BK/MDA-1/2 Equivalent & Substitute Parts

Part Overview

The BK/MDA-1/2 is a 500 mA, 250 V AC ceramic cartridge fuse manufactured by Eaton Electronics Division. This component is classified as obsolete and requires a compatible fuse holder (3AB, 3AG format). Due to its obsolete status, direct substitution with active product alternatives is necessary for new designs and ongoing maintenance applications. Substitute parts must maintain electrical equivalence across current rating, voltage rating, response time, and physical dimensions while meeting applicable regulatory compliance standards.

Substiute Parts

BK/MDA-1/2

Eaton - Electronics DivisionIn Stock: 909BK/MDA-1/2 Datasheet

Current PartRFQ

BK/MDA-1/2-R

Eaton - Electronics DivisionIn Stock: 891BK/MDA-1/2-R Datasheet

DirectRFQ

MDA-1/2-R

Eaton - Electronics DivisionIn Stock: 702MDA-1/2-R Datasheet

DirectRFQ

0001.2521

SCHURTER Inc.In Stock: 20440001.2521 Datasheet

DirectRFQ

0326.500MXP

Littelfuse Inc.In Stock: 19400326.500MXP Datasheet

DirectRFQ

0326.500VXP

Littelfuse Inc.In Stock: 9150326.500VXP Datasheet

DirectRFQ

0326012.HXP

Littelfuse Inc.In Stock: 17380326012.HXP Datasheet

SimilarRFQ

0326012.MXP

Littelfuse Inc.In Stock: 240040326012.MXP Datasheet

SimilarRFQ

8020.0603

SCHURTER Inc.In Stock: 14298020.0603 Datasheet

SimilarRFQ

8020.0603.G

SCHURTER Inc.In Stock: 16728020.0603.G Datasheet

SimilarRFQ

0326.500HXP

Littelfuse Inc.In Stock: 14090326.500HXP Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the BK/MDA-1/2 is determined by strict equivalence across the following electrical and mechanical parameters:

Primary Substitution Criteria:

• Current Rating: 500 mA (exact match required)
• Voltage Rating (AC): 250 V (exact match required)
• Response Time: Slow Blow (exact match required)
• Package / Case: 3AB, 3AG, 1/4" x 1-1/4" (exact match required)
• Physical Dimensions: 0.250" Dia x 1.250" L (exact match required)
• Fuse Type: Cartridge, Ceramic (exact match required)

Direct Substitutes are parts that match all primary criteria and are manufactured by Eaton Electronics Division or equivalent manufacturers with active product status.

Parametric Equivalents are parts that match all primary criteria but may have enhanced specifications (such as higher DC voltage rating or improved compliance status) and are manufactured by alternative suppliers.

Similar Parts are listed for reference but do not meet substitution criteria due to different current ratings (12 A vs. 500 mA) and are not suitable for direct replacement.

Parameter Comparison

Engineering Selection Recommendations

Direct Substitutes (Eaton Electronics Division):

The parts BK/MDA-1/2-R and MDA-1/2-R are direct substitutes manufactured by Eaton Electronics Division with active product status. Both parts maintain identical electrical specifications (500 mA, 250 V AC, Slow Blow response) and physical dimensions. Both are ROHS3 compliant, addressing regulatory requirements absent in the obsolete BK/MDA-1/2. These parts are the preferred choice for applications requiring manufacturer continuity and established supply chain relationships.

Parametric Equivalents (Littelfuse Inc.):

The parts 0326.500MXP, 0326.500VXP, and 0326.500HXP are parametric equivalents manufactured by Littelfuse Inc. These ceramic cartridge fuses match all primary substitution criteria (500 mA, 250 V AC, Slow Blow, 3AB/3AG package, identical dimensions). All three parts are active products with ROHS3 compliance and CE, CSA, and UL certifications. The enhanced DC voltage rating (125 V vs. unspecified in the original) provides additional design margin for applications with DC components. These parts are suitable for applications where multi-source qualification is acceptable.

Alternative Fuse Type (SCHURTER Inc.):

The part 0001.2521 is a glass cartridge fuse manufactured by SCHURTER Inc. that matches the 500 mA, 250 V AC, Slow Blow specifications and 3AB/3AG package format. This part differs in fuse construction material (glass vs. ceramic) and includes a specified DC voltage rating (63 V). The glass construction and different material properties may affect thermal and electrical characteristics. This part is suitable only for applications where glass fuse construction is explicitly acceptable or required.

