Equivalent & Substitute Parts for BK/MDL-6-1/4

Part Overview

The BK/MDL-6-1/4 is a 6.25 A, 250 V AC/DC glass cartridge fuse manufactured by Eaton - Electronics Division. This component is classified as obsolete, requiring identification of active equivalent and substitute parts for continued system support and procurement. The fuse operates with slow-blow response characteristics and requires a 3AB or 3AG holder for installation. Due to its obsolete status, direct replacement with active product variants is necessary for new designs and maintenance applications.

Key Parameters

Parameter	Value
Current Rating	6.25 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)
Breaking Capacity @ Rated Voltage	200 A
Mounting Type	Requires Holder

Substitute Part Grouping Explanation

Substitution eligibility for the BK/MDL-6-1/4 is determined by strict equivalence across the following parameters:

Critical Matching Parameters:

Current Rating: 6.25 A (exact match required)
Voltage Rating (AC): 250 V (exact match required)
Fuse Type: Cartridge, Glass (exact match required)
Response Time: Slow Blow (exact match required)
Package / Case: 3AB, 3AG, 1/4" x 1-1/4" (exact match required)
Size / Dimension: 0.250" Dia x 1.250" L (exact match required)
Breaking Capacity @ Rated Voltage: 200 A (exact match required)

All substitute parts listed below meet these critical parameters. Variations in secondary parameters such as DC Cold Resistance, Melting I²t, RoHS compliance status, and approval agencies do not affect functional substitutability within the specified electrical and mechanical constraints.

Parameter Comparison

Part Number	Manufacturer	Current Rating (A)	Voltage (V AC)	Response Time	Package	Breaking Capacity (A)	Product Status	RoHS Status	DC Cold Resistance (Ohms)
BK/MDL-6-1/4	Eaton - Electronics Division	6.25	250	Slow Blow	3AB, 3AG, 1/4" x 1-1/4"	200	Obsolete	RoHS non-compliant	0.018
BK/MDL-6-1/4-R	Eaton - Electronics Division	6.25	250	Slow Blow	3AB, 3AG, 1/4" x 1-1/4"	200	Active	ROHS3 Compliant	0.02
MDL-6-1/4-R	Eaton - Electronics Division	6.25	250	Slow Blow	3AB, 3AG, 1/4" x 1-1/4"	200	Active	RoHS Compliant	0.02
BK/MDQ-6-1/4	Eaton - Electronics Division	6.25	250	Slow Blow	3AB, 3AG, 1/4" x 1-1/4"	200	Active	RoHS non-compliant	0.0169
03136.25HXIDP	Littelfuse Inc.	6.25	250	Slow Blow	3AB, 3AG, 1/4" x 1-1/4"	200	Active	ROHS3 Compliant	0.0154
03136.25HXP	Littelfuse Inc.	6.25	250	Slow Blow	3AB, 3AG, 1/4" x 1-1/4"	200	Active	ROHS3 Compliant	0.0154
03136.25MXP	Littelfuse Inc.	6.25	250	Slow Blow	3AB, 3AG, 1/4" x 1-1/4"	200	Active	ROHS3 Compliant	0.0154
03136.25VXIDP	Littelfuse Inc.	6.25	250	Slow Blow	3AB, 3AG, 1/4" x 1-1/4"	200	Active	ROHS3 Compliant	0.0154
03136.25VXP	Littelfuse Inc.	6.25	250	Slow Blow	3AB, 3AG, 1/4" x 1-1/4"	200	Active	ROHS3 Compliant	0.0154

Engineering Selection Recommendations

Primary Recommendation: BK/MDL-6-1/4-R or MDL-6-1/4-R

The BK/MDL-6-1/4-R and MDL-6-1/4-R are direct Eaton equivalents with active product status. Both maintain identical electrical and mechanical specifications to the obsolete BK/MDL-6-1/4. The BK/MDL-6-1/4-R carries ROHS3 compliance certification, while MDL-6-1/4-R carries RoHS compliance. Both are approved by CE, CSA, and UL agencies. These parts are preferred for applications requiring continuity with the original Eaton product line.

