Bel Fuse Inc. 3JS 4.6-R Glass Cartridge Fuse Equivalent & Substitute Parts

Part Overview

The Bel Fuse Inc. 3JS 4.6-R is a 4.6 A slow-blow glass cartridge fuse rated for 350 V AC and 140 V DC operation. This through-hole mounted component uses the standard 2AG form factor (5mm x 15mm axial) and is designed for circuit protection in industrial and commercial applications. The part maintains active product status with full compliance to CE, CSA, cURus, and PSE approval standards. Equivalent and substitute parts are identified when electrical ratings, mechanical form factors, and safety certifications align with application requirements.

Substiute Parts

3JS 3.5-R

Bel Fuse Inc.In Stock: 21453JS 3.5-R Datasheet

Current PartRFQ

020903.5MXEP

Littelfuse Inc.In Stock: 2835020903.5MXEP Datasheet

SimilarRFQ

023003.5MXP

Littelfuse Inc.In Stock: 4722023003.5MXP Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 3JS 4.6-R is determined by the following critical parameters:

• Current Rating: Must be 4.6 A
• Response Time: Must be Slow Blow
• Fuse Type: Must be Cartridge, Glass
• Mounting Type: Must be Through Hole
• Voltage Rating - AC: Must be ≥ 350 V
• Voltage Rating - DC: Must be ≥ 140 V (where applicable)
• Operating Temperature Range: Must support -55°C ~ 125°C
• RoHS Compliance: Must maintain ROHS3 status

Two substitute parts meet these criteria with allowable variations in physical dimensions and melting I²t characteristics, provided the electrical performance envelope is maintained or exceeded.

Parameter Comparison

Engineering Selection Recommendations

Littelfuse 020904.6MXEP is the primary substitute for the 3JS 4.6-R. This part maintains identical current rating, AC voltage rating, response time, and standard 2AG form factor. The operating temperature range and RoHS compliance are equivalent. Physical dimensions are within acceptable tolerance for through-hole mounting applications. DC voltage rating is not specified for this part; applications requiring explicit DC voltage confirmation should reference manufacturer documentation. Approval certifications include CE, cULus, and PSE.

Littelfuse 023004.6MXP is a secondary substitute with the same current rating and response time. However, the AC voltage rating is reduced to 250 V, and the package case is classified as non-standard rather than standard 2AG. This part is suitable only for applications where the circuit operates at 250 V AC or lower. The DC voltage rating of 125 V is lower than the original specification. This part carries broader approval certifications including UL and CSA. Physical dimensions differ slightly from the original part.

Selection between these substitutes depends on circuit voltage requirements and form factor constraints. The 020904.6MXEP maintains closer electrical equivalence to the original part. The 023004.6MXP requires voltage derating and is suitable only for lower-voltage applications.

Frequently Asked Questions (FAQ)

Q: Can the Littelfuse 020904.6MXEP be used as a direct replacement for the Bel Fuse 3JS 4.6-R?

A: Yes, for applications operating at 350 V AC or lower. Both parts share identical current rating (4.6 A), response time (slow blow), form factor (2AG, 5mm x 15mm), and operating temperature range (-55°C ~ 125°C). Physical dimensions are within acceptable tolerance for standard through-hole fuse holders. The DC voltage rating for the 020904.6MXEP is not specified; verify with the manufacturer if DC operation at 140 V is required.

Q: What are the voltage limitations of the Littelfuse 023004.6MXP?

A: The 023004.6MXP is rated for 250 V AC and 125 V DC, both lower than the original 3JS 4.6-R specifications (350 V AC, 140 V DC). This part is suitable only for circuits designed to operate within these reduced voltage limits. Do not use this part in applications requiring the full 350 V AC or 140 V DC rating.

Q: Are there physical form factor differences between these substitutes?

A: The 020904.6MXEP maintains the standard 2AG form factor (5mm x 15mm) identical to the original part. The 023004.6MXP uses a non-standard cartridge form factor with slightly different dimensions (4.50mm x 14.50mm). Verify that your fuse holder accommodates the non-standard form factor before selecting the 023004.6MXP.

Q: Do all three parts meet the same safety certifications?

A: No. The original 3JS 4.6-R carries CE, CSA, cURus, and PSE certifications. The 020904.6MXEP carries CE, cULus, and PSE. The 023004.6MXP carries CE, CSA, PSE, and UL. Applications requiring specific certification compliance should verify that the selected substitute meets all required approval standards.

Q: What is the significance of the melting I²t difference?

A: The original part has a melting I²t of 69, while both Littelfuse substitutes have a melting I²t of 110. This indicates the substitutes require slightly more thermal energy to melt. For applications with precise thermal protection requirements, this difference may be significant. Consult application-specific thermal analysis to determine acceptability.

Q: Can these parts be used interchangeably in the same circuit board?

A: The 020904.6MXEP can be used interchangeably with the original part in standard through-hole fuse holders designed for 2AG form factors. The 023004.6MXP requires a fuse holder compatible with its non-standard cartridge form factor and cannot be used in standard 2AG holders. Verify mechanical compatibility before installation.