Equivalent & Substitute Parts for 3AB 20-R Ceramic Fuse

Part Overview

The 3AB 20-R is a 20 A, 250 V AC ceramic cartridge fuse manufactured by Bel Fuse Inc. This fast-blow fuse is designed for AC applications and requires a 3AB or 3AG fuse holder. The part is currently active in production with 1,864 units in stock. Equivalent and substitute parts are identified to support procurement flexibility, inventory management, and supply chain continuity for applications requiring 20 A, 250 V AC ceramic cartridge fuses in the 3AB/3AG form factor.

Substiute Parts

3AB 20-R

Bel Fuse Inc.In Stock: 19443AB 20-R Datasheet

Current PartRFQ

0314020.MXP

Littelfuse Inc.In Stock: 81230314020.MXP Datasheet

DirectRFQ

BK/ABC-20-R

Eaton - Electronics DivisionIn Stock: 1731BK/ABC-20-R Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 3AB 20-R are qualified based on the following criteria:

Primary Matching Parameters:

• Current Rating: 20 A (exact match required)
• Voltage Rating - AC: 250 V (exact match required)
• Fuse Type: Cartridge, Ceramic (exact match required)
• Package / Case: 3AB, 3AG, 1/4" x 1-1/4" (exact match required)
• Response Time: Fast Blow (exact match required)

Secondary Compatibility Parameters:

• Mounting Type: Requires Holder (compatible with same holder systems)
• Physical Dimensions: 0.250" Dia x 1.250" to 1.252" L (interchangeable within tolerance)
• RoHS Compliance: ROHS3 Compliant (regulatory alignment)

The substitute parts identified below meet all primary matching parameters and are therefore electrically and mechanically compatible with the 3AB 20-R for AC applications at 250 V, 20 A.

Parameter Comparison

Engineering Selection Recommendations

All three parts are active products with ROHS3 compliance and are suitable for 250 V AC, 20 A ceramic cartridge fuse applications in 3AB/3AG holders.

0314020.MXP (Littelfuse Inc.): This part provides dual AC/DC voltage ratings (250 V AC, 125 V DC) and holds CE, CSA, PSE, and UL certifications. It is appropriate for applications requiring DC voltage capability or broader international regulatory coverage.

BK/ABC-20-R (Eaton - Electronics Division): This part also provides dual AC/DC voltage ratings (250 V AC, 125 V DC) and holds CSA and UL certifications. It is appropriate for North American applications requiring UL certification.

3AB 20-R (Bel Fuse Inc.): This part is specified for AC applications and holds CE and cURus certifications. It is appropriate for applications with AC-only requirements and European regulatory compliance needs.

Selection between these parts should be based on application voltage requirements (AC only versus AC/DC), required regulatory certifications, and supply chain availability.

Frequently Asked Questions (FAQ)

Q: Can 0314020.MXP or BK/ABC-20-R be used as direct replacements for 3AB 20-R?

A: Yes, both parts are direct substitutes for AC applications at 250 V, 20 A. All three parts share identical current rating, AC voltage rating, fuse type, response time, and package specifications. Physical dimensions are within tolerance (1.250" to 1.252" length). The substitute parts offer additional DC voltage capability, which does not affect AC-only applications.

Q: What are the key differences between these three parts?

A: The primary differences are DC voltage rating, breaking capacity, melting I²t, and regulatory certifications. The 3AB 20-R does not specify a DC voltage rating and is optimized for AC applications. The 0314020.MXP and BK/ABC-20-R both support 125 V DC in addition to 250 V AC. Breaking capacity and melting I²t values differ, reflecting different design characteristics. Regulatory certifications vary by manufacturer and target market.

Q: Are the physical dimensions identical?

A: The diameter is identical at 0.250" (6.35mm). The length varies slightly: 3AB 20-R is 1.252" (31.80mm), while 0314020.MXP and BK/ABC-20-R are 1.250" (31.75mm). This 0.002" (0.05mm) difference is within standard mechanical tolerance for cartridge fuses and does not affect holder compatibility.

Q: Which certifications apply to each part?

A: 3AB 20-R holds CE and cURus certifications. 0314020.MXP holds CE, CSA, PSE, and UL certifications. BK/ABC-20-R holds CSA and UL certifications. Selection should align with regional regulatory requirements for the end application.

Q: Can these parts be used interchangeably in the same fuse holder?

A: Yes. All three parts are designed for 3AB and 3AG fuse holders and share the same 0.250" diameter and 1/4" x 1-1/4" form factor. They are mechanically interchangeable within standard tolerance.

Q: What is the significance of the different melting I²t values?

A: Melting I²t is a thermal characteristic that describes the fuse element's response to overcurrent. The 3AB 20-R has a melting I²t of 1598, while 0314020.MXP is 631 and BK/ABC-20-R is 550.8. These differences reflect different fuse element designs and thermal mass. For AC-only applications, the 3AB 20-R's higher I²t may provide different protection characteristics. Application-specific circuit protection requirements should determine which part is appropriate.