5SFP 1.25 Equivalent & Substitute Parts

Part Overview

The 5SFP 1.25 is a 1.25 A 250 V AC DC fuse cartridge with glass construction, designed for through-hole mounting in 5mm x 20mm (axial) package configuration. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing system maintenance and new design implementations. The fast-blow response characteristic and 35A breaking capacity at rated voltage define its application scope in circuit protection.

Substiute Parts

5SFP 1.25

Bel Fuse Inc.In Stock: 9255SFP 1.25 Datasheet

Current PartRFQ

5SFP 1.25-R

Bel Fuse Inc.In Stock: 17595SFP 1.25-R Datasheet

DirectRFQ

5MFP 1.25-R

Bel Fuse Inc.In Stock: 19475MFP 1.25-R Datasheet

Parametric EquivalentRFQ

0034.1517.PT

SCHURTER Inc.In Stock: 40070034.1517.PT Datasheet

DirectRFQ

02171.25MXEP

Littelfuse Inc.In Stock: 142602171.25MXEP Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict equivalence across the following parameters: current rating (1.25 A), voltage rating (250 V AC), fuse type (cartridge glass), package dimensions (5mm x 20mm axial), response time (fast blow), and mounting type (through hole). All listed substitute parts meet these core electrical and mechanical requirements.

The substitute parts are grouped into two categories:

Direct Manufacturer Equivalents (Same Series): Parts 5SFP 1.25-R and 5MFP 1.25-R from Bel Fuse Inc. maintain identical electrical ratings and package specifications. The 5SFP 1.25-R is the direct active-status equivalent of the obsolete 5SFP 1.25. The 5MFP 1.25-R is a parametric equivalent from the same manufacturer with identical current and voltage ratings but different melting I²t and breaking capacity characteristics.

Cross-Manufacturer Equivalents: Parts 0034.1517.PT (SCHURTER Inc.) and 02171.25MXEP (Littelfuse Inc.) provide functional equivalence across manufacturers while maintaining the same electrical ratings, package type, and response characteristics.

Parameter Comparison

Engineering Selection Recommendations

Primary Recommendation: The 5SFP 1.25-R from Bel Fuse Inc. is the direct active-status equivalent of the obsolete 5SFP 1.25. It maintains identical electrical ratings, package specifications, and melting I²t characteristics. This part carries ROHS3 compliance and expanded approval certifications (CCC, CE, CSA, cULus, IMQ, SEMKO, VDE) compared to the original part.

Secondary Recommendation: The 02171.25MXEP from Littelfuse Inc. provides cross-manufacturer equivalence with comprehensive international certifications (BSI, CE, CCC, CSA, KC, PSE, SEMKO, UR, VDE) and ROHS3 compliance. Melting I²t of 2.23 is within acceptable tolerance of the original 2.5 specification.

Alternative Consideration: The 5MFP 1.25-R from Bel Fuse Inc. meets all electrical and mechanical requirements but features a higher breaking capacity (200 A versus 35 A) and lower melting I²t (1.5 versus 2.5). This part is suitable for applications where enhanced breaking capacity is beneficial and faster response time is acceptable.

Cross-Manufacturer Option: The 0034.1517.PT from SCHURTER Inc. maintains equivalent electrical ratings and breaking capacity. Physical dimensions show minor variation (5.40mm x 22.50mm versus 5.50mm x 21.00mm), requiring verification of mechanical fit in existing footprints.

All substitute parts are currently in active production status with available inventory, ensuring supply chain continuity.

Frequently Asked Questions (FAQ)

Q: Can the 5SFP 1.25-R be used as a direct replacement for the obsolete 5SFP 1.25?

A: Yes. The 5SFP 1.25-R is the direct active-status equivalent with identical current rating (1.25 A), voltage rating (250 V), package dimensions (5mm x 20mm), response time (fast blow), and melting I²t (2.5). It provides improved compliance status (ROHS3) and expanded certifications.

Q: What is the difference between the 5SFP 1.25-R and 5MFP 1.25-R?

A: Both parts share identical current, voltage, and package specifications. The 5MFP 1.25-R has a higher breaking capacity (200 A versus 35 A) and lower melting I²t (1.5 versus 2.5), resulting in faster response characteristics. Selection depends on application requirements for breaking capacity and response speed.

Q: Are there physical dimension differences between substitute parts?

A: The 0034.1517.PT from SCHURTER Inc. has dimensions of 5.40mm x 22.50mm compared to the standard 5.50mm x 21.00mm. The 02171.25MXEP from Littelfuse Inc. measures 5.80mm x 22.50mm. These variations require verification of mechanical fit in existing circuit board footprints and holder designs.

Q: Which substitute part has the broadest international certification coverage?

A: The 02171.25MXEP from Littelfuse Inc. carries certifications from BSI, CE, CCC, CSA, KC, PSE, SEMKO, UR, and VDE, providing the most comprehensive international approval coverage.

Q: Are all substitute parts RoHS compliant?

A: Yes. All active substitute parts (5SFP 1.25-R, 5MFP 1.25-R, 0034.1517.PT, and 02171.25MXEP) are ROHS3 compliant. The original 5SFP 1.25 is RoHS non-compliant.

Q: What is the significance of melting I²t values in fuse selection?

A: Melting I²t determines the thermal energy required to melt the fuse element. Lower values indicate faster response to overcurrent conditions. The original 5SFP 1.25 has a melting I²t of 2.5. Substitute parts range from 1.5 to 2.5, with values closer to the original providing more similar response characteristics.