Equivalent & Substitute Parts for 3AP 6-R Glass Cartridge Fuse

Part Overview

The Bel Fuse Inc. 3AP 6-R is a 6 A, 250 V AC/DC fast-blow glass cartridge fuse with 3AB/3AG package configuration and through-hole mounting. This component is classified as obsolete, making equivalent substitute parts necessary for ongoing system maintenance and new design implementations. The Littelfuse Inc. 318 series provides direct functional equivalents with active product status and expanded certification coverage.

Substiute Parts

3AP 6-R

Bel Fuse Inc.In Stock: 9383AP 6-R Datasheet

Current PartRFQ

0318006.HXP

Littelfuse Inc.In Stock: 12970318006.HXP Datasheet

DirectRFQ

0318006.MXP

Littelfuse Inc.In Stock: 9180318006.MXP Datasheet

DirectRFQ

0318006.VXP

Littelfuse Inc.In Stock: 8190318006.VXP Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 3AP 6-R is determined by strict equivalence across the following parameters:

• Current Rating: 6 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: 200 A (exact match required)
• Operating Temperature Range: -55°C ~ 125°C (exact match required)

All three Littelfuse 318 series parts (0318006.HXP, 0318006.MXP, 0318006.VXP) meet these criteria and are classified as direct substitutes.

Parameter Comparison

Engineering Selection Recommendations

The Littelfuse 318 series parts (0318006.HXP, 0318006.MXP, 0318006.VXP) are qualified substitutes for the obsolete 3AP 6-R. All three alternatives maintain active product status and provide expanded regulatory compliance with UL and KC certifications in addition to the CE, CSA, and PSE certifications of the original part. The dimensional variance (0.003" diameter and 0.008" length increase) remains within typical mechanical tolerances for 3AB/3AG cartridge fuse holders. The increased melting I²t value (118 versus 107) and DC cold resistance (0.0178 versus 0.015 Ohms) represent minor performance variations within the fast-blow fuse category and do not affect functional equivalence for standard circuit protection applications.

Frequently Asked Questions (FAQ)

Q: Can the Littelfuse 318 series parts directly replace the Bel Fuse 3AP 6-R in existing designs?

A: Yes. The 0318006.HXP, 0318006.MXP, and 0318006.VXP maintain identical electrical ratings (6 A, 250 V AC), fuse type (cartridge, glass), response time (fast blow), and package configuration (3AB, 3AG, 1/4" x 1-1/4" axial). Through-hole mounting compatibility is confirmed. The minor dimensional increase and resistance variation do not affect mechanical fit or circuit protection performance.

Q: What is the difference between 0318006.HXP, 0318006.MXP, and 0318006.VXP?

A: All three parts are functionally equivalent with identical electrical and mechanical specifications. The suffix designations (HXP, MXP, VXP) indicate different packaging or distribution channels from Littelfuse Inc. Selection among these three substitutes may be based on inventory availability or procurement preference.

Q: Are the Littelfuse substitutes certified for the same applications as the original 3AP 6-R?

A: The Littelfuse parts carry CE, CSA, KC, PSE, and UL certifications, providing broader regulatory coverage than the original part (CE, CSA, cULus, PSE). Both the original and substitute parts are ROHS3 compliant and REACH unaffected, confirming environmental compliance equivalence.

Q: What is the significance of the melting I²t difference (107 versus 118)?

A: The melting I²t value characterizes the thermal energy required to melt the fuse element. The 10% increase in the Littelfuse parts remains within the fast-blow fuse category and does not alter the protective function for circuits designed around the 6 A, 250 V specification.

Q: Are there any mechanical fit concerns with the dimensional variance?

A: The Littelfuse parts measure 0.275" diameter and 1.288" length compared to the 3AP 6-R at 0.272" diameter and 1.280" length. These differences (0.003" and 0.008" respectively) are within standard mechanical tolerances for 3AB/3AG cartridge fuse holders and do not affect insertion or retention.