3SBP 125-R Equivalent & Substitute Parts

Part Overview

The 3SBP 125-R is a 125 mA, 250 V AC/DC slow-blow glass cartridge fuse manufactured by Bel Fuse Inc. in the 3AB/3AG form factor (1/4" x 1-1/4" axial). This part is classified as obsolete, necessitating identification of active equivalent alternatives that maintain identical electrical and mechanical specifications for direct circuit board replacement.

Substiute Parts

3SBP 125-R

Bel Fuse Inc.In Stock: 6503SBP 125-R Datasheet

Current PartRFQ

0315.125HXP

Littelfuse Inc.In Stock: 9080315.125HXP Datasheet

DirectRFQ

0315.125MXP

LittelfuseIn Stock: 9730315.125MXP Datasheet

DirectRFQ

0315.125VXP

Littelfuse Inc.In Stock: 8540315.125VXP Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 3SBP 125-R is determined by strict equivalence across the following parameters:

• 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" (Axial) (exact match required)
• Mounting Type: Through Hole (exact match required)
• Operating Temperature Range: -55°C ~ 125°C (exact match required)
• RoHS Compliance: ROHS3 Compliant (exact match required)

All three substitute parts from Littelfuse Inc. (0315.125HXP, 0315.125MXP, 0315.125VXP) meet these criteria and are classified as active products with current manufacturing status.

Parameter Comparison

Engineering Selection Recommendations

All three Littelfuse 315 series substitutes (0315.125HXP, 0315.125MXP, 0315.125VXP) are direct functional equivalents to the obsolete 3SBP 125-R. Selection among these three active alternatives is based on availability and packaging preference, as all three maintain identical electrical specifications and certifications (CE, CSA, UL). The transition from the Bel Fuse part to any of these Littelfuse alternatives requires no circuit redesign or thermal management modifications, as operating temperature ranges and electrical ratings are fully compatible.

Frequently Asked Questions (FAQ)

Q: Can the Littelfuse 0315.125HXP, 0315.125MXP, or 0315.125VXP be used interchangeably with the 3SBP 125-R?

A: Yes. All three Littelfuse parts are direct substitutes. They share identical current ratings (125 mA), voltage ratings (250 V AC), fuse type (cartridge, glass), response time (slow blow), package dimensions (3AB, 3AG, 1/4" x 1-1/4" axial), and operating temperature range (-55°C ~ 125°C). Through-hole mounting is identical across all parts.

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

A: The three Littelfuse substitutes (0315.125HXP, 0315.125MXP, 0315.125VXP) are electrically and mechanically identical. Differences exist only in internal construction characteristics (breaking capacity and melting I²t values) that do not affect their function as direct replacements for the 3SBP 125-R in standard circuit protection applications.

Q: Are the substitute parts RoHS compliant?

A: Yes. All three Littelfuse substitutes are ROHS3 compliant, matching the compliance status of the original 3SBP 125-R.

Q: Do the substitute parts have the same certifications as the original part?

A: The substitute parts carry CE, CSA, and UL certifications. The original 3SBP 125-R carries CE, CSA, and cULus certifications. Both certification sets are acceptable for equivalent circuit protection applications.

Q: Are physical dimensions identical between the original and substitute parts?

A: Dimensions are functionally equivalent. The original 3SBP 125-R measures 0.272" Dia x 1.280" L (6.90mm x 32.50mm). The Littelfuse substitutes measure 0.275" Dia x 1.275" L (6.99mm x 32.39mm). These minor variations remain within the 3AB/3AG form factor tolerance and do not affect through-hole mounting compatibility.