MDL-1/8-R Equivalent & Substitute Parts Reference

Part Overview

The MDL-1/8-R is a 125 mA, 250 V AC/DC slow-blow glass cartridge fuse manufactured by Eaton - Electronics Division. This component 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 maintains Active product status and carries CE, CSA, and UL approvals. Substitute parts are necessary when primary inventory is unavailable, when sourcing from alternative manufacturers is required for supply chain optimization, or when design flexibility permits equivalent component selection within the same electrical and mechanical parameter set.

Substiute Parts

MDL-1/8-R

Eaton - Electronics DivisionIn Stock: 809MDL-1/8-R Datasheet

Current PartRFQ

BK/MDL-1/8-R

Eaton - Electronics DivisionIn Stock: 5146BK/MDL-1/8-R Datasheet

DirectRFQ

0034.5208

SCHURTER Inc.In Stock: 12940034.5208 Datasheet

DirectRFQ

0313.125HXP

Littelfuse Inc.In Stock: 11080313.125HXP Datasheet

Parametric EquivalentRFQ

0313.125MXP

Littelfuse Inc.In Stock: 18240313.125MXP Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the MDL-1/8-R is determined by strict equivalence across the following critical parameters:

Mandatory Matching Parameters:

• Current Rating: 125 mA
• Voltage Rating (AC): 250 V
• Response Time: Slow Blow
• Fuse Type: Cartridge, Glass
• Package / Case: 3AB, 3AG, 1/4" x 1-1/4"
• Breaking Capacity @ Rated Voltage: 35A
• Size / Dimension: 0.250" Dia x 1.250" L (6.35mm x 31.75mm)
• Mounting Type: Requires Holder

All identified substitute parts meet these mandatory parameters. Variations in secondary parameters such as DC Cold Resistance, Melting I²t, operating temperature range, and RoHS compliance status do not disqualify substitution eligibility when the primary electrical and mechanical specifications are identical.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute (Direct Equivalent): BK/MDL-1/8-R from Eaton - Electronics Division is the direct manufacturer equivalent to MDL-1/8-R. Both parts share identical electrical and mechanical specifications, identical approval certifications (CE, CSA, UL), and both maintain Active product status. This substitute offers the highest compatibility assurance with 5079 units in current inventory.

Secondary Substitutes (Parametric Equivalents): 0313.125HXP and 0313.125MXP from Littelfuse Inc. are parametric equivalents that satisfy all mandatory electrical and mechanical requirements. Both parts carry CE, CSA, and UL approvals matching the original specification. These components maintain Active product status and offer robust inventory availability (1030 and 1781 units respectively).

Tertiary Substitute (Obsolete Status): 0034.5208 from SCHURTER Inc. meets all mandatory electrical and mechanical parameters but carries Obsolete product status. This part holds CSA and UL approvals but lacks CE certification present in the primary part. Use of this substitute is limited to applications where obsolete component sourcing is acceptable and CE compliance is not required.

Frequently Asked Questions (FAQ)

Q: Can BK/MDL-1/8-R be used as a direct replacement for MDL-1/8-R? A: Yes. BK/MDL-1/8-R is manufactured by the same company (Eaton - Electronics Division) and shares identical electrical specifications (125 mA, 250 V AC/DC, Slow Blow), mechanical dimensions (0.250" Dia x 1.250" L), package type (3AB, 3AG), and approval certifications (CE, CSA, UL). Both parts are Active status products.

Q: What is the difference between the Littelfuse 0313.125HXP and 0313.125MXP? A: Both Littelfuse parts (0313.125HXP and 0313.125MXP) are parametric equivalents with identical electrical and mechanical specifications. The primary difference is inventory availability: 0313.125HXP has 1030 units in stock while 0313.125MXP has 1781 units. Both carry identical approvals and Active product status.

Q: Why is 0034.5208 marked as Obsolete? A: 0034.5208 from SCHURTER Inc. is classified as Obsolete product status. While it meets all mandatory electrical and mechanical parameters for substitution, its obsolete classification indicates limited future availability. This part also lacks CE certification, carrying only CSA and UL approvals.

Q: Are all substitute parts compatible with existing 3AB and 3AG fuse holders? A: Yes. All substitute parts share the identical package specification (3AB, 3AG, 1/4" x 1-1/4") and physical dimensions (0.250" Dia x 1.250" L / 6.35mm x 31.75mm). All parts require a fuse holder for mounting and are mechanically interchangeable.

Q: What approval certifications must a substitute part carry? A: The original MDL-1/8-R carries CE, CSA, and UL approvals. BK/MDL-1/8-R and both Littelfuse parts (0313.125HXP and 0313.125MXP) match this full certification set. SCHURTER 0034.5208 carries CSA and UL but lacks CE certification.

Q: Can I use these substitutes in applications requiring CE compliance? A: BK/MDL-1/8-R, 0313.125HXP, and 0313.125MXP all carry CE certification and are suitable for CE-compliant applications. SCHURTER 0034.5208 does not carry CE certification and is not suitable for applications requiring CE compliance.

Q: What is the significance of the different Melting I²t values? A: Melting I²t values vary among the substitute parts (MDL-1/8-R: 0.0422, SCHURTER 0034.5208: 0.288, Littelfuse parts: 0.152). These variations do not disqualify substitution when all other electrical and mechanical parameters match. The parts remain functionally equivalent within the specified 125 mA, 250 V, Slow Blow classification.

Q: Are there differences in operating temperature ranges? A: MDL-1/8-R does not specify an operating temperature range. SCHURTER 0034.5208 specifies -55°C ~ 125°C, and Littelfuse parts (0313.125HXP and 0313.125MXP) specify -55°C ~ 125°C. These temperature specifications do not affect substitution eligibility when the primary electrical and mechanical parameters are identical.