3AG 2.5 Fuse Cartridge Equivalent & Substitute Parts

Part Overview

The 3AG 2.5 is a 2.5 A, 250 V AC/DC fast-blow glass cartridge fuse manufactured by Bel Fuse Inc. This component is classified as obsolete, requiring identification of active equivalent alternatives for ongoing system support and procurement. The 3AG form factor with 1/4" x 1-1/4" dimensions and cartridge glass construction remains a standard specification in industrial and consumer electronics applications requiring overcurrent protection in AC/DC circuits.

Substiute Parts

3AG 2.5

Bel Fuse Inc.In Stock: 8943AG 2.5 Datasheet

Current PartRFQ

3AG 2.5-R

Bel Fuse Inc.In Stock: 39973AG 2.5-R Datasheet

DirectRFQ

031202.5HXP

Littelfuse Inc.In Stock: 2634031202.5HXP Datasheet

SimilarRFQ

FSA-2.5A

OptiFuseIn Stock: 2994FSA-2.5A Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 3AG 2.5 fuse is determined by strict alignment of the following parameters:

• Current Rating: 2.5 A (exact match required)
• Voltage Rating: 250 V AC (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" (exact match required)
• Mounting Type: Requires Holder (exact match required)
• Operating Temperature Range: -55°C ~ 125°C (minimum coverage required)

All substitute parts listed below meet these core electrical and mechanical parameters. Variations in secondary parameters such as breaking capacity, melting I²t, DC cold resistance, and approval agencies are documented for engineering evaluation but do not disqualify substitution eligibility.

Parameter Comparison

Engineering Selection Recommendations

3AG 2.5-R (Bel Fuse Inc.) is the primary direct substitute. This part maintains identical electrical and mechanical specifications to the obsolete 3AG 2.5, with the advantage of active product status and ROHS3 compliance. Approval certifications include CE, CSA, cURus, and PSE. This option provides continuity with the original manufacturer while meeting current regulatory requirements.

031202.5HXP (Littelfuse Inc.) is a qualified alternative from a major fuse manufacturer. All core electrical and mechanical parameters align with the original specification. The part carries ROHS3 compliance and comprehensive approval certifications (CE, CSA, KC, PSE, UL). Breaking capacity is rated at 100A versus the original 200A, and melting I²t is 9.54 versus 12. These differences do not affect substitution eligibility but should be evaluated against specific circuit protection requirements.

FSA-2.5A (OptiFuse) meets all mandatory electrical and mechanical parameters. This part is ROHS3 compliant with cULus and UL 248 certifications. Breaking capacity is 100A, and melting I²t is 14.21. This option provides an alternative source from an established fuse manufacturer.

Frequently Asked Questions (FAQ)

Q: Can the 3AG 2.5-R directly replace the obsolete 3AG 2.5?

A: Yes. The 3AG 2.5-R maintains identical current rating (2.5 A), voltage rating (250 V AC), fuse type (cartridge glass), response time (fast blow), package dimensions (1/4" x 1-1/4"), and operating temperature range (-55°C ~ 125°C). It is the direct equivalent from the original manufacturer.

Q: What is the difference between the 031202.5HXP and the original 3AG 2.5?

A: The 031202.5HXP matches all core electrical and mechanical specifications. Differences include breaking capacity (100A versus 200A) and melting I²t (9.54 versus 12). Physical dimensions are 0.250" Dia x 1.250" L versus 0.250" Dia x 1.252" L, a 0.002" length variation within typical manufacturing tolerance.

Q: Are all substitute parts RoHS compliant?

A: The 3AG 2.5-R, 031202.5HXP, and FSA-2.5A are all ROHS3 compliant. The original 3AG 2.5 is RoHS non-compliant. Compliance status should be verified against system-level regulatory requirements.

Q: Do these fuses require the same holder?

A: Yes. All listed parts require the 3AB or 3AG holder due to identical 1/4" x 1-1/4" cartridge dimensions. Existing holder hardware is compatible with all substitute parts.

Q: Which substitute offers the widest approval certifications?

A: The 031202.5HXP carries five approval agencies (CE, CSA, KC, PSE, UL), providing the broadest regulatory coverage for international applications.