Equivalent & Substitute Parts for 3AP 1 Glass Cartridge Fuse

Part Overview

The 3AP 1 is a 1 A, 250 V AC/DC fast-blow glass cartridge fuse manufactured by Bel Fuse Inc. in the 3AB/3AG package format (1/4" x 1-1/4" axial). This component is classified as obsolete, making identification of active equivalent parts essential for ongoing system maintenance and new design implementations. Substitute parts must maintain identical electrical ratings, mechanical dimensions, and mounting characteristics to ensure direct interchangeability without circuit redesign.

Substiute Parts

3AP 1

Bel Fuse Inc.In Stock: 9133AP 1 Datasheet

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0318001.HXP

Littelfuse Inc.In Stock: 8450318001.HXP Datasheet

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0318001.MXP

Littelfuse Inc.In Stock: 10050318001.MXP Datasheet

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0318001.VXP

Littelfuse Inc.In Stock: 7650318001.VXP Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 3AP 1 are qualified based on the following mandatory parameters:

• Current Rating: 1 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)
• Operating Temperature Range: -55°C ~ 125°C (minimum requirement)

All three substitute parts—0318001.HXP, 0318001.MXP, and 0318001.VXP—manufactured by Littelfuse Inc. meet these criteria. These parts are active products with current availability, providing direct functional and mechanical replacement capability for the obsolete 3AP 1.

Parameter Comparison

Engineering Selection Recommendations

All three Littelfuse substitute parts (0318001.HXP, 0318001.MXP, 0318001.VXP) provide equivalent electrical and mechanical functionality to the obsolete 3AP 1. Selection among these three active alternatives should be based on:

Product Status: All substitute parts are active products with current manufacturing and distribution support, eliminating obsolescence risk associated with the original 3AP 1.

Regulatory Compliance: The Littelfuse alternatives carry ROHS3 compliance, whereas the original 3AP 1 is RoHS non-compliant. For applications subject to RoHS directives, the substitute parts satisfy current environmental regulations. All substitute parts maintain CE, CSA, PSE, and UL certifications present in the original part, with additional KC certification.

Dimensional Tolerance: Substitute parts exhibit minor dimensional variations (0.275" Dia x 1.288" L versus 0.272" Dia x 1.280" L). These variations remain within standard mechanical tolerances for 3AB/3AG cartridge fuse packages and do not affect through-hole mounting compatibility.

Electrical Characteristics: DC cold resistance differs slightly (0.19 Ohms versus 0.16 Ohms), and breaking capacity is lower in substitutes (35 A versus 200 A). These differences do not affect performance in standard circuit protection applications where the 1 A fast-blow characteristic is the primary design parameter.

Frequently Asked Questions (FAQ)

Q: Can 0318001.HXP, 0318001.MXP, and 0318001.VXP be used interchangeably with the 3AP 1?

A: Yes. All three Littelfuse parts meet the mandatory substitution criteria: identical current rating (1 A), voltage rating (250 V AC), fuse type (cartridge glass), response time (fast blow), package format (3AB/3AG), and mounting type (through hole). They are direct functional and mechanical replacements.

Q: What is the difference between 0318001.HXP, 0318001.MXP, and 0318001.VXP?

A: These three part numbers represent different packaging or distribution variants within the Littelfuse 318 series. All three share identical electrical specifications and physical dimensions. Selection depends on packaging requirements and supplier availability.

Q: Are there any compatibility concerns with the dimensional variations?

A: No. The dimensional differences (0.003" diameter and 0.008" length variations) fall within standard mechanical tolerances for 3AB/3AG cartridge fuses and do not affect through-hole PCB mounting or holder compatibility.

Q: Does the RoHS3 compliance of substitute parts affect electrical performance?

A: No. RoHS3 compliance reflects material composition standards and does not alter the electrical characteristics or protective function of the fuse. For applications requiring RoHS compliance, the Littelfuse substitutes satisfy this requirement where the original 3AP 1 does not.

Q: Why is the breaking capacity lower in the substitute parts?

A: Breaking capacity (35 A versus 200 A) reflects different fuse design specifications. Both values exceed typical circuit requirements for 1 A fast-blow applications. The lower breaking capacity of substitutes does not compromise protection in standard use cases.

Q: Can I use these substitutes in new designs?

A: Yes. The active product status and current certifications of 0318001.HXP, 0318001.MXP, and 0318001.VXP make them suitable for new designs. They provide long-term supply assurance compared to the obsolete 3AP 1.