BK/ETF-2.5 Board Mount Fuse Equivalent & Substitute Parts

Part Overview

The BK/ETF-2.5 is a 2.5 A, 277 V AC board mount fuse manufactured by Eaton - Electronics Division. This component is classified as obsolete, which necessitates identification of equivalent substitute parts for ongoing design support and procurement. The fuse features slow blow response characteristics and is designed for through-hole radial mounting in vertical orientation. Due to its obsolete status, equivalent active alternatives must be evaluated to maintain circuit protection functionality in applications requiring this current and voltage rating.

Substiute Parts

BK/ETF-2.5

Eaton - Electronics DivisionIn Stock: 909BK/ETF-2.5 Datasheet

Current PartRFQ

SR-5-2.5A-BK

Eaton - Electronics DivisionIn Stock: 1030SR-5-2.5A-BK Datasheet

SimilarRFQ

0034.6619

SCHURTER Inc.In Stock: 48810034.6619 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the BK/ETF-2.5 are identified based on the following critical parameters that determine functional equivalence:

Primary Matching Criteria:

• Current Rating: 2.5 A (exact match required)
• Response Time: Slow Blow (exact match required)
• Mounting Type: Through Hole (exact match required)
• Package / Case: Radial, Can, Vertical (exact match required)
• Fuse Type: Board Mount (Cartridge Style Excluded) (exact match required)

Secondary Compatibility Criteria:

• Voltage Rating - AC: Minimum 277 V required for direct substitution
• Operating Temperature Range: Must accommodate -55°C ~ 125°C or equivalent
• Physical Dimensions: Radial can form factor with vertical orientation
• Approval Agencies: Compliance certifications for target application

The identified substitute parts meet the primary matching criteria. However, voltage rating differences and operating temperature variations require engineering evaluation based on specific application requirements.

Parameter Comparison

Engineering Selection Recommendations

SR-5-2.5A-BK Substitution Considerations:

The SR-5-2.5A-BK is an active product from Eaton - Electronics Division with identical current rating and response time characteristics. This part maintains the same manufacturer lineage as the obsolete BK/ETF-2.5. The primary technical difference is the reduced AC voltage rating of 250 V compared to the original 277 V specification. This substitution is applicable only in applications where the circuit operates at 250 V AC or lower. The SR-5-2.5A-BK features expanded approval agency certifications (CCC, cULus, KC-MARK, PSE, SEMKO, VDE) and ROHS3 compliance. The operating temperature range is reduced to -40°C ~ 85°C, which may not accommodate the full -55°C lower temperature specification of the original part. Breaking capacity is reduced to 35 A at rated voltage.

0034.6619 Substitution Considerations:

The 0034.6619 is an active product from SCHURTER Inc. with identical current rating and response time characteristics. This part provides dual voltage rating capability: 250 V AC and 125 V DC. The operating temperature range matches the original specification at -55°C ~ 125°C. The AC voltage rating remains at 250 V, requiring application voltage verification. The breaking capacity is 35 A AC and 50 A DC. Melting I²t is 30, which differs from the original 37. This part carries comprehensive approval agency certifications (CCC, cURus, KC, PSE/JET, VDE) and ROHS3 compliance.

Selection Logic:

Both substitute parts are active products with established supply chains. Selection between SR-5-2.5A-BK and 0034.6619 depends on application voltage requirements and temperature operating range. For applications requiring 277 V AC operation, neither substitute provides direct voltage equivalence. For applications operating at 250 V AC or lower with temperature range -40°C ~ 85°C, SR-5-2.5A-BK is suitable. For applications requiring -55°C ~ 125°C temperature range and dual AC/DC voltage capability, 0034.6619 is suitable.

Frequently Asked Questions (FAQ)

Q: Can SR-5-2.5A-BK be used as a direct replacement for BK/ETF-2.5 in a 277 V AC circuit?

A: No. The SR-5-2.5A-BK has a maximum AC voltage rating of 250 V. Using this part in a 277 V AC circuit exceeds its voltage specification and violates safe operating parameters. The part must only be used in circuits operating at 250 V AC or lower.

Q: What is the impact of the reduced operating temperature range in SR-5-2.5A-BK?

A: The SR-5-2.5A-BK operates from -40°C ~ 85°C, compared to the original BK/ETF-2.5 range of -55°C ~ 125°C. If the application requires operation below -40°C or above 85°C, this substitute is not suitable. The 0034.6619 maintains the full -55°C ~ 125°C range.

Q: Are the physical dimensions of substitute parts compatible with the original PCB layout?

A: The substitute parts have slightly larger dimensions. BK/ETF-2.5 is 0.329" Dia x 0.303" H, while both substitutes are 0.335" Dia x 0.319" H or 0.335" Dia x 0.335" H. PCB footprint verification is required to confirm mechanical compatibility.

Q: What does the reduced breaking capacity in substitute parts mean?

A: The BK/ETF-2.5 has a breaking capacity of 100 A at rated voltage, while both substitutes have 35 A AC. Breaking capacity indicates the maximum fault current the fuse can safely interrupt. Lower breaking capacity may be insufficient for circuits with high fault current potential. Application fault current analysis is required.

Q: Can 0034.6619 be used in DC applications?

A: Yes. The 0034.6619 is rated for 125 V DC operation, providing dual AC/DC capability. The BK/ETF-2.5 and SR-5-2.5A-BK do not specify DC voltage ratings. If DC operation is required, 0034.6619 is the only substitute with explicit DC rating.

Q: What is the significance of the different Melting I²t values?

A: Melting I²t characterizes the thermal energy required to melt the fuse element. BK/ETF-2.5 has I²t of 37, SR-5-2.5A-BK has 45, and 0034.6619 has 30. These differences affect the fuse's response to transient overcurrent conditions. Application transient current profiles must be evaluated for compatibility.

Q: Are all substitute parts RoHS compliant?

A: The BK/ETF-2.5 does not specify RoHS status. Both SR-5-2.5A-BK and 0034.6619 are ROHS3 compliant. If RoHS compliance is required for the application, both substitutes meet this requirement.

Q: Which approval agencies are common to all parts?

A: SEMKO and VDE certifications are present in the substitute parts. The original BK/ETF-2.5 carries SEMKO and UL approvals. Specific application regulatory requirements determine which certifications are necessary.