Equivalent & Substitute Parts for 3SB 125-R Glass Cartridge Fuse

Part Overview

The 3SB 125-R is a 125 mA, 250 V AC/DC glass cartridge fuse manufactured by Bel Fuse Inc. This component is classified as obsolete, making substitute parts necessary for ongoing system maintenance and new designs. The fuse is designed for use with 3AB and 3AG holders and provides slow-blow response characteristics suitable for circuits requiring transient current tolerance.

Substiute Parts

3SB 125-R

Bel Fuse Inc.In Stock: 9393SB 125-R Datasheet

Current PartRFQ

0313.125HXP

Littelfuse Inc.In Stock: 11080313.125HXP Datasheet

DirectRFQ

0313.125MXP

Littelfuse Inc.In Stock: 18240313.125MXP Datasheet

DirectRFQ

0313.125VXP

Littelfuse Inc.In Stock: 7920313.125VXP Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the 3SB 125-R is based on electrical and mechanical parameter alignment. The following criteria determine compatibility:

• Current Rating: 125 mA (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)
• Operating Temperature Range: -55°C ~ 125°C (exact match required)
• RoHS Compliance: ROHS3 Compliant (required for regulatory alignment)

All substitute parts listed below meet these criteria and are manufactured by Littelfuse Inc., an active supplier with current product status.

Parameter Comparison

Engineering Selection Recommendations

All three Littelfuse substitute parts (0313.125HXP, 0313.125MXP, 0313.125VXP) meet the electrical and mechanical requirements for direct substitution of the obsolete 3SB 125-R. These parts are manufactured by an active supplier with current product status, ensuring long-term availability and supply chain continuity.

The substitute parts carry CE, CSA, and UL certifications, providing regulatory compliance for applications requiring these standards. All parts maintain ROHS3 compliance and operate within the same temperature range as the original component.

Selection among the three substitute options may be based on packaging availability and inventory levels, as all three parts are electrically and mechanically equivalent.

Frequently Asked Questions (FAQ)

Q: Can 0313.125HXP, 0313.125MXP, or 0313.125VXP be used as direct replacements for 3SB 125-R?

A: Yes. All three Littelfuse parts meet the required electrical parameters (125 mA, 250 V AC), fuse type (cartridge, glass), response time (slow blow), and mechanical package specifications (3AB, 3AG, 1/4" x 1-1/4"). They are compatible with the same holder assemblies.

Q: What is the difference between the three substitute parts?

A: The three Littelfuse parts (0313.125HXP, 0313.125MXP, 0313.125VXP) are electrically and mechanically equivalent. Differences exist in packaging format (all listed as bulk) and may relate to internal manufacturing variations or distribution channels. All meet identical electrical specifications.

Q: Are there differences in breaking capacity between the original and substitute parts?

A: Yes. The 3SB 125-R has a breaking capacity of 200A at rated voltage, while the Littelfuse substitutes have a breaking capacity of 35A. This difference must be evaluated for the specific application to ensure adequate fault protection.

Q: Do the substitute parts require different holders?

A: No. All substitute parts use the same 3AB and 3AG holder packages as the original 3SB 125-R, with identical physical dimensions (1/4" x 1-1/4").

Q: What certifications do the substitute parts carry?

A: The Littelfuse substitute parts carry CE, CSA, and UL certifications. The original 3SB 125-R carries CE, CSA, and cULus certifications. Both sets of certifications are suitable for industrial and consumer applications requiring regulatory compliance.