LR251003C Equivalent & Substitute Parts

Part Overview

The LR251003C is a Class R cartridge fuse holder rated for 100 A at 250V with 3 circuits, designed for chassis mount applications. This component is classified as obsolete, making identification of functionally equivalent alternatives essential for system maintenance, repair, and redesign projects. The part accepts Class R cartridge fuses and terminates via box lug connections.

Substiute Parts

LR251003C

Littelfuse Inc.In Stock: 1057LR251003C Datasheet

Current PartRFQ

LFR251003CID

Littelfuse Inc.In Stock: 861LFR251003CID Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

The LFR251003CID qualifies as a direct substitute based on the following critical parameters:

• Current Rating: 100 A (identical)
• Voltage Rating: 250V (identical)
• Number of Circuits: 3 (identical)
• Fuse Type: Cartridge (identical)
• Fuse Size: 1.063" Dia x 5.874" L / 27mm x 149.2mm (identical)
• Termination Style: Box Lug (identical)
• Fuse Compatibility: Class R Fuses (identical)
• Manufacturer: Littelfuse Inc. (same manufacturer)

The primary difference is the mounting configuration: LR251003C uses chassis mount, while LFR251003CID uses DIN rail mount. This distinction affects physical installation but does not alter electrical performance or fuse compatibility.

Parameter Comparison

Engineering Selection Recommendations

The LFR251003CID is electrically and mechanically compatible with the LR251003C for all fuse protection functions. Selection between these parts depends on installation requirements:

• Choose LFR251003CID when DIN rail mounting is available or can be accommodated in the system design. This part is active in production and meets ROHS3 compliance standards.
• The LR251003C remains suitable for existing chassis mount installations where the form factor is fixed, though availability is limited to existing inventory.

The transition from LR251003C to LFR251003CID represents a shift in mounting architecture rather than a change in electrical performance. Both parts accept identical Class R cartridge fuses and maintain the same current and voltage ratings.

Frequently Asked Questions (FAQ)

Q: Can LFR251003CID replace LR251003C in an existing system?

A: Electrically, yes. The LFR251003CID accepts the same Class R cartridge fuses and operates at identical current and voltage ratings. However, physical installation differs: LR251003C requires chassis mount hardware, while LFR251003CID requires DIN rail mounting. Mechanical compatibility depends on your enclosure design.

Q: What is the difference between a fuse holder and a fuse block?

A: Both terms describe devices that hold and protect cartridge fuses. The LR251003C is designated a holder with chassis mount configuration, while the LFR251003CID is designated a block with DIN rail configuration. Functionally, they serve the same purpose.

Q: Are the fuse cartridges interchangeable between these two parts?

A: Yes. Both parts accept Class R cartridge fuses of 1.063" diameter x 5.874" length (27mm x 149.2mm). Any Class R fuse rated for 250V and appropriate amperage will work in either holder.

Q: Why is LR251003C obsolete?

A: The LR251003C has been discontinued by Littelfuse Inc. The LFR251003CID represents the current production equivalent with updated DIN rail mounting and improved compliance standards.

Q: Does RoHS compliance affect electrical performance?

A: No. RoHS compliance relates to material composition and environmental standards, not electrical function. Both parts perform identically in circuit protection applications.