Littelfuse 0RLS250.X Fuse Cartridge - Equivalent & Substitute Parts

Part Overview

The Littelfuse 0RLS250.X is a 250A, 600VAC cylindrical fuse cartridge from the POWR-GARD® RLS series, designed for electrical and industrial applications requiring fast-blow protection. This part is classified as obsolete, making identification of suitable substitute components essential for system maintenance and replacement scenarios. The 0RLS250.X requires a dedicated fuse holder for installation and is rated for 10kA breaking capacity at its rated voltage.

Substiute Parts

0RLS250.X

Littelfuse Inc.In Stock: 12440RLS250.X Datasheet

Current PartRFQ

KLSR250.X

Littelfuse Inc.In Stock: 992KLSR250.X Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 0RLS250.X is determined by the following critical parameters that must remain constant or be compatible:

• Current Rating: 250A (exact match required)
• Voltage Rating - AC: 600 VAC (minimum requirement)
• Fuse Type: Cartridge (form factor requirement)
• Mounting Type: Requires Holder (mechanical compatibility)
• Package / Case: Cylindrical, Blade Terminals (physical interface requirement)
• Response Time: Fast Blow (protection characteristic)

The KLSR250.X from Littelfuse Inc. meets these core substitution criteria. While the KLSR250.X introduces additional capabilities (300 VDC rating, RK1 class, higher breaking capacity), these enhancements do not compromise compatibility with systems designed for the 0RLS250.X and represent an upgrade path for obsolete component replacement.

Parameter Comparison

Engineering Selection Recommendations

The KLSR250.X is the manufacturer-recommended substitute for the obsolete 0RLS250.X. Both components maintain identical current and AC voltage ratings, ensuring direct functional compatibility in 250A, 600VAC applications. The KLSR250.X is an active product with current manufacturing support, eliminating supply chain risk associated with the obsolete 0RLS250.X.

The KLSR250.X carries ROHS3 compliance and holds equivalent CE, CSA, and UL certifications as the original part. The increased breaking capacity (200kA AC versus 10kA) and RK1 class rating provide enhanced protection characteristics without compromising backward compatibility. The addition of 300 VDC rating capability expands application flexibility for mixed AC/DC systems.

Physical dimensions differ between the two parts (0RLS250.X: 2.594" Dia x 7.878" L; KLSR250.X: 2.594" Dia x 11.626" L). Verification of fuse holder clearance is required before installation to ensure the longer KLSR250.X cartridge fits within the available space.

Frequently Asked Questions (FAQ)

Q: Can the KLSR250.X directly replace the 0RLS250.X in existing installations?

A: The KLSR250.X is electrically and mechanically compatible for 250A, 600VAC applications. However, the KLSR250.X is 3.748 inches longer (11.626" L versus 7.878" L). Physical clearance within the fuse holder assembly must be verified before installation.

Q: What is the difference between Class H and Class RK1 fuses?

A: Both are fast-blow cartridge fuses rated for 250A at 600VAC. Class RK1 fuses provide higher breaking capacity (200kA AC) compared to Class H (10kA), offering enhanced protection in high-fault-current environments. The KLSR250.X RK1 classification represents an upgrade in protective capability.

Q: Why is the 0RLS250.X listed as obsolete?

A: The 0RLS250.X has been discontinued by Littelfuse Inc. The KLSR250.X serves as the active replacement, offering equivalent performance with improved compliance and breaking capacity ratings.

Q: Are both parts UL, CSA, and CE certified?

A: Yes. Both the 0RLS250.X and KLSR250.X hold UL, CSA, and CE approvals. The KLSR250.X additionally meets ROHS3 compliance requirements.

Q: What packaging is available for the KLSR250.X?

A: The KLSR250.X is supplied in box packaging. The 0RLS250.X packaging specification was not provided in the original documentation.

Q: Can the KLSR250.X be used in DC applications?

A: The KLSR250.X is rated for 300 VDC operation, enabling use in mixed AC/DC systems. The original 0RLS250.X DC rating was not specified.