Littelfuse 031802.5H Glass Cartridge Fuse - Equivalent & Substitute Parts

Part Overview

The Littelfuse 031802.5H is a 2.5 A, 250 V AC/DC fast-blow glass cartridge fuse in the 3AB/3AG package format (1/4" x 1-1/4" axial). This component is classified as obsolete, making equivalent substitute parts necessary for ongoing system maintenance and new designs. The part operates as a protective device in electrical circuits, interrupting current flow when rated amperage is exceeded. Active equivalent models from Littelfuse provide direct functional replacement with enhanced specifications and current product support.

Substiute Parts

031802.5H

LittelfuseIn Stock: 1186031802.5H Datasheet

Current PartRFQ

031802.5HXP

Littelfuse Inc.In Stock: 976031802.5HXP Datasheet

DirectRFQ

031802.5MXP

Littelfuse Inc.In Stock: 791031802.5MXP Datasheet

Parametric EquivalentRFQ

031802.5VXP

Littelfuse Inc.In Stock: 1017031802.5VXP Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the obsolete 031802.5H is determined by strict equivalence across the following parameters:

• Current Rating: 2.5 A (exact match required)
• Voltage Rating: 250 V AC (exact match required)
• Package / Case: 3AB, 3AG, 1/4" x 1-1/4" (Axial) (exact match required)
• Response Time: Fast Blow (exact match required)
• Melting I²t: 9.54 (exact match required)
• Physical Dimensions: 0.275" Dia x 1.288" L (exact match required)

All three substitute parts—031802.5HXP, 031802.5MXP, and 031802.5VXP—meet these criteria and are direct functional equivalents. These active parts maintain identical electrical performance while offering improved specifications in breaking capacity, temperature range, and regulatory compliance compared to the obsolete original.

Parameter Comparison

Engineering Selection Recommendations

All three substitute parts—031802.5HXP, 031802.5MXP, and 031802.5VXP—are direct functional replacements for the obsolete 031802.5H. Selection among these active equivalents should be based on:

Product Status: All substitutes are active products with current manufacturer support, eliminating obsolescence risk associated with the original part.

Regulatory Compliance: The substitute parts hold ROHS3 compliance and REACH unaffected status, meeting modern environmental and safety standards. The original part is RoHS non-compliant. All substitutes carry expanded approval certifications (CE, CSA, KC, PSE, UL) compared to the original (CSA, UL only).

Electrical Performance: All substitutes maintain identical current rating, voltage rating, response time, melting I²t, and physical dimensions. The substitutes offer improved breaking capacity (100 A versus 35 A), providing enhanced circuit protection margins.

Temperature Range: Substitute parts specify operating temperature range of -55°C to 125°C, whereas the original part does not specify this parameter. This expanded range supports broader application environments.

Packaging: All substitutes are available in bulk packaging, consistent with production and replacement workflows.

Frequently Asked Questions (FAQ)

Q: Can 031802.5HXP, 031802.5MXP, and 031802.5VXP be used interchangeably with 031802.5H?

A: Yes. All three substitute parts are direct functional equivalents. They maintain identical current rating (2.5 A), voltage rating (250 V AC), response time (fast blow), package format (3AB/3AG), melting I²t (9.54), and physical dimensions (0.275" Dia x 1.288" L). They are mechanically and electrically compatible with circuits designed for 031802.5H.

Q: What is the difference between the three substitute parts?

A: The three substitute parts—031802.5HXP, 031802.5MXP, and 031802.5VXP—are parametrically identical. All share the same electrical specifications, physical dimensions, breaking capacity (100 A), operating temperature range (-55°C to 125°C), and regulatory certifications. Differences exist only in inventory availability and packaging designation.

Q: Why does the original 031802.5H have a lower breaking capacity (35 A) than the substitutes (100 A)?

A: Breaking capacity is the maximum current the fuse can safely interrupt without damage. The substitutes' higher breaking capacity (100 A) provides enhanced circuit protection margins and improved safety performance. This does not affect the fuse's primary function—interrupting current at the rated 2.5 A threshold.

Q: Are the substitute parts RoHS compliant?

A: Yes. All three substitute parts are ROHS3 compliant. The original 031802.5H is RoHS non-compliant. This compliance status is relevant for applications subject to environmental regulations in the EU and other jurisdictions.

Q: What certifications do the substitute parts hold?

A: The substitute parts hold CE, CSA, KC, PSE, and UL certifications. The original part holds CSA and UL certifications only. The expanded certification set reflects current global safety and regulatory standards.

Q: Can I use these fuses in high-temperature environments?

A: The substitute parts specify an operating temperature range of -55°C to 125°C. Applications requiring operation outside this range require evaluation against specific environmental conditions. The original part does not specify operating temperature limits.

Q: Are the physical dimensions identical between the original and substitute parts?

A: Yes. All parts maintain identical physical dimensions: 0.275" diameter x 1.288" length (6.99mm x 32.72mm). They are mechanically interchangeable in 3AB/3AG package footprints.