Equivalent & Substitute Parts for BK/MDQ-1/8

Part Overview

The Eaton BK/MDQ-1/8 is a 125 mA, 250 V AC/DC slow-blow glass fuse cartridge in 3AB/3AG package format (1/4" x 1-1/4"). This component requires a compatible fuse holder for installation and is classified as Active product status. 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

BK/MDQ-1/8

Eaton - Electronics DivisionIn Stock: 831BK/MDQ-1/8 Datasheet

Current PartRFQ

BK/MDL-1/8-R

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

Parametric EquivalentRFQ

0034.5208

SCHURTER Inc.In Stock: 12940034.5208 Datasheet

Parametric EquivalentRFQ

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 BK/MDQ-1/8 fuse cartridge is determined by the following criteria:

Primary Matching Parameters:

• Current Rating: 125 mA (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: 35A (exact match required)

All identified substitute parts meet these electrical and mechanical parameters, confirming direct interchangeability in applications requiring 125 mA, 250 V AC/DC slow-blow fuse protection with 3AB/3AG holder compatibility.

Parameter Comparison

Engineering Selection Recommendations

Primary Recommendation: BK/MDL-1/8-R

The BK/MDL-1/8-R from Eaton - Electronics Division is the preferred substitute. Both parts are manufactured by the same company, ensuring design consistency and manufacturing standards alignment. The BK/MDL-1/8-R carries Active product status and includes CE certification in addition to CSA and UL approvals. This part is ROHS3 compliant, addressing environmental regulatory requirements that the original BK/MDQ-1/8 does not meet.

Secondary Recommendations: 0313.125HXP and 0313.125MXP

Both Littelfuse 313 series parts (0313.125HXP and 0313.125MXP) are Active products with CE, CSA, and UL certifications. These parts are ROHS3 compliant and provide equivalent electrical and mechanical performance. Selection between these two Littelfuse variants depends on application-specific requirements not differentiated by the provided parameters.

Alternative: 0034.5208

The SCHURTER 0034.5208 meets all electrical and mechanical substitution criteria and carries CSA and UL approvals. However, this part is classified as Obsolete product status, making it unsuitable for new designs or long-term supply chain planning.

Frequently Asked Questions (FAQ)

Q: Can BK/MDQ-1/8 be directly replaced with BK/MDL-1/8-R?

A: Yes. Both parts share identical electrical ratings (125 mA, 250 V AC/DC), response characteristics (slow-blow), and mechanical dimensions (3AB/3AG, 1/4" x 1-1/4"). They are functionally interchangeable in any application requiring 3AB/3AG holder compatibility.

Q: What is the difference between 0313.125HXP and 0313.125MXP?

A: Both parts are Littelfuse 313 series fuses with identical electrical ratings, voltage ratings, response times, and mechanical dimensions. The provided parameters do not differentiate between these two variants. Selection should be based on application-specific requirements or supplier availability.

Q: Why is 0034.5208 listed if it is Obsolete?

A: The 0034.5208 meets all electrical and mechanical substitution criteria for the BK/MDQ-1/8. However, Obsolete product status indicates limited availability and unsuitability for new designs. This part is included for reference in legacy system maintenance only.

Q: Are all substitute parts ROHS3 compliant?

A: No. The original BK/MDQ-1/8 is RoHS non-compliant. All identified substitutes except 0034.5208 are ROHS3 compliant. The 0034.5208 is also ROHS3 compliant. If RoHS compliance is a design requirement, BK/MDL-1/8-R, 0313.125HXP, or 0313.125MXP are appropriate selections.

Q: Do all substitute parts require the same fuse holder?

A: Yes. All parts in this equivalency group use the 3AB/3AG package format with identical dimensions (0.250" Dia x 1.250" L). They are mechanically compatible with any holder designed for 3AB/3AG cartridge fuses.

Q: What approval certifications are required for my application?

A: The original BK/MDQ-1/8 carries CSA and UL certifications. Substitute parts BK/MDL-1/8-R, 0313.125HXP, and 0313.125MXP include CE certification in addition to CSA and UL. The 0034.5208 carries CSA and UL certifications only. Verify your application's regulatory requirements before final part selection.