Equivalent & Substitute Parts for MDL-3/4-R Glass Cartridge Fuse

Part Overview

The MDL-3/4-R is a 750 mA, 250 V AC/DC slow-blow glass cartridge fuse manufactured by Eaton - Electronics Division. This fuse is designed for use in 3AB and 3AG holders with dimensions of 1/4" x 1-1/4" (6.35mm x 31.75mm). The part maintains active product status with 1016 units in current inventory. Equivalent and substitute parts are identified based on matching electrical ratings, mechanical dimensions, response characteristics, and approval certifications to ensure direct functional interchangeability in circuit protection applications.

Substiute Parts

MDL-3/4-R

Eaton - Electronics DivisionIn Stock: 1041MDL-3/4-R Datasheet

Current PartRFQ

BK/MDL-3/4-R

Eaton - Electronics DivisionIn Stock: 1037BK/MDL-3/4-R Datasheet

DirectRFQ

0034.5223

SCHURTER Inc.In Stock: 8320034.5223 Datasheet

Parametric EquivalentRFQ

0313.750HXP

Littelfuse Inc.In Stock: 15090313.750HXP Datasheet

Parametric EquivalentRFQ

0313.750MXP

Littelfuse Inc.In Stock: 56670313.750MXP Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the MDL-3/4-R is determined by strict equivalence across the following critical parameters:

Electrical Parameters: Current rating of 750 mA, voltage rating of 250 V AC, and slow-blow response time must match exactly. Breaking capacity of 35A at rated voltage is required.

Mechanical Parameters: Package designation 3AB/3AG and physical dimensions of 0.250" diameter x 1.250" length (6.35mm x 31.75mm) must be identical to ensure compatibility with existing holder assemblies.

Functional Parameters: Fuse type must be cartridge glass construction. Mounting requirement of holder-based installation must be maintained.

Compliance Parameters: Approval certifications from CE, CSA, and/or UL are required. RoHS compliance status must be verified for regulatory adherence.

All identified substitute parts meet these criteria and are therefore functionally equivalent for direct replacement applications.

Parameter Comparison

Engineering Selection Recommendations

Primary Selection: BK/MDL-3/4-R (Eaton - Electronics Division) is the direct equivalent to MDL-3/4-R, manufactured by the same supplier with identical electrical and mechanical specifications. Both parts carry active product status and full CE, CSA, and UL certifications. This part is recommended for applications requiring exact specification matching.

Secondary Selection: 0313.750HXP and 0313.750MXP (Littelfuse Inc., Series 313) are parametric equivalents meeting all critical electrical and mechanical requirements. Both parts maintain active product status with CE, CSA, and UL approvals. The 0313.750MXP variant offers the highest inventory availability at 5623 units. These parts are suitable for direct replacement in circuit protection applications.

Alternative Selection: 0034.5223 (SCHURTER Inc., Series FST 6.3x32) meets all electrical and mechanical parameters with CSA and UL certifications. However, this part carries obsolete product status, indicating discontinued manufacturing. Selection of this part is not recommended for new designs or long-term supply chain requirements.

Compliance Consideration: All active-status substitute parts maintain RoHS3 compliance and REACH unaffected status, ensuring regulatory adherence in current manufacturing environments.

Frequently Asked Questions (FAQ)

Q: Can BK/MDL-3/4-R be used as a direct replacement for MDL-3/4-R?

A: Yes. BK/MDL-3/4-R is manufactured by Eaton - Electronics Division with identical current rating (750 mA), voltage rating (250 V AC), response time (slow blow), package designation (3AB, 3AG), and physical dimensions (0.250" Dia x 1.250" L). Both parts carry CE, CSA, and UL certifications and maintain active product status.

Q: Are Littelfuse 0313.750HXP and 0313.750MXP interchangeable with MDL-3/4-R?

A: Yes. Both Littelfuse parts meet the critical electrical parameters (750 mA, 250 V AC, slow blow, 35A breaking capacity) and mechanical requirements (3AB/3AG package, 0.250" Dia x 1.250" L dimensions). Both carry CE, CSA, and UL approvals and maintain active product status. Differences in melting I²t (7.16 versus 4.343) and DC cold resistance (0.6215 versus 0.397 Ohms) do not affect functional interchangeability within the specified electrical ratings.

Q: Why is 0034.5223 marked as obsolete?

A: The 0034.5223 (SCHURTER Inc.) carries obsolete product status, indicating that the manufacturer has discontinued production. While this part meets all electrical and mechanical specifications, its obsolete status creates supply chain risk and is not recommended for new applications or long-term inventory planning.

Q: What holder types are compatible with these fuses?

A: All listed fuses require 3AB or 3AG holder assemblies. The 1/4" x 1-1/4" (6.35mm x 31.75mm) physical dimensions ensure compatibility with standard holders designed for this package designation. Verify holder compatibility before installation.

Q: Are there differences in operating temperature ranges among the substitute parts?

A: The main part MDL-3/4-R does not specify an operating temperature range. Littelfuse parts (0313.750HXP and 0313.750MXP) specify -55°C to 125°C operation. SCHURTER part 0034.5223 also specifies -55°C to 125°C operation. For applications requiring specific temperature performance, consult the detailed datasheets of selected parts.

Q: What is the significance of different melting I²t values?

A: Melting I²t represents the thermal energy required to melt the fuse element. Variations among substitute parts (MDL-3/4-R: 4.343, Littelfuse: 7.16, SCHURTER: 9.04) reflect different fuse element designs. All parts maintain the same 750 mA current rating and 35A breaking capacity, ensuring equivalent circuit protection performance within specified electrical parameters.