Littelfuse 0673003.DRT4P Equivalent & Substitute Parts

Part Overview

The Littelfuse 0673003.DRT4P is a 3 A, 250 V AC/DC glass cartridge fuse with axial through-hole mounting. This component is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing maintenance applications. The slow-blow response characteristic and 50 A breaking capacity at rated voltage define its operational profile in circuit protection applications.

Substiute Parts

0673003.DRT4P

Littelfuse Inc.In Stock: 11030673003.DRT4P Datasheet

Current PartRFQ

0875003.MRET1P

Littelfuse Inc.In Stock: 11550875003.MRET1P Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

The Littelfuse 0875003.MRET1P qualifies as a direct substitute based on the following matched electrical parameters:

• Current Rating: 3 A (identical)
• Voltage Rating (AC): 250 V (identical)
• Response Time: Slow Blow (identical)
• Mounting Type: Through Hole (identical)
• Breaking Capacity @ Rated Voltage: 50 A (identical)
• Approval Agency: cULus certification (equivalent to CSA/UL)
• RoHS Status: ROHS3 Compliant (identical)

The primary difference is the fuse element material: the substitute uses ceramic construction instead of glass. Both cartridge types are non-standard axial configurations. The substitute part is currently active in production, addressing the obsolescence status of the original component.

Parameter Comparison

Engineering Selection Recommendations

The 0875003.MRET1P is the appropriate substitute for the obsolete 0673003.DRT4P based on electrical equivalence and regulatory compliance. Both components meet the same current and voltage specifications with identical breaking capacity and response characteristics. The substitute part carries active production status and cULus certification, ensuring continued availability and regulatory acceptance.

The ceramic construction of the substitute provides a higher melting I²t value (24.5 versus 18.4), indicating enhanced thermal capacity. The substitute's defined operating temperature range (-55°C ~ 125°C) provides explicit thermal boundaries absent from the original specification. Physical dimensions differ slightly, with the substitute measuring 0.142" Dia x 0.394" L compared to the original 0.154" Dia x 0.433" L; mechanical fit verification in the target application is necessary.

Frequently Asked Questions (FAQ)

Q: Can the 0875003.MRET1P directly replace the 0673003.DRT4P in existing designs?

A: Electrical substitution is valid based on matched current rating, voltage rating, response time, and breaking capacity. Physical dimensions differ slightly; mechanical fit in the existing fuse holder must be confirmed before implementation.

Q: What is the significance of the ceramic versus glass construction?

A: Both materials function as fuse elements in cartridge form. The ceramic construction of the substitute exhibits a higher melting I²t value, affecting thermal response characteristics. The choice between materials depends on application-specific thermal and mechanical requirements.

Q: Are the certifications equivalent?

A: The original part carries CSA and UL approvals. The substitute carries cULus certification, which represents combined UL and CSA recognition. This certification is equivalent for North American regulatory compliance.

Q: What is the impact of the dimensional difference?

A: The substitute is slightly smaller (0.142" Dia x 0.394" L versus 0.154" Dia x 0.433" L). Mechanical compatibility with the fuse holder must be verified, as dimensional tolerance and holder design determine whether the smaller cartridge will function reliably in the existing socket.

Q: Why does the substitute have a specified operating temperature range while the original does not?

A: The original specification does not include an operating temperature range. The substitute explicitly defines -55°C ~ 125°C operation, providing design guidance for thermal applications. This does not indicate incompatibility; it reflects more complete specification documentation.

Q: What does the higher melting I²t value mean for circuit protection?

A: The substitute's melting I²t of 24.5 versus the original's 18.4 indicates greater thermal energy absorption before element fusion. This affects the fuse's response to transient overcurrent conditions and should be evaluated against application-specific protection requirements.