3ABP 1.25-R Ceramic Fuse Equivalent & Substitute Parts

Part Overview

The 3ABP 1.25-R is a 1.25 A ceramic cartridge fuse manufactured by Bel Fuse Inc., rated for 250 V AC/DC operation with fast-blow response characteristics. This component is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing system maintenance and component procurement. The fuse is designed for through-hole mounting in 3AB/3AG form factor applications requiring reliable overcurrent protection in industrial and commercial equipment.

Substiute Parts

3ABP 1.25-R

Bel Fuse Inc.In Stock: 11433ABP 1.25-R Datasheet

Current PartRFQ

8020.5069.PT

SCHURTER Inc.In Stock: 15578020.5069.PT Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 3ABP 1.25-R is determined by the following critical parameters:

Mandatory Matching Parameters:

• Current Rating: 1.25 A (exact match required)
• Fuse Type: Cartridge, Ceramic
• Package / Case: 3AB, 3AG, 1/4" x 1-1/4" (Axial)
• Mounting Type: Through Hole
• Response Time: Fast Blow

Allowable Variation Parameters:

• Voltage Rating (AC): May exceed 250 V (backward compatible for lower-voltage applications)
• Breaking Capacity: May exceed 100 A
• Melting I²t: May vary within acceptable tolerance
• Operating Temperature Range: May differ if application requirements are met
• Approvals: Subset of original certifications acceptable if application-specific requirements are satisfied

The substitute part 8020.5069.PT from SCHURTER Inc. meets all mandatory matching criteria while providing enhanced voltage rating (500 V) and breaking capacity (1.5 kA), making it suitable for applications where the original 3ABP 1.25-R is no longer available.

Parameter Comparison

Engineering Selection Recommendations

The 8020.5069.PT from SCHURTER Inc. is the qualified substitute for the obsolete 3ABP 1.25-R. Selection is based on the following engineering criteria:

Compliance & Certification: The substitute maintains ROHS3 compliance and holds cURus approval, satisfying regulatory requirements for applications where the original part was approved. The original 3ABP 1.25-R carried CE, CSA, cURus, and PSE certifications; the substitute's cURus approval covers the primary North American safety standard.

Electrical Compatibility: Both components share identical current rating (1.25 A) and fast-blow response characteristics. The substitute's 500 V AC rating provides enhanced voltage margin over the original 250 V specification, making it suitable for applications operating at or below the original voltage rating.

Physical Compatibility: Dimensional specifications are equivalent within manufacturing tolerance (original: 0.272" Dia x 1.280" L; substitute: 0.270" Dia x 1.291" L), ensuring mechanical fit in existing 3AB/3AG fuse holders.

Performance Considerations: The substitute exhibits slightly higher melting I²t (2.9 vs. 2.45), indicating marginally slower thermal response. The operating temperature range of the substitute (-40°C ~ 85°C) is narrower than the original (-55°C ~ 125°C); applications requiring operation below -40°C or above 85°C require alternative evaluation.

Frequently Asked Questions (FAQ)

Q: Can the 8020.5069.PT substitute for the 3ABP 1.25-R in all applications?

A: The 8020.5069.PT is electrically and mechanically compatible for applications operating at or below 250 V AC and within the temperature range of -40°C to 85°C. Applications requiring operation outside this temperature range or those with specific approval requirements (PSE, for example) require individual assessment.

Q: What is the significance of the higher voltage rating (500 V) on the substitute?

A: The 500 V rating on the 8020.5069.PT indicates the component is rated for higher voltage stress. For applications using 250 V or lower, this provides additional safety margin and does not affect performance. The fuse will operate identically at the original 250 V specification.

Q: Are there dimensional differences between the two fuses?

A: Dimensional variations are minimal and within standard manufacturing tolerance for 3AB/3AG form factor components. Both fuses are designed for the same mechanical envelope and will fit standard 3AB/3AG fuse holders.

Q: How does the melting I²t difference affect fuse selection?

A: The melting I²t value (2.45 for the original vs. 2.9 for the substitute) represents the thermal energy required to melt the fuse element. The substitute's slightly higher value indicates marginally slower thermal response. For applications with precise overcurrent protection timing requirements, this difference should be evaluated against system protection coordination curves.

Q: What approvals does the substitute carry?

A: The 8020.5069.PT carries cURus certification. The original 3ABP 1.25-R carried CE, CSA, cURus, and PSE approvals. Applications requiring PSE certification or other specific regional approvals should verify substitute acceptability with system designers or regulatory authorities.

Q: Is the substitute available in the same packaging as the original?

A: The substitute is supplied in bulk packaging, whereas the original part number does not specify packaging format in the provided data. Both components use identical 3AB/3AG cartridge form factor suitable for through-hole mounting.