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Siemens 5SJ4120-8HG40 1-Pole D-Curve Circuit Breaker - 20A

Siemens 5SJ4120-8HG40 1-pole, D-curve, 20A miniature circuit breaker.

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ManufacturerSiemens

Part number5SJ4120-8HG40

Type Miniature Circuit Breaker

Poles 1

Current Rating 20 A

Tripping Characteristic D

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1-pole design D-curve tripping 14kA interrupting capacity UL 489 listed 20A rating 70mm width Equal polarity

Product description

The Siemens 5SJ4120-8HG40 is a single-pole miniature circuit breaker featuring a D-curve tripping characteristic, rated for 20A. It offers a high short-circuit breaking capacity of 14kA and is designed for 240V systems. The breaker has a width of 70mm and complies with UL 489 standards, including equal polarity.

This circuit breaker is ideal for protecting circuits with high inrush currents, such as those powering motors, transformers, and other inductive loads. The D-curve provides a time delay before tripping, preventing nuisance tripping during these temporary current surges.

Stanlo Automation, a trusted veteran-owned distributor of surplus industrial automation parts, offers the Siemens 5SJ4120-8HG40. Source this reliable circuit breaker from us to ensure your machinery and systems are protected while optimizing your procurement costs.

Technical specifications

Type	Miniature Circuit Breaker
Poles	1
Current Rating	20 A
Tripping Characteristic	D
Breaking Capacity	14 kA
Voltage Rating	240V AC
Depth	70 mm
Standard	UL 489
Polarity	Equal

Common applications

Motor control circuits

Transformer protection

Industrial machinery

Power distribution

Automation systems

Compatible systems

Motor starters Control transformers Industrial automation equipment Power distribution panels

Also known as

Siemens 5SJ4120-8HG40 5SJ4 Series breaker Siemens 20A D-curve MCB

Replaces / compatible with

This part replaces older Siemens miniature circuit breakers with equivalent specifications and equal polarity. Check the Siemens 5SJ4 series documentation for direct compatibility.

Technical note

Expert tip

The 70mm depth and equal polarity features are important considerations for panel design and installation efficiency, ensuring proper fit and flexible wiring options.

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Frequently asked questions

What applications are best suited for the Siemens 5SJ4120-8HG40 with its D-curve and equal polarity?

The D-curve characteristic of the Siemens 5SJ4120-8HG40 makes it ideal for circuits with high inrush currents, such as those powering motors or transformers. The equal polarity simplifies installation by allowing interchangeable line and load connections.