Littelfuse 0326.400MXP Equivalent & Substitute Parts

Part Overview

The Littelfuse 0326.400MXP is a 400 mA ceramic cartridge fuse rated for 250 V AC and 125 V DC operation. This slow-blow fuse is designed for applications requiring circuit protection in industrial and commercial equipment. The part is actively manufactured and widely stocked, with 726 units available in inventory. Substitute parts may be required due to supply chain constraints, regional availability, or specific application requirements where alternative electrical characteristics are acceptable within design parameters.

Substiute Parts

0326.400MXP

Littelfuse Inc.In Stock: 7410326.400MXP Datasheet

Current PartRFQ

BK/MDA-4/10-R

Eaton - Electronics DivisionIn Stock: 736BK/MDA-4/10-R Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

The Eaton BK/MDA-4/10-R qualifies as a direct substitute based on the following critical parameters:

• Current Rating: Both parts are rated at 400 mA
• Voltage Rating - AC: Both parts are rated at 250 V AC
• Fuse Type: Both are ceramic cartridge fuses
• Response Time: Both are slow-blow fuses
• Package / Case: Both use 3AB, 3AG, 1/4" x 1-1/4" form factor
• Physical Dimensions: Identical at 0.250" Dia x 1.250" L (6.35mm x 31.75mm)
• Regulatory Compliance: Both hold CE, CSA, and UL approvals
• RoHS Compliance: Both are ROHS3 compliant

The substitute part differs in DC voltage rating specification and melting I²t characteristics, which must be evaluated against specific application requirements.

Parameter Comparison

Engineering Selection Recommendations

Both the Littelfuse 0326.400MXP and Eaton BK/MDA-4/10-R are active products with identical regulatory certifications (CE, CSA, UL) and equivalent RoHS3 compliance status. Selection between these parts should be based on application-specific requirements:

• AC-only applications: The Eaton BK/MDA-4/10-R is suitable where DC voltage rating is not a design requirement
• AC/DC dual-voltage applications: The Littelfuse 0326.400MXP with its specified 125 V DC rating is the appropriate choice
• Thermal response characteristics: The lower melting I²t value (0.64) of the Eaton part indicates faster thermal response compared to the Littelfuse part (1.33)
• Electrical resistance: The higher DC cold resistance of the Eaton part (4 Ohms vs. 1.935 Ohms) may impact circuit behavior in low-voltage DC applications

Both parts are mechanically and electrically compatible within their specified ratings and holder requirements (3AB, 3AG).

Frequently Asked Questions (FAQ)

Q: Can the Eaton BK/MDA-4/10-R be used in place of the Littelfuse 0326.400MXP in all applications?

A: The Eaton part is compatible for AC applications at 250 V and 400 mA. For applications requiring DC voltage operation at 125 V, the Littelfuse part with its specified DC rating is the correct choice. Verify your circuit design voltage requirements before substitution.

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

A: The melting I²t value indicates the thermal energy required to melt the fuse element. The Eaton part (0.64) will respond faster to thermal stress than the Littelfuse part (1.33). This difference may affect nuisance trip behavior in circuits with high inrush currents.

Q: Are both parts physically interchangeable?

A: Yes. Both parts have identical physical dimensions (0.250" Dia x 1.250" L) and use the same 3AB, 3AG holder form factor. Physical installation is identical.

Q: Do both parts meet the same regulatory standards?

A: Yes. Both parts hold CE, CSA, and UL approvals and are ROHS3 compliant, meeting equivalent regulatory requirements for industrial and commercial applications.

Q: What is the difference in DC cold resistance between these parts?

A: The Littelfuse part has 1.935 Ohms while the Eaton part has 4 Ohms. In low-voltage DC circuits, this resistance difference may affect voltage drop and circuit behavior. Evaluate your specific circuit requirements.