BK/MDL-20 Equivalent & Substitute Parts

Part Overview

The BK/MDL-20 is a 20 A, 32 V AC/DC slow-blow glass cartridge fuse manufactured by Eaton - Electronics Division. This fuse is designed for use in 3AB and 3AG fuse holders with dimensions of 1/4" x 1-1/4" (6.35mm x 31.75mm). The part carries obsolete product status, making identification of equivalent and substitute components necessary for ongoing system maintenance and component replacement.

Key Parameters

Parameter	Value
Current Rating	20 A
Voltage Rating - AC	32 V
Fuse Type	Cartridge, Glass
Response Time	Slow Blow
Package / Case	3AB, 3AG, 1/4" x 1-1/4"
Breaking Capacity @ Rated Voltage	1 kA
Size / Dimension	0.250" Dia x 1.250" L (6.35mm x 31.75mm)
Mounting Type	Requires Holder
Approval Agency	CSA, UL

Substitute Part Grouping Explanation

Substitution of the BK/MDL-20 is determined by strict equivalence across the following critical parameters:

Primary Substitution Criteria:

Current Rating: 20 A
Voltage Rating - AC: 32 V
Fuse Type: Cartridge, Glass
Response Time: Slow Blow
Package / Case: 3AB, 3AG, 1/4" x 1-1/4"
Physical Dimensions: 0.250" Dia x 1.250" L

Substitute parts are grouped into two categories:

Direct Manufacturer Equivalents (Eaton - Electronics Division): Parts BK/MDL-20-R, MDL-20, and MDL-20-R maintain identical electrical and mechanical specifications to the main part. These components are sourced from the original manufacturer and provide direct functional replacement.

Cross-Manufacturer Parametric Equivalents (Littelfuse Inc.): Parts 0313020.HXP, 0313020.MXP, and 0313020.VXP meet all critical electrical and mechanical parameters. These components are manufactured by Littelfuse Inc. and are functionally equivalent within the specified parameter set.

Non-Equivalent Part (SCHURTER Inc.): Part 0034.3430 differs in voltage rating (250 V AC versus 32 V AC) and breaking capacity (200 A versus 1 kA). This part is listed as a similar component but does not meet substitution criteria for the BK/MDL-20.

Parameter Comparison

Part Number	Manufacturer	Current Rating (A)	Voltage Rating - AC (V)	Response Time	Breaking Capacity @ Rated Voltage	Product Status	RoHS Status	Approval Agency
BK/MDL-20	Eaton - Electronics Division	20	32	Slow Blow	1 kA	Obsolete	RoHS non-compliant	CSA, UL
BK/MDL-20-R	Eaton - Electronics Division	20	32	Slow Blow	1 kA	Active	ROHS3 Compliant	CE, CSA, UL
MDL-20	Eaton - Electronics Division	20	32	Slow Blow	1 kA	Active	Not specified	CE
MDL-20-R	Eaton - Electronics Division	20	32	Slow Blow	1 kA	Active	RoHS Compliant	CE, CSA, UL
0313020.HXP	Littelfuse Inc.	20	32	Slow Blow	300 A	Active	ROHS3 Compliant	UL
0313020.MXP	Littelfuse Inc.	20	32	Slow Blow	300 A	Active	ROHS3 Compliant	UL
0313020.VXP	Littelfuse Inc.	20	32	Slow Blow	300 A	Active	ROHS3 Compliant	UL
0034.3430	SCHURTER Inc.	20	250	Slow Blow	200 A	Obsolete	ROHS3 Compliant	CE

Engineering Selection Recommendations

Eaton - Electronics Division Direct Replacements:

BK/MDL-20-R, MDL-20, and MDL-20-R are direct manufacturer equivalents sourced from Eaton - Electronics Division. All three parts maintain identical electrical and mechanical specifications to the obsolete BK/MDL-20. BK/MDL-20-R and MDL-20-R carry active product status with enhanced compliance certifications (ROHS3 Compliant, CE/CSA/UL approval). MDL-20 carries active status with CE approval. These components are recommended for applications requiring original manufacturer sourcing and full specification equivalence.

Littelfuse Inc. Cross-Manufacturer Equivalents:

Parts 0313020.HXP, 0313020.MXP, and 0313020.VXP are manufactured by Littelfuse Inc. and meet all critical electrical and mechanical parameters of the BK/MDL-20. All three Littelfuse components carry active product status, ROHS3 compliance, and UL approval. These parts feature higher breaking capacity (300 A versus 1 kA) and higher melting I²t values (9560 versus 2914), indicating enhanced performance characteristics within the same electrical rating envelope. These components are suitable for applications where cross-manufacturer sourcing is acceptable and enhanced performance margins are beneficial.

Non-Equivalent Component:

Part 0034.3430 from SCHURTER Inc. operates at 250 V AC, which exceeds the 32 V AC rating of the BK/MDL-20. This part is not suitable as a substitute for the BK/MDL-20 and should not be selected for direct replacement applications.

Frequently Asked Questions (FAQ)

Q: Can BK/MDL-20-R be used as a direct replacement for the obsolete BK/MDL-20?

A: Yes. BK/MDL-20-R is a direct manufacturer equivalent from Eaton - Electronics Division with identical electrical and mechanical specifications. The part carries active product status and enhanced compliance certifications (ROHS3 Compliant, CE/CSA/UL approval).

Q: What is the difference between BK/MDL-20-R, MDL-20, and MDL-20-R?

A: All three parts are Eaton - Electronics Division equivalents with identical 20 A, 32 V AC/DC ratings and slow-blow response. BK/MDL-20-R and MDL-20-R carry ROHS3 compliance and CE/CSA/UL approval. MDL-20 carries CE approval only. All three maintain the same 3AB/3AG package and 1/4" x 1-1/4" dimensions.

Q: Can Littelfuse parts 0313020.HXP, 0313020.MXP, or 0313020.VXP replace the BK/MDL-20?

A: Yes. These Littelfuse components meet all critical electrical and mechanical parameters: 20 A current rating, 32 V AC voltage rating, slow-blow response, and 3AB/3AG package with 1/4" x 1-1/4" dimensions. All three carry active product status and ROHS3 compliance. Breaking capacity differs (300 A versus 1 kA), but this represents enhanced performance within the same electrical rating envelope.

Q: Why does part 0034.3430 appear in the substitute list if it cannot replace the BK/MDL-20?

A: Part 0034.3430 is listed as a similar component due to matching current rating (20 A) and physical dimensions (1/4" x 1-1/4"). However, the voltage rating (250 V AC) differs significantly from the BK/MDL-20 (32 V AC), making it unsuitable for direct substitution. This part is included for reference only.

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

A: Yes. All equivalent and substitute parts listed maintain the 3AB, 3AG package designation and 1/4" x 1-1/4" physical dimensions, ensuring mechanical compatibility with standard fuse holders designed for the BK/MDL-20.

Q: What compliance certifications should I prioritize when selecting a substitute?

A: The original BK/MDL-20 carries CSA and UL approval. For applications requiring maintained certification levels, BK/MDL-20-R and MDL-20-R provide CSA and UL approval. Littelfuse parts 0313020.HXP, 0313020.MXP, and 0313020.VXP carry UL approval. MDL-20 carries CE approval. Selection should align with system certification requirements.

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