SCHURTER 0034.4284 Board Mount Fuse — Equivalent & Substitute Parts

Part Overview

The SCHURTER 0034.4284 is a 2 A, 125 V AC/DC board mount fuse with fast blow response time, designed for through-hole radial mounting in radial can package configuration. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement continuity. Active alternatives from SCHURTER and Littelfuse manufacturers provide direct functional replacement with maintained electrical and mechanical compatibility.

Key Parameters

Parameter	Value
Current Rating	2 A
Voltage Rating (AC)	125 V
Voltage Rating (DC)	125 V
Response Time	Fast Blow
Mounting Type	Through Hole
Fuse Type	Board Mount (Cartridge Style Excluded)
Package / Case	Radial, Can
Size / Dimension	0.252" Dia x 0.346" H (6.40mm x 8.80mm)
RoHS Status	ROHS3 Compliant
Operating Temperature Range	-25°C ~ 85°C

Substitute Part Grouping Explanation

Substitute parts are grouped into two categories based on allowed electrical and mechanical parameters:

Parametric Equivalents (SCHURTER Series MSF 125): Parts 0034.4224 and 0034.4254 maintain identical electrical specifications (2 A, 125 V AC/DC, fast blow response) and mechanical dimensions (0.252" Dia x 0.346" H). These parts differ only in product status (active versus obsolete) and breaking capacity (100 A versus 300 A). Both are ROHS3 compliant and operate within the same temperature range (-25°C ~ 85°C). These represent direct parametric equivalents suitable for one-to-one replacement.

Similar Alternatives (Littelfuse MICRO™ 272, MICRO™ 273, and TR3® 303 Series): Parts 0272002.H, 0272002.V, 0273002.H, 0273002.V, and 30312000421 share identical current rating (2 A), AC voltage rating (125 V), response time (fast blow), mounting type (through hole), and fuse type (board mount). These alternatives maintain functional compatibility while introducing variations in breaking capacity, melting I²t, physical dimensions, and DC voltage rating (63 V for TR3® 303 series). Littelfuse alternatives provide enhanced thermal performance (-55°C ~ 125°C for MICRO™ series) and higher breaking capacity (10 kA for MICRO™ series).

Parameter Comparison

Part Number	Manufacturer	Series	Current (A)	Voltage AC (V)	Voltage DC (V)	Response Time	Breaking Capacity	Melting I²t	Size (mm)	Product Status	Approval Agency
0034.4284	SCHURTER	MSF 125	2	125	125	Fast Blow	300 A	0.43	6.40 x 8.80	Obsolete	cURus
0034.4224	SCHURTER	MSF 125	2	125	125	Fast Blow	100 A	0.43	6.40 x 8.80	Active	cURus
0034.4254	SCHURTER	MSF 125	2	125	125	Fast Blow	100 A	0.43	6.40 x 8.80	Active	cURus
0272002.H	Littelfuse	MICRO™ 272	2	125	125	Fast Blow	10 kA	0.3	5.97 x 7.30	Active	CSA, QPL, UL
0272002.V	Littelfuse	MICRO™ 272	2	125	125	Fast Blow	10 kA	0.3	5.97 x 7.30	Active	CSA, QPL, UL
0273002.H	Littelfuse	MICRO™ 273	2	125	125	Fast Blow	10 kA	0.3	6.35 x 8.89	Active	CSA, QPL, UL
0273002.V	Littelfuse	MICRO™ 273	2	125	125	Fast Blow	10 kA	0.3	6.35 x 8.89	Active	CSA, QPL, UL
30312000421	Littelfuse	TR3® 303	2	125	63	Fast Blow	50 A	0.17	6.00 x 8.00	Active	CSA, UL

Engineering Selection Recommendations

For Direct Replacement (Identical Electrical and Mechanical Specifications): Select SCHURTER 0034.4224 or 0034.4254 when PCB layout and mechanical constraints require exact dimensional match (0.252" Dia x 6.40mm x 8.80mm) and identical electrical performance. Both parts are active products with ROHS3 compliance and cURus certification. The reduced breaking capacity (100 A versus 300 A) is acceptable for applications where fault current does not exceed 100 A.

