Littelfuse 02321.25MXW Glass Cartridge Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 02321.25MXW is a 1.25 A, 250 V AC/DC glass cartridge fuse with a 5mm x 20mm form factor, designed for applications requiring medium-blow response characteristics. This part is classified as obsolete, necessitating identification of active equivalent and substitute components that maintain electrical and mechanical compatibility. Substitute parts must match the core electrical parameters (current rating, voltage rating, response time) and physical dimensions to ensure direct functional replacement in existing designs and assemblies.

Substiute Parts

02321.25MXW

Littelfuse Inc.In Stock: 74702321.25MXW Datasheet

Current PartRFQ

02321.25MXEP

Littelfuse Inc.In Stock: 107902321.25MXEP Datasheet

MFR RecommendedRFQ

02321.25MXP

LittelfuseIn Stock: 116102321.25MXP Datasheet

Parametric EquivalentRFQ

02341.25MXBP

Littelfuse Inc.In Stock: 82002341.25MXBP Datasheet

Parametric EquivalentRFQ

02341.25MXP

Littelfuse Inc.In Stock: 109302341.25MXP Datasheet

Parametric EquivalentRFQ

MSC-1.25A

OptiFuseIn Stock: 2403MSC-1.25A Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict adherence to the following electrical and mechanical parameters:

Primary Substitution 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: Medium Blow (exact match required)
• Breaking Capacity: 100 A (exact match required)
• Operating Temperature Range: -55°C to 125°C (exact match required)

Secondary Compatibility Factors:

• Package / Case: 5mm x 20mm (exact match required for mechanical fit)
• Mounting Type: Requires Holder (exact match required for assembly compatibility)

All substitute parts listed below satisfy these criteria. Variations in melting I²t, DC cold resistance, and approval agencies do not affect substitution eligibility when primary parameters are identical.

Parameter Comparison

Engineering Selection Recommendations

Direct Substitutes (Identical Mounting Type):

The parts 02321.25MXP, 02341.25MXBP, 02341.25MXP, and MSC-1.25A are direct functional equivalents to the obsolete 02321.25MXW. All four parts are active products with ROHS3 compliance and maintain identical electrical specifications and mechanical form factors. Selection among these four parts depends on supply chain availability and approval agency requirements specific to the application.

Littelfuse 02321.25MXP and 02341.25MXP offer the broadest approval coverage (CE, CSA, K-MARK, PSE, UL certifications available across the series). OptiFuse MSC-1.25A provides cULus and UL 248 certification with the highest current inventory (2316 units).

Alternative Mounting Configuration:

The Littelfuse 02321.25MXEP is electrically equivalent but features through-hole axial mounting instead of requiring a separate holder. This part is suitable only for applications where PCB-mounted through-hole assembly is acceptable and where the slightly larger physical dimensions (5.80mm diameter x 22.50mm length versus 5.20mm x 20.00mm) do not create space constraints.

Frequently Asked Questions (FAQ)

Q: Can 02321.25MXEP replace 02321.25MXW in existing assemblies?

A: 02321.25MXEP is electrically equivalent but has different mounting requirements. The original 02321.25MXW requires a separate fuse holder, while 02321.25MXEP is designed for through-hole PCB mounting. Substitution is possible only if the assembly design can accommodate through-hole mounting and the slightly larger physical dimensions.

Q: What is the difference between Littelfuse Series 232 and Series 234 fuses?

A: Both series maintain identical electrical parameters (1.25 A, 250 V, medium-blow response). Series 234 parts (02341.25MXBP, 02341.25MXP) have different melting I²t and DC cold resistance characteristics compared to Series 232, but these differences do not affect substitution eligibility for applications requiring 1.25 A, 250 V protection.

Q: Are all substitute parts RoHS compliant?

A: Yes. All active substitute parts listed (02321.25MXP, 02341.25MXBP, 02341.25MXP, MSC-1.25A, and 02321.25MXEP) are ROHS3 compliant. The original 02321.25MXW is RoHS non-compliant, making substitution necessary for applications subject to RoHS regulations.

Q: Which substitute part has the highest inventory availability?

A: OptiFuse MSC-1.25A has the highest current inventory at 2316 units. Littelfuse 02321.25MXP has 1073 units, and 02341.25MXP has 1002 units in stock.

Q: Do all substitute parts have identical approval certifications?

A: No. Approval agencies vary by part. Littelfuse 02341.25MXBP and 02341.25MXP carry the broadest certification coverage (CE, CSA, K-MARK, PSE, UL). OptiFuse MSC-1.25A carries cULus and UL 248 certification. Littelfuse 02321.25MXP carries CE, KC, and PSE certification. Select based on application-specific regulatory requirements.

Q: Can MSC-1.25A from OptiFuse be used interchangeably with Littelfuse parts?

A: Yes. MSC-1.25A meets all electrical and mechanical substitution criteria. It is a parametric equivalent with identical current rating, voltage rating, response time, package dimensions, and mounting type. Supplier qualification and approval agency requirements should guide final selection.