Equivalent & Substitute Parts for 3SB 3 Glass Cartridge Fuse

Part Overview

The 3SB 3 is a 3 A, 250 V AC/DC glass cartridge fuse manufactured by Bel Fuse Inc. with slow-blow response characteristics. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing system maintenance and new designs. The fuse requires a 3AB or 3AG holder and is designed for applications requiring 1/4" x 1-1/4" form factor protection.

Substiute Parts

3SB 3

Bel Fuse Inc.In Stock: 11233SB 3 Datasheet

Current PartRFQ

3SB 3-R

Bel Fuse Inc.In Stock: 64003SB 3-R Datasheet

DirectRFQ

0313003.MXP

Littelfuse Inc.In Stock: 24850313003.MXP Datasheet

DirectRFQ

0313003.VXP

LittelfuseIn Stock: 8590313003.VXP Datasheet

DirectRFQ

0313003.HXIDP

Littelfuse Inc.In Stock: 11360313003.HXIDP Datasheet

SimilarRFQ

0313003.HXP

LittelfuseIn Stock: 35270313003.HXP Datasheet

SimilarRFQ

0313003.VXIDP

Littelfuse Inc.In Stock: 8010313003.VXIDP Datasheet

SimilarRFQ

TSA-3A

OptiFuseIn Stock: 4347TSA-3A Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the 3SB 3 is determined by strict equivalence across the following parameters:

• Current Rating: 3 A (exact match required)
• Voltage Rating: 250 V AC (exact match required)
• Fuse Type: Cartridge, Glass (exact match required)
• Response Time: Slow Blow (exact match required)
• Package / Case: 3AB, 3AG, 1/4" x 1-1/4" (exact match required)
• Mounting Type: Requires Holder (exact match required)
• Operating Temperature Range: -55°C ~ 125°C (exact match required)

All substitute parts listed below meet these core electrical and mechanical parameters. Variations in breaking capacity, melting I²t, DC cold resistance, and approval agencies do not disqualify substitution when the primary parameters align.

Parameter Comparison

Engineering Selection Recommendations

All listed substitute parts maintain electrical and mechanical compatibility with the 3SB 3. Selection should prioritize active product status and compliance requirements:

Primary Recommendation: 3SB 3-R (Bel Fuse Inc.) provides direct manufacturer continuity from the obsolete 3SB 3, maintains identical electrical characteristics, and achieves ROHS3 compliance with higher breaking capacity (200A vs. 100A).

Alternative Selections: Littelfuse 0313003 series parts (MXP, VXP, HXIDP, HXP, VXIDP) are active products with ROHS3 compliance. These parts exhibit slightly different dimensional tolerances (1.250" vs. 1.252" length) and higher melting I²t values (200 vs. 146), but remain mechanically compatible with 3AB and 3AG holders.

Secondary Option: TSA-3A (OptiFuse) meets all core electrical and mechanical parameters with ROHS3 compliance and active product status. This part exhibits significantly lower melting I²t (18.71), which may affect thermal response characteristics in specific circuit applications.

Frequently Asked Questions (FAQ)

Q: Can I use 3SB 3-R as a direct replacement for the obsolete 3SB 3?

A: Yes. The 3SB 3-R maintains identical current rating (3 A), voltage rating (250 V AC), response time (slow blow), package designation (3AB, 3AG), and operating temperature range (-55°C ~ 125°C). The higher breaking capacity (200A vs. 100A) and ROHS3 compliance represent improvements over the original part.

Q: What is the difference between Littelfuse 0313003.MXP and 0313003.VXP?

A: Both parts are electrically and mechanically equivalent. They share identical current rating, voltage rating, response time, package designation, and operating temperature range. Differences in approval agencies (0313003.MXP includes K-MARK; 0313003.VXP includes KC) reflect regional certification variations and do not affect substitution compatibility.

Q: Are there dimensional differences between substitute parts?

A: Yes. The original 3SB 3 and 3SB 3-R measure 0.250" Dia x 1.252" L. Littelfuse 0313003 series parts measure 0.250" Dia x 1.250" L (0.002" shorter). TSA-3A matches the original at 0.250" Dia x 1.252" L. All dimensions remain compatible with standard 3AB and 3AG holders.

Q: Does melting I²t variation affect substitution suitability?

A: Melting I²t values differ across substitutes (146 to 200 for Littelfuse parts; 18.71 for TSA-3A). This parameter influences thermal response time but does not disqualify substitution when current rating, voltage rating, and response time classification (slow blow) remain constant. Circuit-specific thermal requirements should be evaluated during design review.

Q: Which substitute parts are RoHS compliant?

A: All active substitute parts listed (3SB 3-R, 0313003.MXP, 0313003.VXP, 0313003.HXIDP, 0313003.HXP, 0313003.VXIDP, TSA-3A) achieve ROHS3 compliance. The original 3SB 3 is RoHS non-compliant.

Q: Can I mix different substitute part manufacturers in the same circuit?

A: Yes, provided all parts meet the required electrical and mechanical parameters. However, maintaining consistency within a single design is recommended for supply chain stability and performance predictability.