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

Part Overview

The BK/MDA-1 is a 1 A, 250 V AC ceramic fuse cartridge manufactured by Eaton Electronics Division. This component is classified as obsolete and requires a compatible fuse holder (3AB or 3AG type) for installation. The slow-blow response characteristic provides circuit protection for applications requiring delayed trip functionality. Due to its obsolete product status, equivalent substitute parts from active product lines are available to ensure continued circuit protection capability and supply chain continuity.

Key Parameters

Parameter	Value
Current Rating	1 A
Voltage Rating (AC)	250 V
Fuse Type	Cartridge, Ceramic
Response Time	Slow Blow
Package / Case	3AB, 3AG, 1/4" x 1-1/4"
Physical Dimensions	0.250" Dia x 1.250" L (6.35mm x 31.75mm)
Breaking Capacity @ Rated Voltage	35 A
Mounting Type	Requires Holder

Substitute Part Grouping Explanation

Substitution eligibility for the BK/MDA-1 ceramic fuse cartridge is determined by the following critical parameters:

Mandatory Matching Parameters:

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

Substitute parts are grouped into two categories:

Category 1: Direct Eaton Replacements (Active Status) Parts BK/MDA-1-R and MDA-1-R are current production equivalents from Eaton Electronics Division. These parts maintain identical electrical and mechanical specifications to the original BK/MDA-1 while offering improved compliance status and enhanced availability.

Category 2: Cross-Manufacturer Alternatives Parts 0326001.HXP, 0326001.MXP, and 0326001.VXP (Littelfuse Inc., Series 326) and part 0001.2524 (SCHURTER Inc., Series SPT 6.3x32) provide functional equivalence with identical current, voltage, and package specifications. These alternatives differ in fuse material composition (glass vs. ceramic), DC voltage rating, and thermal characteristics but maintain compatibility with 3AB/3AG holders and deliver equivalent AC circuit protection at the specified 1 A, 250 V rating.

Parameter Comparison

Parameter	BK/MDA-1	BK/MDA-1-R	MDA-1-R	0326001.HXP	0326001.MXP	0326001.VXP	0001.2524
Manufacturer	Eaton	Eaton	Eaton	Littelfuse	Littelfuse	Littelfuse	SCHURTER
Current Rating (A)	1	1	1	1	1	1	1
Voltage Rating AC (V)	250	250	250	250	250	250	250
Voltage Rating DC (V)	—	—	—	125	125	125	63
Fuse Type	Cartridge, Ceramic	Cartridge, Ceramic	Cartridge, Ceramic	Cartridge, Ceramic	Cartridge, Ceramic	Cartridge, Ceramic	Cartridge, Glass
Response Time	Slow Blow	Slow Blow	Slow Blow	Slow Blow	Slow Blow	Slow Blow	Slow Blow
Package / Case	3AB, 3AG, 1/4" x 1-1/4"	3AB, 3AG, 1/4" x 1-1/4"	3AB, 3AG, 1/4" x 1-1/4"	3AB, 3AG, 1/4" x 1-1/4"	3AB, 3AG, 1/4" x 1-1/4"	3AB, 3AG, 1/4" x 1-1/4"	3AB, 3AG, 1/4" x 1-1/4"
Size / Dimension	0.250" Dia x 1.250" L (6.35mm x 31.75mm)	0.250" Dia x 1.250" L (6.35mm x 31.75mm)	0.250" Dia x 1.250" L (6.35mm x 31.75mm)	0.250" Dia x 1.250" L (6.35mm x 31.75mm)	0.250" Dia x 1.250" L (6.35mm x 31.75mm)	0.250" Dia x 1.250" L (6.35mm x 31.75mm)	0.250" Dia x 1.252" L (6.35mm x 31.80mm)
Breaking Capacity @ Rated Voltage	35 A	35 A	35 A	100 A AC, 10 kA DC	100 A AC, 10 kA DC	100 A AC, 10 kA DC	1.5 kA AC, 20 kA DC
Melting I²t	11.1	0.9	0.9	16.3	16.3	16.3	2.4
DC Cold Resistance (Ohms)	0.56	0.38	0.38	0.389	0.389	0.389	—
Product Status	Obsolete	Active	Active	Active	Active	Active	Obsolete
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Approval Agency	CSA, UL	CE, CSA, UL	CE, CSA, UL	CE, CSA, PSE, UL	CE, CSA, PSE, UL	CE, CSA, PSE, UL	cURus

