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Siemens 5SX21D4 1-Pole Miniature Circuit Breaker — 4A

Siemens 5SX21D4 1-Pole Miniature Circuit Breaker

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ManufacturerSiemens

Part number5SX21D4

Poles 1

Rated Current 4A

Breaking Capacity 6kA

Voltage Rating 400V AC

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Veteran-owned

CAGE: 9NK75

1-Pole configuration C-curve tripping 6kA interrupting rating 400V AC operational voltage Compact design DIN rail compatible

Product description

The Siemens 5SX21D4 is a 1-pole miniature circuit breaker (MCB) from the 5SX series, providing essential overcurrent protection for electrical circuits. It is characterized by its C-curve tripping, a rated current of 4A, a breaking capacity of 6kA, and an operating voltage of 400V AC. This device is crucial for preventing damage from short circuits and overloads.

This MCB is ideal for use in applications requiring precise protection for lower current loads, such as lighting circuits in residential or commercial buildings, and control circuits in industrial automation. Its compact size and reliable performance make it a staple in electrical distribution systems.

Stanlo Automation, a veteran-owned surplus parts distributor, is your reliable source for industrial automation components, including the Siemens 5SX21D4. We ensure product availability and prompt delivery to minimize downtime for your critical systems.

Technical specifications

Poles	1
Rated Current	4A
Breaking Capacity	6kA
Voltage Rating	400V AC
Tripping Curve	C
Series	5SX

Common applications

Lighting circuits

Control circuits

Residential electrical panels

Commercial distribution

Miniature circuit protection

Low current load protection

Compatible systems

Standard DIN rail mounting Electrical distribution systems

Also known as

Siemens 5SX21D4 MCB 4A Siemens circuit breaker 5SX21D4 breaker

Replaces / compatible with

This circuit breaker is suitable for replacing older Siemens 1-pole MCBs with similar specifications in the 5SX series or compatible product lines.

Technical note

Expert tip

Verify that the circuit's expected inrush current does not exceed the 5-10x rated current trip threshold of the C-curve characteristic.

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Frequently asked questions

What are the typical applications for the Siemens 5SX21D4 circuit breaker?

The Siemens 5SX21D4 is commonly used for protecting lighting circuits and control circuits where lower current ratings are required. Its C-curve characteristic is suitable for loads that might experience moderate inrush currents, such as fluorescent lighting or small motor controls.