Littelfuse 0RLS400.X Fuse Cartridge - Equivalent & Substitute Parts

Part Overview

The Littelfuse 0RLS400.X is a 400A, 600 VAC 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, necessitating identification of active equivalent components that maintain the same electrical and mechanical specifications for continued system operation and maintenance.

Substiute Parts

0RLS400.X

Littelfuse Inc.In Stock: 11790RLS400.X Datasheet

Current PartRFQ

KLSR400.X

Littelfuse Inc.In Stock: 1089KLSR400.X Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

The Littelfuse KLSR400.X qualifies as a substitute for the 0RLS400.X based on the following matching electrical and mechanical parameters:

• Current Rating: 400A (identical)
• Voltage Rating - AC: 600 VAC (identical)
• Fuse Type: Cartridge (identical)
• Response Time: Fast Blow (identical)
• Package / Case: Cylindrical, Blade Terminals (identical)
• Mounting Type: Requires Holder (identical)
• Approval Agencies: CE, CSA, UL (identical)

The KLSR400.X represents an active product with enhanced specifications, including dual voltage capability (600 VAC / 300 VDC), higher breaking capacity (200kA AC / 20kA DC), and RoHS3 compliance. The substitution is valid for 600 VAC applications where the original 0RLS400.X was specified.

Parameter Comparison

Engineering Selection Recommendations

The KLSR400.X is the recommended substitute for the obsolete 0RLS400.X in 600 VAC applications. Both components share identical current ratings, voltage specifications, fuse type, response characteristics, and approval certifications. The KLSR400.X offers the additional advantage of active product status, ensuring continued availability and supply chain reliability.

The KLSR400.X provides enhanced breaking capacity (200kA AC versus 10kA) and RoHS3 compliance, making it suitable for modern electrical systems with stricter environmental and performance requirements. The dimensional difference in length (11.626" versus 7.878") must be verified for compatibility with existing fuse holders and mounting hardware.

Frequently Asked Questions (FAQ)

Q: Can the KLSR400.X directly replace the 0RLS400.X in existing installations?

A: The KLSR400.X matches all critical electrical parameters (400A, 600 VAC, fast-blow response) and holds identical certifications. Physical compatibility depends on fuse holder dimensions. The KLSR400.X is longer (11.626" L versus 7.878" L), requiring verification that the existing holder accommodates this length.

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

A: Class designation is provided in the specifications. Both the 0RLS400.X (Class H) and KLSR400.X (Class RK1) are listed with their respective classifications. Selection between classes depends on system requirements and holder compatibility.

Q: Is the KLSR400.X suitable for DC applications?

A: The KLSR400.X is rated for 300 VDC, whereas the 0RLS400.X does not specify DC capability. If DC operation is required, the KLSR400.X provides this additional functionality. For AC-only applications at 600 VAC, both parts are equivalent.

Q: What is the significance of RoHS3 compliance on the KLSR400.X?

A: The KLSR400.X is RoHS3 compliant, while the 0RLS400.X is RoHS non-compliant. RoHS3 compliance indicates adherence to current environmental and material restriction standards, relevant for applications subject to regulatory requirements.

Q: Are there inventory considerations when selecting between these parts?

A: The 0RLS400.X (obsolete) has 1077 pcs in stock, while the KLSR400.X (active) has 1006 pcs in stock. For long-term supply assurance, the active KLSR400.X is the preferred choice despite current inventory levels.