Equivalent & Substitute Parts for BK/MDL-2-1/2EX-R

Part Overview

The BK/MDL-2-1/2EX-R is a 2.5 A, 250 V AC/DC slow-blow glass cartridge fuse manufactured by Eaton - Electronics Division. This fuse is designed for use in 3AB and 3AG holders with dimensions of 1/4" x 1-1/4" (6.35mm x 31.75mm). The part is currently active in production with 747 pieces in stock. Equivalent and substitute parts are identified based on matching electrical ratings, mechanical form factors, and approval certifications to ensure direct interchangeability in circuit protection applications.

Substiute Parts

BK/MDL-2-1/2EX-R

Eaton - Electronics DivisionIn Stock: 831BK/MDL-2-1/2EX-R Datasheet

Current PartRFQ

BK/MDL-2-1/2-R

Eaton - Electronics DivisionIn Stock: 833BK/MDL-2-1/2-R Datasheet

Parametric EquivalentRFQ

BK/MDQ-2-1/2

Eaton - Electronics DivisionIn Stock: 1064BK/MDQ-2-1/2 Datasheet

Parametric EquivalentRFQ

MDQ-2-1/2

Eaton - Electronics DivisionIn Stock: 749MDQ-2-1/2 Datasheet

Parametric EquivalentRFQ

0034.3421

SCHURTER Inc.In Stock: 10550034.3421 Datasheet

Parametric EquivalentRFQ

031302.5HXP

Littelfuse Inc.In Stock: 1258031302.5HXP Datasheet

Parametric EquivalentRFQ

031302.5MXP

Littelfuse Inc.In Stock: 9261031302.5MXP Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the BK/MDL-2-1/2EX-R are classified based on the following critical parameters that determine functional interchangeability:

Primary Matching Criteria:

• Current Rating: 2.5 A
• Voltage Rating (AC): 250 V
• Fuse Type: Cartridge, Glass
• Response Time: Slow Blow
• Package / Case: 3AB, 3AG, 1/4" x 1-1/4"
• Size / Dimension: 0.250" Dia x 1.250" L (6.35mm x 31.75mm)
• Mounting Type: Requires Holder

Secondary Considerations:

• Breaking Capacity @ Rated Voltage
• DC Cold Resistance
• Approval Agency certifications
• Product Status (Active vs. Obsolete)
• RoHS compliance status

All identified substitutes meet the primary matching criteria. Variations in breaking capacity, resistance, and compliance certifications are noted in the parameter comparison table to support engineering selection decisions.

Parameter Comparison

Engineering Selection Recommendations

Tier 1 - Direct Equivalents (Highest Compatibility):

BK/MDL-2-1/2-R and BK/MDQ-2-1/2 are direct parametric equivalents to the BK/MDL-2-1/2EX-R. Both are manufactured by Eaton - Electronics Division and maintain identical electrical ratings, response characteristics, and mechanical form factors. BK/MDL-2-1/2-R offers expanded approval certifications (CE, CSA, UL) compared to the original part. Both parts are active in production.

Tier 2 - Functional Equivalents (Electrical Match, Reduced Breaking Capacity):

MDQ-2-1/2 is functionally equivalent with matching electrical ratings and form factor. This part has a reduced breaking capacity of 35 A compared to the original 100 A specification. Selection of this part requires verification that the application does not require the higher breaking capacity rating.

Tier 3 - Cross-Manufacturer Equivalents (Active Production):

031302.5HXP and 031302.5MXP, manufactured by Littelfuse Inc., are parametric equivalents with identical electrical ratings, response time, and mechanical dimensions. Both parts feature expanded approval certifications (CE, CSA, K-MARK, PSE, UL) and are actively produced. DC cold resistance is 0.0811 Ohms, which is equivalent to the original specification.

Tier 4 - Obsolete Substitute (Not Recommended for New Designs):

0034.3421, manufactured by SCHURTER Inc., meets electrical and mechanical specifications but is marked as obsolete. This part has a reduced breaking capacity of 35 A and limited approval certifications (CSA only). Use of this part is not recommended for new circuit designs or long-term applications.

Frequently Asked Questions (FAQ)

Q: Can BK/MDL-2-1/2-R be used as a direct replacement for BK/MDL-2-1/2EX-R?

A: Yes. BK/MDL-2-1/2-R is a direct parametric equivalent manufactured by the same supplier (Eaton - Electronics Division) with identical electrical ratings (2.5 A, 250 V AC), response time (Slow Blow), mechanical dimensions (1/4" x 1-1/4"), and breaking capacity (100 A). The part is actively produced and includes additional CE certification.

Q: What is the difference between BK/MDQ-2-1/2 and MDQ-2-1/2?

A: Both parts are manufactured by Eaton - Electronics Division with identical electrical ratings and mechanical form factors. The primary difference is breaking capacity: BK/MDQ-2-1/2 has 100 A breaking capacity, while MDQ-2-1/2 has 35 A breaking capacity. Selection depends on the application's fault current requirements.

Q: Are Littelfuse 031302.5HXP and 031302.5MXP interchangeable?

A: Yes. Both Littelfuse parts are parametric equivalents with identical electrical ratings (2.5 A, 250 V AC), response time (Slow Blow), mechanical dimensions (1/4" x 1-1/4"), breaking capacity (100 A), and DC cold resistance (0.0811 Ohms). Both are actively produced and carry identical approval certifications.

Q: Why is 0034.3421 listed as obsolete?

A: The SCHURTER Inc. part 0034.3421 is marked as obsolete in the manufacturer's product status. While it meets the electrical and mechanical specifications, it has reduced breaking capacity (35 A) and limited approval certifications (CSA only). New designs should use active production alternatives.

Q: What are the key parameters that determine if a fuse can substitute for BK/MDL-2-1/2EX-R?

A: The critical parameters are: Current Rating (2.5 A), Voltage Rating (250 V AC), Fuse Type (Cartridge, Glass), Response Time (Slow Blow), Package / Case (3AB, 3AG), and mechanical dimensions (1/4" x 1-1/4"). All identified substitutes match these parameters. Breaking capacity and approval certifications are secondary considerations based on application requirements.

Q: Can I use a substitute fuse with lower breaking capacity?

A: Substitutes with lower breaking capacity (35 A vs. 100 A) meet the electrical and mechanical specifications but may not provide equivalent protection in high fault-current environments. Application-specific fault current analysis is required to determine if reduced breaking capacity is acceptable.

Q: Are all substitute parts RoHS compliant?

A: RoHS compliance varies among substitutes. BK/MDL-2-1/2-R, 031302.5HXP, and 031302.5MXP are ROHS3 compliant. BK/MDQ-2-1/2 and MDQ-2-1/2 are RoHS non-compliant. 0034.3421 is ROHS3 compliant. Verify RoHS requirements for your specific application before selection.