Littelfuse 0RLS300.X Fuse Cartridge - Equivalent & Substitute Parts

Part Overview

The Littelfuse 0RLS300.X is a 300A, 600 VAC cylindrical fuse cartridge from the POWR-GARD® RLS series, designed for electrical and industrial applications requiring fast-blow response characteristics. This component is classified as obsolete, necessitating identification of active equivalent parts to maintain system functionality and ensure continued availability for replacement and new installations.

Substiute Parts

0RLS300.X

Littelfuse Inc.In Stock: 10940RLS300.X Datasheet

Current PartRFQ

KLSR300.X

Littelfuse Inc.In Stock: 1222KLSR300.X Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

The Littelfuse KLSR300.X serves as the manufacturer-recommended substitute for the 0RLS300.X. Substitution eligibility is determined by the following critical parameters:

Matching Parameters:

• Current Rating: 300A (identical)
• Voltage Rating - AC: 600 VAC (identical)
• Fuse Type: Cartridge (identical)
• Response Time: Fast Blow (identical)
• Mounting Type: Requires Holder (identical)
• Package / Case: Cylindrical, Blade Terminals (identical)
• Approval Agency: CE, CSA, UL (identical)

Enhanced Parameters in Substitute:

• Voltage Rating - DC: 300 VDC (additional capability)
• Class: RK1 (upgraded from Class H)
• Breaking Capacity @ Rated Voltage: 200kA AC, 20kA DC (upgraded from 10kA)
• Size / Dimension: 2.594" Dia x 11.626" L (increased length from 7.878")
• Product Status: Active (versus Obsolete)
• RoHS Compliance: ROHS3 Compliant (versus non-compliant)

Parameter Comparison

Engineering Selection Recommendations

The KLSR300.X is the direct manufacturer-recommended substitute for the obsolete 0RLS300.X. Both components maintain identical current and AC voltage ratings, fuse type, response characteristics, and mounting requirements. The KLSR300.X offers enhanced specifications including upgraded breaking capacity (200kA AC versus 10kA), RK1 class rating, DC voltage capability, and ROHS3 compliance status.

The primary consideration for implementation is the dimensional difference: the KLSR300.X has an increased length of 11.626" compared to the 0RLS300.X at 7.878". Verification that the fuse holder accommodates this increased length is required prior to installation. Both components carry identical regulatory approvals (CE, CSA, UL), ensuring compliance continuity.

Frequently Asked Questions (FAQ)

Q: Can the KLSR300.X directly replace the 0RLS300.X in existing installations?

A: The KLSR300.X is electrically and functionally equivalent for 300A, 600 VAC AC applications. However, the increased length (11.626" versus 7.878") requires confirmation that the existing fuse holder can accommodate the longer cartridge. Physical fit verification is mandatory before installation.

Q: What is the significance of the Class change from H to RK1?

A: Class H and Class RK1 are distinct fuse classifications with different breaking capacities and application profiles. The KLSR300.X's RK1 classification provides a breaking capacity of 200kA AC, substantially higher than the 0RLS300.X's 10kA rating. This upgrade enhances protection capability in high-fault-current environments.

Q: Does the KLSR300.X support DC applications?

A: Yes. The KLSR300.X is rated for 300 VDC in addition to 600 VAC, providing expanded application flexibility. The 0RLS300.X does not specify DC voltage capability.

Q: Are both fuses approved by the same regulatory agencies?

A: Yes. Both the 0RLS300.X and KLSR300.X carry CE, CSA, and UL approvals, ensuring regulatory compliance continuity.

Q: What is the impact of RoHS compliance differences?

A: The KLSR300.X is ROHS3 compliant, while the 0RLS300.X is non-compliant. For applications subject to RoHS regulations, the KLSR300.X meets current environmental and material restriction requirements.

Q: Are blade terminals identical between both fuses?

A: Both components feature cylindrical cartridges with blade terminals. Terminal compatibility depends on the specific fuse holder design. Verification with the holder manufacturer is recommended to ensure proper electrical contact and mechanical fit.