BK/MDA-12 Equivalent & Substitute Parts

Part Overview

The BK/MDA-12 is a 12 A, 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 product status, direct replacement with active production equivalents is necessary for new designs and ongoing system maintenance. Substitute parts maintain identical electrical and mechanical specifications while offering improved availability and compliance with current regulatory standards.

Key Parameters

Parameter	Value
Current Rating	12 A
Voltage Rating - AC	250 V
Fuse Type	Cartridge, Ceramic
Response Time	Slow Blow
Package / Case	3AB, 3AG, 1/4" x 1-1/4" (6.35mm x 31.75mm)
Mounting Type	Requires Holder
Breaking Capacity @ Rated Voltage	750 A

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict equivalence across the following parameters: current rating (12 A), AC voltage rating (250 V), fuse type (cartridge ceramic), response time (slow blow), and physical package dimensions (3AB, 3AG, 1/4" x 1-1/4"). All substitute parts listed maintain these core specifications.

Substitute parts are grouped into two categories:

Direct Eaton Equivalents: BK/MDA-12-R and MDA-12-R are active production variants of the original BK/MDA-12. These parts are manufactured by Eaton - Electronics Division and provide direct functional replacement with improved product status and regulatory compliance.

Cross-Manufacturer Alternatives: Littelfuse Inc. parts (0326012.MXDP, 0326012.HXP, 0326012.MXCCP, 0326012.MXP, 0326012.VXP) meet the core electrical and mechanical requirements. These parts are functionally equivalent for AC applications at 250 V and 12 A. Littelfuse alternatives provide extended DC voltage ratings (60 V or 125 V) and broader operating temperature ranges (-55°C to 125°C), which do not restrict their use in applications requiring only AC operation.

Parameter Comparison

Part Number	Manufacturer	Current Rating (A)	Voltage AC (V)	Voltage DC (V)	Response Time	Breaking Capacity @ Rated Voltage	Product Status	RoHS Status	Approval Agency
BK/MDA-12	Eaton	12	250	—	Slow Blow	750 A	Obsolete	Non-compliant	CSA, UL
BK/MDA-12-R	Eaton	12	250	—	Slow Blow	750 A	Active	ROHS3 Compliant	CE, CSA, UL
MDA-12-R	Eaton	12	250	—	Slow Blow	750 A	Active	ROHS3 Compliant	CSA, UL
BK/MDA-12NR	Eaton	12	250	—	Slow Blow	750 A	Active	ROHS3 Compliant	CE, CSA, UL
0326012.MXDP	Littelfuse	12	250	60	Slow Blow	400 A AC, 500 A DC	Active	ROHS3 Compliant	CE, CSA, UL
0326012.HXP	Littelfuse	12	250	60	Slow Blow	400 A AC, 500 A DC	Active	ROHS3 Compliant	CE, CSA, K-MARK, PSE, UL
0326012.MXCCP	Littelfuse	12	250	60	Slow Blow	400 A AC, 500 A DC	Active	ROHS3 Compliant	CE, CSA, K-MARK, PSE, UL
0326012.MXP	Littelfuse	12	250	60	Slow Blow	400 A AC, 500 A DC	Active	ROHS3 Compliant	CE, CSA, K-MARK, PSE, UL
0326012.VXP	Littelfuse	12	250	125	Slow Blow	400 A AC, 600 A DC	Active	ROHS3 Compliant	CE, CSA, KC, PSE, UL

Engineering Selection Recommendations

Primary Recommendation: BK/MDA-12-R or BK/MDA-12NR are the preferred substitutes for the obsolete BK/MDA-12. Both are manufactured by Eaton - Electronics Division, ensuring design continuity and supply chain consistency. These parts are active production items with ROHS3 compliance and CE certification in addition to CSA and UL approvals held by the original part.

Secondary Recommendation: MDA-12-R provides an alternative Eaton solution with identical electrical specifications and active product status. This part carries ROHS3 compliance and CSA/UL certification.

