Equivalent & Substitute Parts for MDQ-1-1/4 Glass Cartridge Fuse

Part Overview

The MDQ-1-1/4 is a 1.25 A, 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 is currently active in production with 830 pieces in stock.

Equivalent substitute parts are necessary when the primary MDQ-1-1/4 becomes unavailable, when design requirements mandate alternative certifications, or when supply chain optimization requires sourcing from multiple manufacturers. Substitute parts must maintain identical electrical ratings, mechanical dimensions, and functional characteristics to ensure direct interchangeability without circuit redesign.

Substiute Parts

MDQ-1-1/4

Eaton - Electronics DivisionIn Stock: 929MDQ-1-1/4 Datasheet

Current PartRFQ

BK/MDL-1-1/4-R

Eaton - Electronics DivisionIn Stock: 4197BK/MDL-1-1/4-R Datasheet

Parametric EquivalentRFQ

MDL-1-1/4-R

Eaton - Electronics DivisionIn Stock: 1149MDL-1-1/4-R Datasheet

Parametric EquivalentRFQ

0034.3418

SCHURTER Inc.In Stock: 10150034.3418 Datasheet

Parametric EquivalentRFQ

0034.5227

SCHURTER Inc.In Stock: 8860034.5227 Datasheet

Parametric EquivalentRFQ

03131.25HXP

Littelfuse Inc.In Stock: 110603131.25HXP Datasheet

Parametric EquivalentRFQ

03131.25MXP

Littelfuse Inc.In Stock: 223103131.25MXP Datasheet

Parametric EquivalentRFQ

03131.25VXP

Littelfuse Inc.In Stock: 73403131.25VXP Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

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

Primary Equivalence Criteria:

• Current Rating: 1.25 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 (6.35mm x 31.75mm) (exact match required)

All substitute parts listed below meet these primary equivalence criteria and are therefore direct functional replacements. Secondary parameters such as breaking capacity, melting I²t, DC cold resistance, and approval agencies may vary between manufacturers but do not affect interchangeability within the specified electrical and mechanical constraints.

Parameter Comparison

Engineering Selection Recommendations

Active Product Substitutes (Recommended for New Designs):

The MDL-1-1/4-R, BK/MDL-1-1/4-R, 03131.25HXP, 03131.25MXP, and 03131.25VXP are all active products with current manufacturing status. These parts are suitable for new circuit designs and long-term production applications.

• Eaton MDL-1-1/4-R and BK/MDL-1-1/4-R: Both are manufactured by Eaton - Electronics Division and provide higher breaking capacity (100A) compared to the MDQ-1-1/4 (35A). The BK/MDL-1-1/4-R variant has the highest inventory availability (4187 pieces). Both hold CE, CSA, and UL certifications.

• Littelfuse 03131.25HXP, 03131.25MXP, 03131.25VXP: All three Littelfuse variants are from the 313 series and provide 100A breaking capacity. These parts hold CE, CSA, PSE, and UL certifications. The 03131.25MXP has the highest inventory (2184 pieces) among the Littelfuse options.

Obsolete Product Substitutes (Legacy Applications Only):

The SCHURTER parts 0034.3418 and 0034.5227 are marked as obsolete and should only be used for replacement in existing equipment where original part specifications must be maintained. The 0034.3418 matches the 35A breaking capacity of the MDQ-1-1/4, while the 0034.5227 provides 100A breaking capacity.

Certification Considerations:

All active substitute parts hold UL and CSA certifications, ensuring compliance with North American standards. The Littelfuse variants additionally hold PSE certification for Japanese market applications. The MDQ-1-1/4 holds CSA and UL certifications. Selection should account for the specific regulatory requirements of the target application.

Frequently Asked Questions (FAQ)

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

A: Yes. Both parts share identical electrical ratings (1.25 A, 250 V AC), fuse type (cartridge, glass), response time (slow blow), and mechanical dimensions (0.250" Dia x 1.250" L). The MDL-1-1/4-R provides higher breaking capacity (100A versus 35A), which does not affect interchangeability. Both require the same 3AB or 3AG holder.

Q: What is the difference between the Littelfuse 03131.25HXP, 03131.25MXP, and 03131.25VXP variants?

A: All three Littelfuse parts are electrically and mechanically identical. They share the same current rating (1.25 A), voltage rating (250 V), dimensions (0.250" Dia x 1.250" L), and breaking capacity (100A). The designations HXP, MXP, and VXP represent different product variants within the 313 series but do not affect functional equivalence. Selection between these variants should be based on inventory availability and supply chain requirements.

Q: Are the SCHURTER parts 0034.3418 and 0034.5227 suitable for new designs?

A: No. Both SCHURTER parts are marked as obsolete and should not be specified for new circuit designs. These parts are available only for replacement in legacy equipment where original specifications must be maintained. For new applications, select from the active product substitutes: Eaton MDL-1-1/4-R, BK/MDL-1-1/4-R, or Littelfuse 03131.25HXP, 03131.25MXP, or 03131.25VXP.

Q: Does the higher breaking capacity of MDL-1-1/4-R (100A) affect circuit performance compared to MDQ-1-1/4 (35A)?

A: No. Breaking capacity is the maximum current the fuse can safely interrupt without damage. It does not affect the fuse's response to normal circuit operation. Both the MDQ-1-1/4 and MDL-1-1/4-R will trip at 1.25 A with identical slow-blow response characteristics. The higher breaking capacity of the MDL-1-1/4-R provides additional safety margin in high-fault-current applications.

Q: What holder types are compatible with these fuses?

A: All listed substitute parts require 3AB or 3AG holders. The mechanical dimensions (0.250" Dia x 1.250" L) are identical across all parts, ensuring compatibility with any holder designed for these standard form factors.

Q: Which substitute part has the best inventory availability?

A: The BK/MDL-1-1/4-R has the highest inventory with 4187 pieces in stock, followed by 03131.25MXP with 2184 pieces. Both are active products suitable for immediate procurement.