Littelfuse 0326.400H Ceramic Fuse - Equivalent & Substitute Parts

Part Overview

The Littelfuse 0326.400H is a 400 mA, 250 V AC ceramic cartridge fuse with slow-blow response characteristics, designed for 3AB and 3AG holder applications. This part is classified as obsolete, necessitating identification of active equivalent alternatives that maintain electrical and mechanical compatibility. Substitute parts must match the current rating, voltage rating, package dimensions, and holder requirements to ensure direct replacement capability in existing designs.

Substiute Parts

0326.400H

Littelfuse Inc.In Stock: 9100326.400H Datasheet

Current PartRFQ

0326.400HXP

Littelfuse Inc.In Stock: 9260326.400HXP Datasheet

DirectRFQ

0326.400MXP

Littelfuse Inc.In Stock: 7410326.400MXP Datasheet

Parametric EquivalentRFQ

0326.400VXP

Littelfuse Inc.In Stock: 7750326.400VXP Datasheet

Parametric EquivalentRFQ

BK/MDA-4/10-R

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

Parametric EquivalentRFQ

MDA-4/10-R

Eaton - Electronics DivisionIn Stock: 1098MDA-4/10-R Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict equivalence across the following parameters: current rating (400 mA), AC voltage rating (250 V), fuse type (ceramic cartridge), response time (slow blow), and physical package dimensions (3AB, 3AG, 1/4" x 1-1/4"). Parts meeting these criteria are classified as direct or parametric equivalents.

Direct Manufacturer Equivalent (Littelfuse):

• 0326.400HXP: Active status, adds 125 V DC rating, enhanced certifications (CE, CSA, UL), RoHS3 compliant, operating temperature -55°C to 125°C

Parametric Equivalents (Littelfuse):

• 0326.400MXP: Active status, identical electrical and mechanical specifications to 0326.400HXP
• 0326.400VXP: Active status, identical electrical and mechanical specifications to 0326.400HXP

Parametric Equivalents (Eaton - Electronics Division):

• BK/MDA-4/10-R: Active status, MDA series, black color, alternative manufacturer option
• MDA-4/10-R: Active status, MDA series, black color, alternative manufacturer option

Parameter Comparison

Engineering Selection Recommendations

For applications requiring direct replacement of the obsolete 0326.400H, the Littelfuse 0326.400HXP, 0326.400MXP, or 0326.400VXP are preferred selections. These parts maintain identical electrical characteristics (400 mA, 250 V AC, slow-blow response) and mechanical compatibility (3AB/3AG package, 1/4" x 1-1/4" dimensions) while offering active product status, enhanced regulatory compliance (CE certification addition), and RoHS3 compliance. The addition of 125 V DC rating in these alternatives provides expanded application flexibility without compromising AC circuit performance.

The Eaton MDA series alternatives (BK/MDA-4/10-R and MDA-4/10-R) provide functionally equivalent substitution with identical current rating, voltage rating, package, and response time characteristics. Selection between Littelfuse and Eaton alternatives depends on supply chain requirements and existing design qualification. Note that Eaton MDA series parts exhibit lower melting I²t (0.64 versus 1.33) and higher DC cold resistance (4 Ohms versus 1.935 Ohms), which may affect circuit behavior in specific applications.

Frequently Asked Questions (FAQ)

Q: Can the 0326.400HXP directly replace the 0326.400H in existing designs?

A: Yes. The 0326.400HXP maintains identical current rating (400 mA), AC voltage rating (250 V), fuse type (ceramic cartridge), response time (slow blow), and physical dimensions (3AB/3AG, 1/4" x 1-1/4"). The addition of 125 V DC rating does not affect AC circuit operation. Both parts require the same 3AB or 3AG holder.

Q: What is the difference between the Littelfuse 0326.400HXP, 0326.400MXP, and 0326.400VXP?

A: These three parts are parametric equivalents with identical electrical and mechanical specifications. Differences exist only in packaging designation or internal manufacturing variants. All three are suitable for direct substitution of the 0326.400H.

Q: How do the Eaton MDA series fuses compare to the Littelfuse 326 series?

A: Both series meet the core substitution criteria: 400 mA current rating, 250 V AC voltage rating, ceramic cartridge type, slow-blow response, and 3AB/3AG package compatibility. The primary differences are melting I²t (Eaton 0.64 versus Littelfuse 1.33) and DC cold resistance (Eaton 4 Ohms versus Littelfuse 1.935 Ohms). These differences may impact circuit protection characteristics in specific applications.

Q: Are all substitute parts RoHS compliant?

A: Yes. All active substitute parts listed (0326.400HXP, 0326.400MXP, 0326.400VXP, BK/MDA-4/10-R, MDA-4/10-R) are RoHS3 compliant. The original 0326.400H is RoHS non-compliant.

Q: What certifications do the substitute parts carry?

A: The Littelfuse alternatives (0326.400HXP, 0326.400MXP, 0326.400VXP) carry CE, CSA, and UL certifications. The Eaton alternatives (BK/MDA-4/10-R, MDA-4/10-R) also carry CE, CSA, and UL certifications. All meet international safety standards for ceramic cartridge fuses.

Q: Can I use these fuses in both AC and DC circuits?

A: The Littelfuse 0326.400HXP, 0326.400MXP, and 0326.400VXP are rated for both 250 V AC and 125 V DC operation. The Eaton MDA series parts are rated for 250 V AC; DC rating is not specified. Verify DC application requirements against the specific part's voltage rating.