SCHURTER 0034.7121 Board Mount Fuse - Equivalent & Substitute Parts

Part Overview

The SCHURTER 0034.7121 is a 4 A, 250 V AC/DC board mount fuse with radial, can, vertical package configuration. This component is designed for through-hole mounting applications requiring slow-blow fuse protection in industrial and commercial electronics. The part is currently active in production with 900 pieces available in inventory. Substitute parts are identified to provide alternative sourcing options when the primary part number is unavailable or when design flexibility permits component interchange.

Key Parameters

Parameter	Value
Manufacturer Part Number	0034.7121
Manufacturer	SCHURTER Inc.
Current Rating	4 A
Voltage Rating (AC)	250 V
Fuse Type	Board Mount (Cartridge Style Excluded)
Response Time	Slow Blow
Mounting Type	Through Hole
Package / Case	Radial, Can, Vertical
Size / Dimension	0.335" Dia x 0.335" H (8.50mm x 8.50mm)
Operating Temperature Range	-40°C ~ 85°C
Product Status	Active

Substitute Part Grouping Explanation

Substitute parts for the SCHURTER 0034.7121 are qualified based on the following critical parameters that must remain constant for direct interchange:

Current Rating: 4 A (exact match required)
Voltage Rating (AC): 250 V (exact match required)
Response Time: Slow Blow (exact match required)
Mounting Type: Through Hole (exact match required)
Package / Case: Radial, Can, Vertical (exact match required)
Size / Dimension: 0.335" Dia x 0.335" H (8.50mm x 8.50mm) (exact match required)
Operating Temperature Range: -40°C ~ 85°C (exact match required)

Two substitute parts meet these criteria: SCHURTER 0034.6921 and SCHURTER 0034.7221. Both maintain identical electrical and mechanical specifications to the primary part number, ensuring functional compatibility in board mount fuse applications.

Parameter Comparison

Parameter	0034.7121 (Main)	0034.6921 (Substitute)	0034.7221 (Substitute)
Manufacturer	SCHURTER Inc.	SCHURTER Inc.	SCHURTER Inc.
Current Rating (Amps)	4 A	4 A	4 A
Voltage Rating - AC	250 V	250 V	250 V
Response Time	Slow Blow	Slow Blow	Slow Blow
Mounting Type	Through Hole	Through Hole	Through Hole
Fuse Type	Board Mount (Cartridge Style Excluded)	Board Mount (Cartridge Style Excluded)	Board Mount (Cartridge Style Excluded)
Package / Case	Radial, Can, Vertical	Radial, Can, Vertical	Radial, Can, Vertical
Size / Dimension	0.335" Dia x 0.335" H (8.50mm x 8.50mm)	0.335" Dia x 0.335" H (8.50mm x 8.50mm)	0.335" Dia x 0.335" H (8.50mm x 8.50mm)
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Product Status	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected
Series	MSTU 250	MXT 250	MSTU 250
Breaking Capacity @ Rated Voltage	50A	100A	50A
Melting I²t	67.2	77	67.2
Approval Agency	cULus	CCC, cURus, KC, PSE/JET, VDE	cULus
Inventory	900 Pcs	4874 Pcs	938 Pcs

Engineering Selection Recommendations

All three part numbers—0034.7121, 0034.6921, and 0034.7221—are active products manufactured by SCHURTER Inc. and maintain identical core electrical and mechanical specifications required for board mount fuse applications.

The 0034.6921 substitute offers higher breaking capacity (100A versus 50A) and broader regulatory approvals (CCC, cURus, KC, PSE/JET, VDE versus cULus). This part is suitable for applications requiring enhanced fault protection margins or compliance with additional international standards.

The 0034.7221 substitute maintains identical breaking capacity and approval agency specifications to the primary part number 0034.7121, providing direct functional equivalence with no performance trade-offs.

All parts are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements for electronic component manufacturing and distribution.

Frequently Asked Questions (FAQ)

Q: Can 0034.6921 be used as a direct replacement for 0034.7121?

A: Yes. Both parts share identical current rating (4 A), voltage rating (250 V AC), response time (Slow Blow), mounting type (Through Hole), package configuration (Radial, Can, Vertical), physical dimensions (0.335" Dia x 0.335" H), and operating temperature range (-40°C ~ 85°C). The 0034.6921 provides higher breaking capacity (100A) and additional regulatory certifications, making it functionally compatible for direct board-level substitution.

Q: What is the difference between 0034.7121 and 0034.7221?

A: Both parts are functionally identical across all critical electrical and mechanical parameters. The primary difference is series designation: 0034.7121 belongs to the MSTU 250 series, while 0034.7221 also belongs to the MSTU 250 series. Both maintain identical breaking capacity (50A) and approval agency certifications (cULus). These parts are interchangeable for through-hole board mount fuse applications.

Q: Are all three parts suitable for the same PCB footprint?

A: Yes. All three parts share identical physical dimensions (0.335" Dia x 0.335" H / 8.50mm x 8.50mm) and radial, can, vertical package configuration. They are designed for the same through-hole mounting pattern and require no PCB layout modifications for interchange.

Q: What regulatory certifications apply to these fuse parts?

A: The 0034.7121 and 0034.7221 carry cULus approval. The 0034.6921 carries broader certifications: CCC, cURus, KC, PSE/JET, and VDE. All three parts are ROHS3 compliant and REACH unaffected, meeting current environmental standards for electronic components.

Q: Can these fuses be used in both AC and DC applications?

A: Yes. All three parts are rated for 4 A at 250 V AC/DC, indicating suitability for both alternating and direct current circuit protection applications within the specified voltage and current parameters.

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