Littelfuse 38214000000 Board Mount Fuse - Equivalent & Substitute Parts

Part Overview

The Littelfuse 38214000000 is a 4 A, 250 V AC/DC board mount fuse with slow blow response characteristics, designed for through-hole radial mounting in vertical orientation. This TR5® 382 series fuse is actively produced and widely stocked (15,542 pcs available). Alternative equivalent parts may be required due to supply constraints, design revisions, or regional availability considerations.

Key Parameters

Parameter	Value
Current Rating	4 A
Voltage Rating (AC)	250 V
Response Time	Slow Blow
Mounting Type	Through Hole
Package / Case	Radial, Can, Vertical
Size / Dimension	0.335" Dia x 0.315" H (8.50mm x 8.00mm)
Operating Temperature Range	-40°C ~ 85°C
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility for the 38214000000 is determined by the following critical parameters:

Primary Matching Criteria (Mandatory):

Current Rating: 4 A
Voltage Rating (AC): 250 V
Response Time: Slow Blow
Mounting Type: Through Hole
Package / Case: Radial, Can, Vertical
Operating Temperature Range: -40°C ~ 85°C minimum
RoHS Compliance: ROHS3 Compliant

Secondary Considerations (Application-Dependent):

Breaking Capacity @ Rated Voltage
Melting I²t characteristics
DC Cold Resistance
Approval Agency certifications
Physical dimensions (tolerance for board layout)

Parts meeting all primary criteria are classified as parametric equivalents. Parts with variations in secondary parameters require application-level verification for specific circuit protection requirements.

Parameter Comparison

Parameter	38214000000 (Main)	37214000001	37414000000	0034.6981	RST 3.15-AMMO
Manufacturer	Littelfuse Inc.	Littelfuse Inc.	Littelfuse Inc.	SCHURTER Inc.	Bel Fuse Inc.
Current Rating (Amps)	4 A	4 A	4 A	4 A	3.15 A
Voltage Rating - AC	250 V	250 V	250 V	250 V	250 V
Response Time	Slow Blow	Slow Blow	Slow Blow	Slow Blow	Slow Blow
Mounting Type	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, Box
Size / Dimension	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)	0.329" L x 0.157" W x 0.303" H (8.35mm x 4.00mm x 7.70mm)
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-55°C ~ 125°C
Breaking Capacity @ Rated Voltage	100 A	40 A	50 A	100 A	100 A
Melting I²t	72	126.4	36	77	69
DC Cold Resistance (Ohms)	0.0138	0.0129	0.017	Not Specified	0.017
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Product Status	Active	Active	Active	Active	Active

Engineering Selection Recommendations

Littelfuse 37214000001 (TR5® 372 Series) Parametric equivalent with identical electrical ratings and physical dimensions. Breaking capacity reduced to 40 A and melting I²t increased to 126.4 compared to the main part. Active product status with 5,382 pcs in stock. Suitable for applications where lower breaking capacity is acceptable.

Littelfuse 37414000000 (TR5® 374 Series) Parametric equivalent with identical electrical ratings and physical dimensions. Breaking capacity of 50 A and melting I²t of 36 provide different thermal characteristics. CSA and cULus certifications (subset of main part approvals). Active product status with 5,100 pcs in stock.

SCHURTER 0034.6981 (MXT 250 Series) Direct manufacturer equivalent with matching electrical ratings and breaking capacity of 100 A. Physical dimension height increased to 0.335" (8.50mm) versus 0.315" (8.00mm) on main part. Melting I²t of 77 closely matches main part. Active product status with 7,694 pcs in stock. Board layout verification required due to height variation.

Bel Fuse RST 3.15-AMMO (RST Series) Current rating of 3.15 A represents a 21% reduction from the 4 A main part specification. Package case differs (Radial, Box versus Radial, Can, Vertical). Operating temperature range extended to -55°C ~ 125°C. Physical dimensions significantly different. Not a direct parametric equivalent; application-specific evaluation required.

Frequently Asked Questions (FAQ)

Q: Can I use part 37214000001 as a direct replacement for 38214000000? A: Yes, for applications where the reduced breaking capacity of 40 A is acceptable. Both parts share identical current rating (4 A), voltage rating (250 V), response time (Slow Blow), mounting type (Through Hole), package case (Radial, Can, Vertical), and physical dimensions (0.335" Dia x 0.315" H). The primary difference is breaking capacity and melting I²t characteristics.

Q: What is the impact of the height difference in the SCHURTER 0034.6981? A: The SCHURTER part is 0.020" (0.50mm) taller than the main part (0.335" H versus 0.315" H). This dimension variation requires verification against board layout constraints, component spacing, and enclosure clearances before implementation.

Q: Why is the Bel Fuse RST 3.15-AMMO listed as a substitute if the current rating is different? A: The RST 3.15-AMMO is listed in the original substitute data but does not meet the primary matching criterion of 4 A current rating. This part is a lower-rated alternative suitable only for applications where 3.15 A protection is acceptable. Physical package differences (Radial, Box versus Radial, Can, Vertical) also require board design verification.

Q: Are all substitute parts ROHS3 compliant? A: Yes. All listed parts, including the main part 38214000000 and all substitutes, are ROHS3 compliant.

Q: Which substitute has the closest thermal characteristics to the main part? A: The SCHURTER 0034.6981 has a melting I²t of 77, which is closest to the main part's 72. The Bel Fuse RST 3.15-AMMO has a melting I²t of 69, also closely aligned, but the current rating difference limits its applicability.

Q: What certifications should I verify for my specific application? A: The main part 38214000000 carries CCC, cURus, KC, PSE/JET, SEMKO, and VDE approvals. Substitute parts carry different certification subsets. Verify that the selected substitute meets the regulatory requirements for your target market and application.

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