Secondary Recommendation: Littelfuse 313 Series (03136.25HXIDP, 03136.25HXP, 03136.25MXP, 03136.25VXIDP, 03136.25VXP)

The Littelfuse 313 series cartridge fuses meet all critical electrical and mechanical parameters. All variants carry ROHS3 compliance and extended approval certifications including CE, CSA, K-MARK, PSE, and UL. Operating temperature range extends to -55°C ~ 125°C. These parts are suitable for applications where multi-source qualification is required or where Littelfuse supply chain preference exists.

Alternative Recommendation: BK/MDQ-6-1/4

The BK/MDQ-6-1/4 is an active Eaton product from the MDQ series meeting all critical parameters. This part carries CSA and UL approvals. Selection of this variant is appropriate where MDQ series standardization is established within the design or procurement framework.

Frequently Asked Questions (FAQ)

Q: Can BK/MDL-6-1/4-R be used as a direct replacement for BK/MDL-6-1/4?

A: Yes. Both parts share identical current rating (6.25 A), voltage rating (250 V AC), fuse type (cartridge, glass), response time (slow blow), package designation (3AB, 3AG), physical dimensions (0.250" Dia x 1.250" L), and breaking capacity (200 A). The primary difference is product status: BK/MDL-6-1/4-R is active while BK/MDL-6-1/4 is obsolete.

Q: What is the difference between Eaton MDL and MDQ series fuses?

A: Both series meet the specified 6.25 A, 250 V AC, slow-blow cartridge fuse parameters. The MDQ series (BK/MDQ-6-1/4) represents an alternative Eaton product line. Selection between MDL and MDQ variants depends on design standardization and supply chain requirements, as both are electrically and mechanically equivalent.

Q: Are Littelfuse 313 series fuses compatible with Eaton fuse holders?

A: Yes. All Littelfuse 313 series parts listed (03136.25HXIDP, 03136.25HXP, 03136.25MXP, 03136.25VXIDP, 03136.25VXP) share the identical 3AB, 3AG package designation and 0.250" Dia x 1.250" L physical dimensions as the Eaton BK/MDL-6-1/4. They are mechanically compatible with standard 3AB and 3AG fuse holders.

Q: What does the suffix "-R" indicate on Eaton part numbers?

A: The "-R" suffix on BK/MDL-6-1/4-R and MDL-6-1/4-R indicates these are active replacement variants of the obsolete BK/MDL-6-1/4. Both "-R" variants maintain full electrical and mechanical equivalence while offering updated compliance certifications and active product status.

Q: Which substitute part has the lowest DC cold resistance?

A: The Littelfuse 313 series parts (03136.25HXIDP, 03136.25HXP, 03136.25MXP, 03136.25VXIDP, 03136.25VXP) all exhibit 0.0154 Ohms DC cold resistance, which is lower than the original BK/MDL-6-1/4 (0.018 Ohms) and the Eaton active variants (0.02 Ohms for BK/MDL-6-1/4-R and MDL-6-1/4-R, 0.0169 Ohms for BK/MDQ-6-1/4).

Q: Are all substitute parts RoHS compliant?

A: No. The Eaton BK/MDQ-6-1/4 and the original BK/MDL-6-1/4 are RoHS non-compliant. The Eaton BK/MDL-6-1/4-R is ROHS3 compliant, MDL-6-1/4-R is RoHS compliant, and all Littelfuse 313 series variants are ROHS3 compliant. RoHS compliance requirements should be verified against your application specifications.

Q: What approval agencies certify these fuse products?

A: The original BK/MDL-6-1/4 carries CSA and UL approvals. Active Eaton variants (BK/MDL-6-1/4-R, MDL-6-1/4-R) add CE certification. The BK/MDQ-6-1/4 carries CSA and UL approvals. All Littelfuse 313 series variants carry CE, CSA, K-MARK, PSE, and UL certifications, providing the broadest international approval coverage.

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