5SX21-B20

Poles 1

Rated Current 20 A

Trip Curve Type B

Breaking Capacity 6 kA

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1-Pole Design 20A Current Rating Type B Trip Curve 6 kA Breaking Capacity Overload & Short Circuit Protection DIN Rail Mountable

Product description

The Siemens Miniature Circuit Breaker (MCB) 5SX21-B20 is a single-pole circuit breaker with a rated current of 20A. It features a Type B tripping characteristic, which is designed for the protection of circuits against overloads and short circuits, typically used for resistive or inductive loads where low inrush currents are expected.

This MCB is suitable for various applications in industrial and residential electrical installations, providing essential overcurrent protection for circuits in control panels, distribution boards, and machinery.

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Technical specifications

Poles	1
Rated Current	20 A
Trip Curve	Type B
Breaking Capacity	6 kA
Voltage	230/400 V AC
Series	5SX2

Common applications

Electrical Distribution

Control Panels

Machinery Protection

Residential Wiring

Industrial Installations

Overcurrent Protection

Compatible systems

Standard DIN Rail Mounting Systems Electrical Distribution Boards Control Cabinets

Also known as

Siemens 5SX2 20A B-Curve 1-Pole Circuit Breaker 5SX21-B20 Siemens MCB B20

Replaces / compatible with

Standard replacement for Siemens 5SX2 series Type B miniature circuit breakers with similar specifications.

Technical note

Expert tip

The Type B tripping characteristic means the breaker trips between 3 and 5 times the rated current, making it suitable for circuits where excessive inrush current is not expected.

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Frequently asked questions

What type of loads is the Siemens 5SX21-B20 Type B circuit breaker best suited for?

The Siemens 5SX21-B20, with its Type B tripping curve, is designed for circuits with low inrush currents. It is typically used for protecting purely resistive loads or inductive loads with very low starting currents, such as lighting circuits and some small motor applications.