Littelfuse 37421000430 Board Mount Fuse - Equivalent & Substitute Parts

Part Overview

The Littelfuse 37421000430 is a 10 A, 250 V AC/DC board mount fuse with slow blow response characteristics, designed for through-hole radial mounting in TR5® 374 series applications. This active product is widely used in power distribution and circuit protection applications requiring reliable overcurrent protection. Substitute parts become necessary when the primary part experiences supply constraints, when alternative certifications are required for specific markets, or when enhanced performance parameters are needed for upgraded designs.

Key Parameters

Parameter	Value
Current Rating	10 A
Voltage Rating (AC)	250 V
Response Time	Slow Blow
Mounting Type	Through Hole
Package / Case	Radial, Can, Vertical
Physical Dimensions	0.335" Dia x 0.315" H (8.50mm x 8.00mm)
Breaking Capacity @ Rated Voltage	50 A
Operating Temperature Range	-40°C ~ 85°C
RoHS Status	ROHS3 Compliant
Approval Agency	cULus

Substitute Part Grouping Explanation

Substitute parts for the 37421000430 are classified into two categories based on electrical and mechanical compatibility:

Direct Manufacturer Equivalents (Littelfuse TR5® 374 Series):

37421000410: Identical electrical specifications and physical dimensions. Differs only in packaging configuration (Bulk). Fully interchangeable for all applications.

Parametric Equivalents (Littelfuse TR5® 382 Series):

38221000410 and 38221000430: Match all critical electrical parameters (10 A, 250 V, Slow Blow, Through Hole Radial). Enhanced breaking capacity (100 A vs. 50 A) and higher melting I²t (365 vs. 280). Identical physical footprint. Extended certifications (cURus, PSE/JET). Suitable for applications requiring higher fault current ratings.

Cross-Manufacturer Equivalents (SCHURTER MSTU 250 Series):

0034.7125 and 0034.7325: Match core electrical specifications (10 A, 250 V, Slow Blow, Through Hole Radial). Identical breaking capacity (50 A). Slightly larger physical dimensions (0.335" Dia x 0.335" H vs. 0.335" Dia x 0.315" H). Higher melting I²t (564 vs. 280). Available in Bulk and Cut Tape packaging. cULus certification maintained.

Substitution is valid when all critical parameters align: current rating, voltage rating, response time, mounting type, package style, and physical dimensions within tolerance.

Parameter Comparison

Parameter	37421000430 (Main)	37421000410	38221000410	38221000430	0034.7125	0034.7325
Manufacturer	Littelfuse Inc.	Littelfuse Inc.	Littelfuse Inc.	Littelfuse Inc.	SCHURTER Inc.	SCHURTER Inc.
Series	TR5® 374	TR5® 374	TR5® 382	TR5® 382	MSTU 250	MSTU 250
Current Rating (A)	10	10	10	10	10	10
Voltage Rating - AC (V)	250	250	250	250	250	250
Response Time	Slow Blow	Slow Blow	Slow Blow	Slow Blow	Slow Blow	Slow Blow
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	Radial, Can, Vertical	Radial, Can, Vertical	Radial, Can, Vertical	Radial, Can, Vertical	Radial, Can, Vertical	Radial, Can, Vertical
Physical Dimensions	0.335" Dia x 0.315" H (8.50mm x 8.00mm)	0.335" Dia x 0.315" H (8.50mm x 8.00mm)	0.335" Dia x 0.315" H (8.50mm x 8.00mm)	0.335" Dia x 0.315" H (8.50mm x 8.00mm)	0.335" Dia x 0.335" H (8.50mm x 8.50mm)	0.335" Dia x 0.335" H (8.50mm x 8.50mm)
Breaking Capacity @ Rated Voltage (A)	50	50	100	100	50	50
Melting I²t	280	280	365	365	564	564
DC Cold Resistance (Ohms)	0.005	0.005	0.0042	0.0042	—	—
Approval Agency	cULus	cULus	cURus, PSE/JET	cURus, PSE/JET	cULus	cULus
Operating Temperature Range	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Product Status	Active	Active	Active	Active	Active	Active

Engineering Selection Recommendations

For Direct Replacement (No Design Changes Required): Select 37421000410 when the primary part 37421000430 is unavailable. Both parts are Littelfuse TR5® 374 series with identical electrical and mechanical specifications. Packaging differs (Bulk vs. Cut Tape), but functional performance is equivalent. cULus certification is maintained.

