ABB FS401, S400, SmiSSline S400M Miniature Circuit Breaker, 1-Pole, 4 A, Type C, Type D, Type K, Type B, 400 V AC, 250 V

RS Stock No.:: 177-838
Mfr. Part No.:: 2CCS571001R0045 S401M-B4
Brand:: ABB

ABB FS401, S400, SmiSSline S400M Miniature Circuit Breaker, 1-Pole, 4 A, Type C, Type D, Type K, Type B, 400 V AC, 250 V

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Subtotal (1 unit)*

£30.41

(exc. VAT)

£36.49

(inc. VAT)

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In Stock

Plus 9 unit(s) shipping from 09 February 2026

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Units	Per unit
1 +	£30.41

*price indicative

RS Stock No.:: 177-838
Mfr. Part No.:: 2CCS571001R0045 S401M-B4
Brand:: ABB

Specifications

Technical Reference

Legislation and Compliance

Product Details

Find similar products by selecting one or more attributes.

Select all	Attribute	Value
	Brand	ABB
	Number of Poles	1
	Product Type	Miniature Circuit Breaker
	Current Rating	4 A
	Tripping Characteristics	Type C, Type D, Type K, Type B
	Rated AC Voltage	400 V
	Rated DC Voltage	250 V
	Breaking Capacity	10kA
	Mount Type	DIN Rail
	Range	FS401, S400, SmiSSline
	Series	S400M
	Width	18 mm
	Depth	97mm
	Standards/Approvals	EN 60898-1, IEC/EN 60947-2

	Select all
	Brand ABB
	Number of Poles 1
	Product Type Miniature Circuit Breaker
	Current Rating 4 A
	Tripping Characteristics Type C, Type D, Type K, Type B
	Rated AC Voltage 400 V
	Rated DC Voltage 250 V
	Breaking Capacity 10kA
	Mount Type DIN Rail
	Range FS401, S400, SmiSSline
	Series S400M
	Width 18 mm
	Depth 97mm
	Standards/Approvals EN 60898-1, IEC/EN 60947-2

COO (Country of Origin):: CH

ABB MCB, 10kA Short-Circuit Capacity, IP20 Rating - S400M Series - S401M-B4

Use this MCB from ABB to protect people and equipment in your workspace from the harmful effects of overvoltage. As a type B breaking component, it trips quickly to break the circuit and stop electrical energy whenever it's supplied with between 3 and 5 times the 4A rated load. This makes it a practical choice in lower-powered residential settings as its quick tripping action helps to ensure effective protection when even slight overcurrent faults occur. As part of ABB's innovative SMISSLINE TP plug-in distribution system, it's specifically designed for easy mounting and quick dismounting with the assurance of touch protection.

Features & Benefits

• Withstands inrush voltage rating of 4kV, so prevents large surges causing equipment failure

• Inspection window displays pole conductor contacting for easy status checks

• Comes with integrated input wiring, so is ready to install

• IP20 rating means it's finger-safe and protected against objects larger than 12mm

Applications

• Welding equipment

• Industrial lighting

• Factory automation

How do I mount this MCB?

You can easily mount this MCB directly onto a standard 35mm DIN rail without needing to use any tools.