Selection Basis:

Selection among direct substitutes and parametric equivalents should be based on:

• Existing supply chain and qualification status
• Regulatory compliance requirements (ROHS3 compliance is present in all active alternatives)
• Certification requirements (CE, CSA, UL certifications are present in all active alternatives)
• DC voltage application requirements (if DC operation is present, parametric equivalents with 125 V DC rating provide additional margin)

Frequently Asked Questions (FAQ)

Q: Can BK/MDA-1/2-R and MDA-1/2-R be used interchangeably with BK/MDA-1/2?

A: Yes. Both parts are manufactured by Eaton Electronics Division and maintain identical electrical specifications (500 mA, 250 V AC, Slow Blow response) and physical dimensions (0.250" Dia x 1.250" L). Both are compatible with 3AB and 3AG fuse holders. The primary difference is product status: BK/MDA-1/2-R and MDA-1/2-R are active products with ROHS3 compliance, while BK/MDA-1/2 is obsolete and non-compliant.

Q: What is the difference between ceramic and glass fuse construction?

A: The BK/MDA-1/2 is a ceramic cartridge fuse, while the 0001.2521 is a glass cartridge fuse. Both types are cartridge fuses with identical current and voltage ratings and compatible with 3AB/3AG holders. The material difference affects internal arc-quenching characteristics and thermal properties. Substitution between ceramic and glass types is not recommended unless the application explicitly permits alternative fuse construction materials.

Q: Can Littelfuse 0326.500MXP, 0326.500VXP, or 0326.500HXP be used in place of the Eaton BK/MDA-1/2?

A: Yes. All three Littelfuse parts are parametric equivalents that match the primary substitution criteria: 500 mA current rating, 250 V AC voltage rating, Slow Blow response time, 3AB/3AG package format, and identical physical dimensions (0.250" Dia x 1.250" L). All three are active products with ROHS3 compliance and CE, CSA, and UL certifications. The enhanced DC voltage rating (125 V) in these parts provides additional design margin compared to the original specification.

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

A: Yes. All substitute parts listed maintain the 3AB, 3AG package format and physical dimensions (0.250" Dia x 1.250" L or 0.250" Dia x 1.252" L for the SCHURTER glass fuse). All parts are cartridge fuses requiring compatible holders and are mechanically interchangeable within the same holder type.

Q: What certifications do the substitute parts carry?

A: The Eaton parts (BK/MDA-1/2-R and MDA-1/2-R) carry CE, CSA, and UL certifications. The Littelfuse parts (0326.500MXP, 0326.500VXP, 0326.500HXP) carry CE, CSA, and UL certifications. The SCHURTER part (0001.2521) carries cURus certification. All active substitute parts are ROHS3 compliant.

Q: Why do some substitute parts specify a DC voltage rating when the original BK/MDA-1/2 does not?

A: The original BK/MDA-1/2 specification does not include a DC voltage rating. The Littelfuse parametric equivalents (0326.500MXP, 0326.500VXP, 0326.500HXP) specify 125 V DC, and the SCHURTER alternative (0001.2521) specifies 63 V DC. These DC ratings indicate the maximum voltage at which the fuse can safely interrupt DC circuits. If the application includes DC components, selection of parts with specified DC ratings provides additional design margin and safety assurance.

Q: What is the significance of the melting I²t value?

A: The melting I²t value indicates the thermal energy required to melt the fuse element. The original BK/MDA-1/2 specifies 2.3 A²s. Substitute parts show variation in this parameter (ranging from 0.3 to 2.6 A²s depending on construction material and design). This parameter affects the fuse's response to transient overcurrent conditions. For direct substitution, parts with similar I²t values (within the range 2.3 to 2.6 A²s) are preferred to maintain equivalent circuit protection characteristics.

Q: Can the 12 A fuses (0326012.HXP, 0326012.MXP, 8020.0603, 8020.0603.G) be used as substitutes?

A: No. These parts have a current rating of 12 A, which differs significantly from the 500 mA rating of the BK/MDA-1/2. These parts are not suitable for direct substitution and are listed for reference only. Using a 12 A fuse in a circuit designed for 500 mA protection would result in inadequate overcurrent protection.