Equivalent & Substitute Parts for BK/EFF-2.5 Board Mount Fuse

Part Overview

The BK/EFF-2.5 is a 2.5 A 250 V AC/DC board mount fuse manufactured by Eaton - Electronics Division. This radial, can-style through-hole fuse features fast-blow response characteristics and is designed for PCB integration in electronic equipment requiring overcurrent protection. The part is currently classified as obsolete, necessitating identification of active equivalent alternatives that maintain electrical and mechanical compatibility with existing circuit designs.

Substiute Parts

BK/EFF-2.5

Eaton - Electronics DivisionIn Stock: 980BK/EFF-2.5 Datasheet

Current PartRFQ

SR-5F-2.5A-BK

Eaton - Electronics DivisionIn Stock: 898SR-5F-2.5A-BK Datasheet

SimilarRFQ

MRF 2.5-AMMO

Bel Fuse Inc.In Stock: 820MRF 2.5-AMMO Datasheet

DirectRFQ

MRF 2.5-BULK

Bel Fuse Inc.In Stock: 7319MRF 2.5-BULK Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the BK/EFF-2.5 is determined by strict alignment of the following parameters:

• Current Rating: Must be 2.5 A
• Voltage Rating (AC): Must be 250 V
• Response Time: Must be Fast Blow
• Mounting Type: Must be Through Hole
• Fuse Type: Must be Board Mount (Cartridge Style Excluded)
• Package Style: Must be Radial, Can, Vertical
• Operating Temperature Range: Must encompass or match -55°C ~ 125°C

All identified substitute parts meet these core electrical and mechanical criteria. Variations in secondary parameters such as breaking capacity, melting I²t, DC cold resistance, and approval agencies do not disqualify substitution but are documented for engineering reference.

Parameter Comparison

Engineering Selection Recommendations

SR-5F-2.5A-BK (Eaton - Electronics Division)

This substitute maintains manufacturer continuity with the original BK/EFF-2.5. It is an active product with current production status. The physical dimensions differ slightly (0.335" Dia x 0.319" H versus 0.329" Dia x 0.303" H), requiring PCB footprint verification before implementation. The operating temperature range is -40°C ~ 125°C, which does not extend to the lower -55°C limit of the original part. Selection of this substitute is appropriate for applications operating within the -40°C ~ 125°C envelope.

MRF 2.5-AMMO (Bel Fuse Inc.)

This substitute is an active product with identical physical dimensions to the original BK/EFF-2.5 (0.329" Dia x 0.303" H). It maintains the full operating temperature range of -55°C ~ 125°C. The breaking capacity is 35A compared to the original 50A. Approval certifications include AEC-Q200, CE, CSA, cULus, PSE, SEMKO, and VDE, providing broad regulatory coverage. Packaging is Tape & Box (TB). This substitute is suitable for direct replacement in applications requiring the original temperature range and dimensional compatibility.

MRF 2.5-BULK (Bel Fuse Inc.)

This substitute is functionally identical to MRF 2.5-AMMO with the same electrical specifications, temperature range, and physical dimensions. The distinction is packaging format (Bulk versus Tape & Box). This substitute is appropriate for high-volume production environments where bulk packaging is preferred. Approval certifications and compliance status are identical to MRF 2.5-AMMO.

Frequently Asked Questions (FAQ)

Q: Can SR-5F-2.5A-BK be used as a direct replacement for BK/EFF-2.5 in all applications?

A: SR-5F-2.5A-BK meets all core electrical parameters but has a reduced operating temperature range (-40°C ~ 125°C versus -55°C ~ 125°C) and slightly larger physical dimensions (0.335" Dia x 0.319" H). Verification of PCB footprint clearance and operating temperature requirements is necessary before selection.

Q: What is the difference between MRF 2.5-AMMO and MRF 2.5-BULK?

A: Both parts are electrically and mechanically identical. The difference is packaging: MRF 2.5-AMMO is supplied in Tape & Box format, while MRF 2.5-BULK is supplied in bulk packaging. Selection depends on production volume and inventory management requirements.

Q: Are the Bel Fuse MRF 2.5 series parts suitable for applications requiring -55°C operation?

A: Yes. Both MRF 2.5-AMMO and MRF 2.5-BULK maintain the full operating temperature range of -55°C ~ 125°C, matching the original BK/EFF-2.5 specification.

Q: What is the significance of the breaking capacity difference between BK/EFF-2.5 (50A) and MRF 2.5 series (35A)?

A: Breaking capacity indicates the maximum fault current the fuse can safely interrupt. The MRF 2.5 series has a lower breaking capacity of 35A. Applications requiring 50A breaking capacity must use SR-5F-2.5A-BK or verify that circuit fault currents do not exceed 35A.

Q: Which substitute has the broadest regulatory approvals?

A: MRF 2.5-AMMO and MRF 2.5-BULK both carry AEC-Q200, CE, CSA, cULus, PSE, SEMKO, and VDE certifications, providing the most comprehensive regulatory coverage for global applications.

Q: Are there RoHS compliance considerations for these substitutes?

A: SR-5F-2.5A-BK status is not specified in provided data. MRF 2.5-AMMO and MRF 2.5-BULK are both ROHS3 Compliant. Applications requiring RoHS compliance should select MRF series parts.