Engineering Selection Recommendations

Primary Recommendation: Eaton Direct Replacements

Parts BK/MDA-1-R and MDA-1-R are the preferred substitutes for the obsolete BK/MDA-1. Both parts are manufactured by Eaton Electronics Division and maintain identical electrical and mechanical specifications. These replacements offer:

Active product status with ongoing manufacturing support
ROHS3 compliance and CE certification (in addition to CSA and UL)
Improved DC cold resistance (0.38 Ohms vs. 0.56 Ohms)
Reduced melting I²t (0.9 vs. 11.1)
Bulk packaging availability

Secondary Recommendation: Littelfuse Series 326 Alternatives

Parts 0326001.HXP, 0326001.MXP, and 0326001.VXP (Littelfuse Inc.) provide cross-manufacturer equivalence with enhanced specifications:

Active product status with extended operating temperature range (-55°C to 125°C)
Higher breaking capacity (100 A AC, 10 kA DC vs. 35 A)
Expanded DC voltage rating (125 V DC)
Comprehensive approval certifications (CE, CSA, PSE, UL)
ROHS3 compliance and REACH unaffected status

Tertiary Option: SCHURTER Glass Fuse Alternative

Part 0001.2524 (SCHURTER Inc., Series SPT 6.3x32) offers functional equivalence with glass fuse construction:

Identical AC voltage and current ratings (250 V, 1 A)
Extended operating temperature range (-40°C to 85°C)
Higher DC breaking capacity (20 kA DC)
cURus certification
Obsolete product status limits long-term availability

Frequently Asked Questions (FAQ)

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

A: Yes. Both parts are direct Eaton replacements with identical current rating (1 A), AC voltage rating (250 V), fuse type (ceramic cartridge), package designation (3AB, 3AG), and physical dimensions (0.250" Dia x 1.250" L). They install in the same 3AB/3AG fuse holders without modification.

Q: What is the difference between ceramic and glass fuse cartridges in this application?

A: The BK/MDA-1 uses ceramic construction, as do the Littelfuse Series 326 alternatives (0326001.HXP, 0326001.MXP, 0326001.VXP). The SCHURTER 0001.2524 uses glass construction. Both materials provide equivalent AC circuit protection at 1 A, 250 V. Ceramic fuses typically offer higher breaking capacity and wider temperature ranges, while glass fuses provide visual indication of element status. All are compatible with 3AB/3AG holders.

Q: Are the Littelfuse 0326001 series parts suitable for DC applications?

A: The Littelfuse parts (0326001.HXP, 0326001.MXP, 0326001.VXP) are rated for 125 V DC, providing expanded DC capability beyond the original BK/MDA-1 specification. The SCHURTER 0001.2524 is rated for 63 V DC. Selection depends on the specific DC voltage requirements of the application.

Q: What does the melting I²t value indicate?

A: Melting I²t is a thermal characteristic that describes the fuse element's response to overcurrent. Lower values indicate faster thermal response. The Eaton replacements (BK/MDA-1-R, MDA-1-R) have reduced melting I²t (0.9) compared to the original BK/MDA-1 (11.1), indicating improved response characteristics. The Littelfuse parts have higher melting I²t (16.3), indicating slower thermal response suitable for applications with higher inrush currents.

Q: Are all substitute parts RoHS compliant?

A: The original BK/MDA-1 is RoHS non-compliant. All substitute parts listed (BK/MDA-1-R, MDA-1-R, 0326001.HXP, 0326001.MXP, 0326001.VXP, and 0001.2524) are ROHS3 compliant, meeting current environmental regulations.

Q: Which substitute part offers the highest breaking capacity?

A: The Littelfuse Series 326 parts (0326001.HXP, 0326001.MXP, 0326001.VXP) offer the highest breaking capacity at 100 A AC and 10 kA DC, compared to 35 A for the Eaton parts and 1.5 kA AC / 20 kA DC for the SCHURTER part.

Q: Can I use these fuses in applications requiring DC protection?

A: The original BK/MDA-1 does not specify a DC voltage rating. For DC applications, the Littelfuse alternatives (125 V DC rating) or SCHURTER alternative (63 V DC rating) are appropriate selections. Verify the application's DC voltage requirement against the substitute part's DC rating before installation.

Q: What certifications should I verify for regulatory compliance?

A: The original BK/MDA-1 carries CSA and UL certifications. The Eaton replacements (BK/MDA-1-R, MDA-1-R) add CE certification. The Littelfuse parts include CE, CSA, PSE, and UL certifications. The SCHURTER part carries cURus certification. Select the substitute part whose certification portfolio matches your application's regulatory requirements.

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