Littelfuse 0257040.L Automotive Fuse - Equivalent & Substitute Parts

Part Overview

The Littelfuse 0257040.L is a 40A 32VDC automotive blade fuse designed for ATO/ATC holder applications. This part is classified as obsolete, making identification of suitable substitutes essential for ongoing maintenance and repair operations. The fuse provides overcurrent protection in automotive electrical systems with a breaking capacity of 1kA and operates across a temperature range of -40°C to 105°C. Substitute parts must maintain identical electrical ratings and mechanical compatibility to ensure proper circuit protection without modification to existing fuse holders.

Substiute Parts

0257040.L

LittelfuseIn Stock: 8220257040.L Datasheet

Current PartRFQ

0287040.PXCN

Littelfuse Inc.In Stock: 934190287040.PXCN Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the Littelfuse 0257040.L is determined by strict equivalence across the following critical parameters:

• Current Rating: 40 A (exact match required)
• Voltage Rating - DC: 32 V (exact match required)
• Package / Case: Blade, ATO/ATC (mechanical compatibility with existing holders)
• Melting I²t: 3310 (thermal response characteristic)
• DC Cold Resistance: 0.00144 Ohms (electrical performance)
• Operating Temperature Range: -40°C ~ 105°C (environmental suitability)

The substitute part 0287040.PXCN meets all critical electrical and mechanical parameters. Both parts are manufactured by Littelfuse, operate within identical voltage and current specifications, utilize the same ATO/ATC blade form factor, and maintain equivalent thermal and resistance characteristics. The substitute part is classified as active product status with current manufacturing availability.

Parameter Comparison

Engineering Selection Recommendations

The Littelfuse 0287040.PXCN is the direct substitute for the obsolete 0257040.L. Both parts maintain identical electrical specifications (40A, 32VDC), thermal characteristics (I²t = 3310), and mechanical form factor (ATO/ATC blade). Dimensional tolerances between the two parts are within acceptable limits for standard ATO/ATC fuse holders (maximum variation 0.002" in length and width, 0.004" in height).

The substitute part carries active product status with established manufacturing and supply chains, ensuring long-term availability. Regulatory compliance is maintained through ROHS3 certification on both parts. The substitute part holds CSA and UL approvals, providing equivalent or enhanced certification coverage compared to the original part's cULus approval.

Frequently Asked Questions (FAQ)

Q: Can the 0287040.PXCN be used as a direct replacement in existing fuse holders designed for the 0257040.L?

A: Yes. Both parts utilize the ATO/ATC blade form factor with dimensions within standard tolerance ranges for automotive fuse holders. The mechanical compatibility is confirmed through equivalent package specifications.

Q: Are the electrical characteristics identical between the two parts?

A: Yes. Both parts are rated for 40A at 32VDC with identical melting I²t values of 3310 and DC cold resistance of 0.00144 Ohms. Thermal response and overcurrent protection characteristics are equivalent.

Q: What is the significance of the product status difference (Obsolete vs. Active)?

A: The 0257040.L is no longer manufactured. The 0287040.PXCN is actively produced and stocked, ensuring availability for replacement and repair applications. Both parts meet identical functional requirements.

Q: Are there any compliance or certification differences?

A: Both parts are ROHS3 compliant. The substitute part holds CSA and UL approvals, while the original part holds cULus approval. All certifications are appropriate for automotive fuse applications.

Q: What are the dimensional tolerances between these parts?

A: The substitute part dimensions are 0.752" L x 0.201" W x 0.484" H compared to 0.750" L x 0.200" W x 0.480" H for the original. These variations (0.002" maximum in length and width, 0.004" in height) fall within standard ATO/ATC holder tolerances and do not affect mechanical fit or electrical performance.