For Enhanced Performance and Thermal Range: Select Littelfuse MICRO™ 272 series (0272002.H or 0272002.V) when extended operating temperature range (-55°C ~ 125°C) and higher breaking capacity (10 kA) are required. These parts maintain identical current and voltage ratings with slightly reduced physical dimensions (5.97mm x 7.30mm). CSA, QPL, and UL certifications provide expanded regulatory acceptance.

For Dimensional Compatibility with Enhanced Specifications: Select Littelfuse MICRO™ 273 series (0273002.H or 0273002.V) when physical dimensions closely match the original part (6.35mm x 8.89mm versus 6.40mm x 8.80mm) while benefiting from 10 kA breaking capacity and extended thermal performance (-55°C ~ 85°C). UL and CSA certifications apply.

For DC Voltage-Limited Applications: Select Littelfuse TR3® 303 (30312000421) only when DC voltage requirement is 63 V or lower. This part introduces reduced breaking capacity (50 A) and lower melting I²t (0.17), making it unsuitable for applications requiring 125 V DC rating.

Frequently Asked Questions (FAQ)

Q: Can SCHURTER 0034.4224 or 0034.4254 be used as direct replacements for the obsolete 0034.4284?

A: Yes. Both parts maintain identical current rating (2 A), voltage ratings (125 V AC/DC), response time (fast blow), mounting type (through hole), and physical dimensions (6.40mm x 8.80mm). The reduced breaking capacity (100 A versus 300 A) is acceptable provided the application fault current does not exceed 100 A. Both are active products with ROHS3 compliance and cURus certification.

Q: What are the key differences between SCHURTER MSF 125 and Littelfuse MICRO™ 272 series?

A: Electrical specifications (2 A, 125 V AC/DC, fast blow) are identical. Littelfuse MICRO™ 272 offers higher breaking capacity (10 kA versus 100 A), extended operating temperature range (-55°C ~ 125°C versus -25°C ~ 85°C), and slightly smaller physical dimensions (5.97mm x 7.30mm versus 6.40mm x 8.80mm). Littelfuse parts carry CSA, QPL, and UL certifications versus cURus for SCHURTER.

Q: Can Littelfuse MICRO™ 273 series be used in place of MICRO™ 272?

A: Yes, for applications where physical dimensions permit. Both series maintain identical electrical specifications (2 A, 125 V AC/DC, fast blow, 10 kA breaking capacity). MICRO™ 273 dimensions (6.35mm x 8.89mm) are closer to the original SCHURTER part (6.40mm x 8.80mm) than MICRO™ 272 (5.97mm x 7.30mm). Operating temperature range for MICRO™ 273 is -55°C ~ 85°C.

Q: Is Littelfuse TR3® 303 (30312000421) suitable as a substitute?

A: TR3® 303 is suitable only for applications where DC voltage requirement is 63 V or lower. This part does not meet the 125 V DC requirement of the original specification. Additionally, breaking capacity (50 A) and melting I²t (0.17) are reduced compared to other alternatives.

Q: What certifications apply to each substitute part?

A: SCHURTER MSF 125 series (0034.4224, 0034.4254) carry cURus certification. Littelfuse MICRO™ 272 and MICRO™ 273 series carry CSA, QPL, and UL certifications. Littelfuse TR3® 303 carries CSA and UL certifications. All parts are ROHS3 compliant and REACH unaffected.

Q: Are there packaging differences between substitute parts?

A: SCHURTER 0034.4284 is packaged in bulk. All substitute parts (0034.4224, 0034.4254, Littelfuse series) are packaged in bulk. Moisture sensitivity level (MSL) is vendor undefined for the original part, not applicable for SCHURTER alternatives, and 1 (unlimited) for Littelfuse MICRO™ series.

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