BK/MDA-1/4 Ceramic Cartridge Fuse Equivalent & Substitute Parts

Part Overview

The BK/MDA-1/4 is a 250 mA, 250 V AC ceramic cartridge fuse manufactured by Eaton - Electronics Division. This component is classified as obsolete, requiring identification of active equivalent alternatives for continued system support and procurement. The fuse operates with slow-blow response characteristics and requires a 3AB or 3AG holder for installation. Substitution is necessary due to the obsolete product status, which limits long-term availability and supply chain reliability.

Substiute Parts

BK/MDA-1/4

Eaton - Electronics DivisionIn Stock: 956BK/MDA-1/4 Datasheet

Current PartRFQ

BK/MDA-1/4-R

Eaton - Electronics DivisionIn Stock: 1534BK/MDA-1/4-R Datasheet

DirectRFQ

MDA-1/4-R

Eaton - Electronics DivisionIn Stock: 676MDA-1/4-R Datasheet

DirectRFQ

0326.250HXP

Littelfuse Inc.In Stock: 11290326.250HXP Datasheet

DirectRFQ

0326.250MXP

Littelfuse Inc.In Stock: 17210326.250MXP Datasheet

DirectRFQ

0326.250VXP

Littelfuse Inc.In Stock: 12460326.250VXP Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict alignment with the following critical parameters:

Primary Substitution Criteria:

• Current Rating: 250 mA (exact match required)
• Voltage Rating - AC: 250 V (exact match required)
• Fuse Type: Cartridge, Ceramic (exact match required)
• Response Time: Slow Blow (exact match required)
• Package / Case: 3AB, 3AG, 1/4" x 1-1/4" (exact match required)
• Mounting Type: Requires Holder (exact match required)

All substitute parts listed meet these mandatory criteria. Secondary parameters such as breaking capacity, melting I²t, DC resistance, and compliance certifications may vary within acceptable engineering tolerances for the same functional category.

Parameter Comparison

Engineering Selection Recommendations

Eaton MDA Series (Preferred for Direct Replacement):

BK/MDA-1/4-R and MDA-1/4-R are active-status alternatives from Eaton's MDA series. Both parts maintain identical electrical specifications to the obsolete BK/MDA-1/4 and are ROHS3 compliant. BK/MDA-1/4-R is available in bulk packaging with 1476 units in stock. MDA-1/4-R is also available in bulk with 665 units in stock. Both carry CE, CSA, and UL approvals. These options provide the most direct substitution path with no functional deviation.

Littelfuse 326 Series (Cross-Manufacturer Alternative):

The 0326.250HXP, 0326.250MXP, and 0326.250VXP are functionally equivalent alternatives from Littelfuse Inc. All three parts meet the primary substitution criteria and are active-status products with ROHS3 compliance. These parts provide enhanced DC voltage rating (125 V DC) and higher breaking capacity (100A AC, 10kA DC) compared to the original specification. All three carry CE, CSA, and UL approvals. Littelfuse inventory levels are robust: 0326.250HXP (1035 units), 0326.250MXP (1651 units), and 0326.250VXP (1149 units).

Compliance Considerations:

The original BK/MDA-1/4 is RoHS non-compliant. All substitute parts listed are ROHS3 compliant, meeting current regulatory requirements for new designs and procurement cycles.

Frequently Asked Questions (FAQ)

Q: Can BK/MDA-1/4-R directly replace the obsolete BK/MDA-1/4?

A: Yes. BK/MDA-1/4-R is an active-status equivalent from Eaton with identical electrical specifications (250 mA, 250 V AC, slow-blow response, 3AB/3AG package). The primary difference is ROHS3 compliance and improved melting I²t characteristic (0.28 vs. 0.68).

Q: What is the difference between BK/MDA-1/4-R and MDA-1/4-R?

A: Both are Eaton MDA series fuses with identical electrical and mechanical specifications. The designation difference reflects internal Eaton part numbering conventions. Both are active-status, ROHS3 compliant, and carry the same approvals (CE, CSA, UL).

Q: Can Littelfuse 326 series parts replace Eaton MDA series fuses?

A: Yes, within the specified parameters. The 0326.250HXP, 0326.250MXP, and 0326.250VXP meet all primary substitution criteria (250 mA, 250 V AC, slow-blow, 3AB/3AG package). The Littelfuse parts provide additional DC voltage rating (125 V) and higher breaking capacity, making them suitable for applications requiring enhanced performance margins.

Q: Are all substitute parts compatible with existing 3AB and 3AG holders?

A: Yes. All substitute parts maintain the identical physical dimensions (0.250" Dia x 1.250" L / 6.35mm x 31.75mm) and package designation (3AB, 3AG), ensuring mechanical compatibility with existing holder installations.

Q: What certifications do the substitute parts carry?

A: Eaton MDA series substitutes (BK/MDA-1/4-R, MDA-1/4-R) carry CE, CSA, and UL approvals. Littelfuse 326 series substitutes (0326.250HXP, 0326.250MXP, 0326.250VXP) also carry CE, CSA, and UL approvals. All are ROHS3 compliant.

Q: Why do Littelfuse parts have different melting I²t values?

A: Melting I²t (0.432 for Littelfuse vs. 0.28 for Eaton MDA-R series) reflects different ceramic formulations and thermal characteristics. Both values fall within acceptable ranges for 250 mA slow-blow fuses and do not affect functional compatibility in standard applications.

Q: Which substitute offers the best inventory availability?

A: Littelfuse 0326.250MXP has the highest inventory level at 1651 units. Eaton BK/MDA-1/4-R follows with 1476 units. All substitutes maintain sufficient stock for immediate procurement.