For Enhanced Fault Current Protection: Select 38221000410 or 38221000430 (Littelfuse TR5® 382 series) when applications require higher breaking capacity (100 A vs. 50 A) or when PSE/JET certifications are mandated for specific markets. These parts maintain identical current, voltage, and response characteristics while providing superior fault current handling. Physical footprint remains unchanged. Higher melting I²t (365 vs. 280) indicates improved thermal performance.

For Cross-Manufacturer Sourcing: Select 0034.7125 or 0034.7325 (SCHURTER MSTU 250 series) when Littelfuse parts are unavailable and alternative suppliers are required. These parts match all critical electrical parameters and maintain cULus certification. Physical height is slightly increased (0.335" vs. 0.315"), which must be verified against PCB layout constraints. Higher melting I²t (564 vs. 280) provides enhanced thermal margin. Packaging options include Bulk (0034.7125) and Cut Tape (0034.7325).

All substitute parts maintain ROHS3 compliance, REACH unaffected status, and operating temperature range (-40°C ~ 85°C) consistent with the main part.

Frequently Asked Questions (FAQ)

Q: Can 37421000410 be used as a direct replacement for 37421000430? A: Yes. Both parts are Littelfuse TR5® 374 series with identical electrical specifications (10 A, 250 V, Slow Blow), physical dimensions (0.335" Dia x 0.315" H), and certifications (cULus). The only difference is packaging configuration. Functional performance is equivalent.

Q: What is the advantage of using 38221000410 or 38221000430 over the main part? A: The TR5® 382 series offers higher breaking capacity (100 A vs. 50 A) and higher melting I²t (365 vs. 280), providing enhanced protection in applications with higher fault currents. These parts also include PSE/JET certifications in addition to cULus, making them suitable for broader market requirements. Physical footprint and electrical ratings remain identical.

Q: Are SCHURTER 0034.7125 and 0034.7325 physically compatible with the Littelfuse parts? A: Both parts share the same radial, can, vertical package style and identical diameter (0.335"). However, height differs slightly: SCHURTER parts are 0.335" H compared to Littelfuse parts at 0.315" H. This 0.020" (0.50mm) difference must be verified against PCB layout and clearance requirements before substitution.

Q: What is the difference between 0034.7125 and 0034.7325? A: Both are SCHURTER MSTU 250 series with identical electrical and physical specifications. The difference is packaging: 0034.7125 is supplied in Bulk, while 0034.7325 is supplied in Cut Tape (CT). Electrical performance and physical dimensions are identical.

Q: Can I substitute a SCHURTER part for a Littelfuse part in an existing design? A: Substitution is valid if PCB layout accommodates the slightly larger height (0.335" vs. 0.315"). All electrical parameters, certifications (cULus), and operating temperature ranges are compatible. Verify clearance above the fuse location before implementation.

Q: Are all substitute parts ROHS3 compliant? A: Yes. All parts listed—37421000410, 38221000410, 38221000430, 0034.7125, and 0034.7325—are ROHS3 compliant and REACH unaffected, matching the compliance status of the main part 37421000430.

Q: Which substitute part should I select for maximum thermal margin? A: SCHURTER 0034.7125 or 0034.7325 provide the highest melting I²t (564), compared to Littelfuse TR5® 374 (280) and TR5® 382 (365). This indicates superior thermal performance and slower response to transient overcurrents. Selection depends on application requirements and physical space constraints.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message