Cross-Manufacturer Alternatives: Littelfuse parts 0326012.MXDP, 0326012.HXP, 0326012.MXCCP, 0326012.MXP, and 0326012.VXP are functionally equivalent for 250 V AC, 12 A applications. All Littelfuse alternatives are active production items with ROHS3 compliance and comprehensive international certifications (CE, CSA, UL, K-MARK, PSE). The extended DC voltage ratings and operating temperature ranges of Littelfuse parts do not restrict their application in AC-only circuits and provide additional design flexibility for future modifications.

Selection between Eaton and Littelfuse alternatives should be based on supply chain requirements, existing qualification documentation, and system design specifications.

Frequently Asked Questions (FAQ)

Q: Can BK/MDA-12-R directly replace the obsolete BK/MDA-12?

A: Yes. BK/MDA-12-R is an active production equivalent manufactured by Eaton - Electronics Division with identical electrical ratings (12 A, 250 V AC), fuse type (ceramic cartridge), response time (slow blow), and physical dimensions (3AB, 3AG, 1/4" x 1-1/4"). The part is compatible with all existing 3AB/3AG fuse holders designed for the original BK/MDA-12.

Q: What is the difference between BK/MDA-12-R and MDA-12-R?

A: Both parts are manufactured by Eaton and share identical electrical specifications and physical dimensions. The primary difference is the product designation format. Both are active production items with ROHS3 compliance. MDA-12-R carries CSA and UL certifications, while BK/MDA-12-R includes CE certification in addition to CSA and UL.

Q: Are Littelfuse parts (0326012 series) compatible with the BK/MDA-12?

A: Yes. Littelfuse parts 0326012.MXDP, 0326012.HXP, 0326012.MXCCP, 0326012.MXP, and 0326012.VXP are mechanically and electrically compatible for 250 V AC, 12 A applications. All parts use the same 3AB, 3AG cartridge format and fit standard fuse holders. The extended DC voltage ratings (60 V or 125 V) and operating temperature ranges do not affect AC circuit operation.

Q: What is the difference between 0326012.MXDP, 0326012.HXP, 0326012.MXCCP, 0326012.MXP, and 0326012.VXP?

A: All five Littelfuse parts maintain the same 12 A, 250 V AC rating and 3AB, 3AG package format. The primary differences are DC voltage ratings and melting I²t characteristics. 0326012.MXDP, 0326012.HXP, 0326012.MXCCP, and 0326012.MXP are rated for 60 V DC. 0326012.VXP is rated for 125 V DC. For AC-only applications, these differences do not affect circuit performance.

Q: Is the BK/MDA-12 still available for purchase?

A: The BK/MDA-12 is classified as obsolete. Active production alternatives from Eaton (BK/MDA-12-R, MDA-12-R, BK/MDA-12NR) and Littelfuse (0326012 series) are currently available and recommended for new designs and replacement applications.

Q: Do all substitute parts meet the same regulatory certifications as the original BK/MDA-12?

A: The original BK/MDA-12 carries CSA and UL certifications. All substitute parts maintain CSA and UL approvals. Eaton alternatives (BK/MDA-12-R, BK/MDA-12NR) add CE certification. Littelfuse alternatives include CE, CSA, UL, and additional international certifications (K-MARK, PSE, KC). All substitute parts are ROHS3 compliant, whereas the original BK/MDA-12 is non-compliant.

Q: Can I use a substitute part with a higher DC voltage rating in an AC-only circuit?

A: Yes. Littelfuse parts with 60 V DC or 125 V DC ratings are fully compatible with AC circuits rated at 250 V. The DC voltage rating does not restrict AC operation. These parts are suitable for applications requiring only AC protection.

Q: What is the physical compatibility requirement for these fuse cartridges?

A: All parts listed require a compatible fuse holder rated for 3AB or 3AG cartridge format. The physical dimensions are standardized at 1/4" diameter by 1-1/4" length (6.35mm x 31.75mm). Any holder designed for 3AB, 3AG cartridges will accommodate all substitute parts listed.

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