Littelfuse 03181.25MXP Glass Cartridge Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 03181.25MXP is a 1.25 A, 250 V AC/DC fast-blow glass cartridge fuse designed for through-hole mounting in 3AB and 3AG package configurations. This component is classified as Active product status and is widely used in industrial control circuits, power distribution systems, and consumer electronics requiring overcurrent protection. Substitute parts are identified when equivalent electrical characteristics, mechanical dimensions, and regulatory compliance certifications match the original specification, ensuring direct interchangeability without circuit redesign.

Substiute Parts

03181.25MXP

Littelfuse Inc.In Stock: 114103181.25MXP Datasheet

Current PartRFQ

03181.25HXP

Littelfuse Inc.In Stock: 125503181.25HXP Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 03181.25MXP are identified based on strict equivalence of the following critical parameters:

• 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: Fast Blow (exact match required)
• Package / Case: 3AB, 3AG, 1/4" x 1-1/4" (Axial) (exact match required)
• Mounting Type: Through Hole (exact match required)
• Breaking Capacity @ Rated Voltage: 100 A (exact match required)
• Melting I²t: 1.45 (exact match required)
• Operating Temperature Range: -55°C ~ 125°C (exact match required)
• Size / Dimension: 0.275" Dia x 1.288" L (6.99mm x 32.72mm) (exact match required)
• DC Cold Resistance: 0.1385 Ohms (exact match required)
• Approval Agencies: CE, CSA, KC, PSE, UL (all certifications required)
• RoHS Status: ROHS3 Compliant (exact match required)

Only parts meeting all these criteria are classified as direct parametric equivalents and may be substituted without modification to the circuit or mechanical assembly.

Parameter Comparison

Engineering Selection Recommendations

The Littelfuse 03181.25HXP (part number variant) is a direct parametric equivalent to the 03181.25MXP. Both parts are manufactured by Littelfuse Inc., maintain Active product status, and carry identical electrical, mechanical, and thermal specifications. Both components hold the same regulatory certifications (CE, CSA, KC, PSE, UL) and comply with ROHS3 requirements, confirming suitability for applications requiring equivalent environmental and safety compliance.

Selection between these two part numbers may be based on inventory availability, lead time, or procurement source, as no technical differentiation exists between them. The 03181.25HXP maintains 1167 pieces in stock compared to 1086 pieces for the 03181.25MXP, which may influence supply chain decisions.

Frequently Asked Questions (FAQ)

Q: Can the 03181.25HXP be used as a direct replacement for the 03181.25MXP in existing circuits?

A: Yes. The 03181.25HXP is a direct parametric equivalent with identical current rating (1.25 A), voltage rating (250 V AC), fuse type (cartridge, glass), response time (fast blow), package configuration (3AB, 3AG), and all electrical characteristics. No circuit modification is required.

Q: Are the physical dimensions identical between these two part numbers?

A: Yes. Both parts share the same package dimensions of 0.275" diameter by 1.288" length (6.99mm x 32.72mm), ensuring mechanical compatibility with existing through-hole fuse holders and PCB layouts.

Q: Do both parts carry the same regulatory certifications?

A: Yes. Both the 03181.25MXP and 03181.25HXP hold identical approval certifications: CE, CSA, KC, PSE, and UL. Both are ROHS3 compliant and REACH unaffected, meeting equivalent regulatory requirements for industrial and consumer applications.

Q: What is the difference between these two part numbers if all specifications are identical?

A: The specifications provided indicate these are parametric equivalents from the same manufacturer and series (318). Differences, if any, may relate to internal manufacturing processes, packaging batches, or distribution channels, but no electrical, mechanical, or performance differentiation exists based on the provided technical data.

Q: Can these fuses be used in applications rated for different voltage levels?

A: No. Both parts are rated for 250 V AC operation. Use only in circuits designed for this voltage rating. Application in circuits exceeding 250 V AC or in DC-only applications requires verification of DC voltage rating specifications.

Q: What is the significance of the 1.45 melting I²t value?

A: The melting I²t of 1.45 defines the thermal energy required to melt the fuse element. This parameter, combined with the 1.25 A current rating and fast-blow response time, determines the fuse's protection characteristics and coordination with circuit overcurrent protection schemes.