Littelfuse 0255004.M Equivalent & Substitute Parts

Part Overview

The Littelfuse 0255004.M is a 4A 125VAC/VDC board mount axial fuse with fast blow response time, designed for through-hole mounting applications. This component is classified as obsolete, making identification of suitable substitute parts essential for ongoing design support and production continuity. The PICO® 255 series fuse provides protection in low-voltage DC and AC circuits with a breaking capacity of 50A AC and 300A DC.

Substiute Parts

0255004.M

Littelfuse Inc.In Stock: 10190255004.M Datasheet

Current PartRFQ

0251004.MXL

Littelfuse Inc.In Stock: 46500251004.MXL Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

The Littelfuse 0251004.MXL qualifies as a direct substitute for the 0255004.M based on the following critical electrical and mechanical parameters:

Matching Parameters:

• Current Rating: 4 A (identical)
• Voltage Rating - AC: 125 V (identical)
• Voltage Rating - DC: 125 V (identical)
• Response Time: Fast Blow (identical)
• Mounting Type: Through Hole (identical)
• Fuse Type: Board Mount (Cartridge Style Excluded) (identical)
• Package / Case: Axial (identical)
• Breaking Capacity @ Rated Voltage: 50A AC, 300A DC (identical)

The 0251004.MXL represents an active product from the PICO® II 251 series, providing functional equivalence with enhanced compliance certifications and extended operating temperature range.

Parameter Comparison

Engineering Selection Recommendations

The 0251004.MXL is the manufacturer-recommended substitute for the obsolete 0255004.M. Selection of the 0251004.MXL is supported by:

• Identical electrical ratings and breaking capacity, ensuring circuit protection equivalence
• Active product status with established supply chain availability
• Enhanced regulatory compliance including CCC, cURus, PSE, and TUV certifications in addition to CSA and UL
• ROHS3 compliance, meeting current environmental standards
• Defined operating temperature range of -55°C to 125°C
• Axial package compatibility with through-hole mounting

The dimensional difference (0.110" diameter versus 0.095" diameter) requires PCB layout verification to confirm mechanical fit within the original mounting footprint.

Frequently Asked Questions (FAQ)

Q: Can the 0251004.MXL be used as a direct replacement for the 0255004.M?

A: Yes. Both components share identical current ratings (4A), voltage ratings (125VAC/VDC), response time (Fast Blow), mounting type (Through Hole), and breaking capacity (50A AC, 300A DC). The 0251004.MXL is the manufacturer-recommended substitute.

Q: What is the significance of the dimensional difference between these parts?

A: The 0251004.MXL has a larger diameter (0.110" versus 0.095"). While the axial length remains identical at 0.280", the increased diameter requires verification that the component will fit within the original PCB mounting holes and surrounding circuit layout.

Q: Does the RoHS compliance difference affect substitution?

A: The 0251004.MXL is ROHS3 compliant, while the 0255004.M is RoHS non-compliant. For applications subject to RoHS regulations, the 0251004.MXL provides compliance. For legacy systems without RoHS requirements, both parts meet the electrical protection function.

Q: Are the approval certifications equivalent?

A: The 0251004.MXL carries expanded certifications (CCC, CSA, cURus, PSE, TUV) compared to the 0255004.M (CSA, UL). This broader certification scope supports use in additional regulatory jurisdictions and markets.

Q: What is the Melting I²t value and why is it provided only for the substitute?

A: The Melting I²t value of 2.45 for the 0251004.MXL characterizes the thermal energy required to melt the fuse element. This parameter is provided for the active product but not specified for the obsolete part. Both components maintain identical fast-blow response characteristics.