FNW-25 Equivalent & Substitute Parts Reference

Part Overview

The FNW-25 is a 25A 250VAC cartridge fuse manufactured by Eaton - Bussmann Electrical Division, classified as a 5AG (10mm x 38mm Midget) slow-blow fuse cartridge requiring a holder for installation. The part is currently obsolete, necessitating identification of equivalent and substitute components that maintain the same electrical and mechanical specifications for continued system operation and maintenance.

Substiute Parts

FNW-25

Eaton - Bussmann Electrical DivisionIn Stock: 1169FNW-25 Datasheet

Current PartRFQ

FNM-25

Eaton - Bussmann Electrical DivisionIn Stock: 961FNM-25 Datasheet

DirectRFQ

0FLM025.T

Littelfuse Inc.In Stock: 12310FLM025.T Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the FNW-25 is determined by strict equivalence across the following critical parameters: current rating (25A), AC voltage rating (250 VAC), fuse type (cartridge), response time (slow blow), package classification (5AG), physical dimensions (10mm x 38mm), and breaking capacity (10kA). All identified substitutes maintain these specifications, ensuring direct functional and mechanical compatibility within existing fuse holder assemblies.

The FNW-25 has two identified substitutes: FNM-25 (Eaton - Bussmann Electrical Division, direct manufacturer equivalent) and 0FLM025.T (Littelfuse Inc., cross-manufacturer equivalent). Both parts satisfy all critical electrical and mechanical parameters required for substitution.

Parameter Comparison

Engineering Selection Recommendations

FNM-25 is the primary substitute, being a direct equivalent from the same manufacturer (Eaton - Bussmann Electrical Division) with identical electrical specifications, active product status, and equivalent regulatory approvals (CE, CSA, UL). This part maintains full compatibility with existing FNW-25 installations.

0FLM025.T is a secondary substitute from Littelfuse Inc., meeting all critical AC voltage and current specifications. This part provides additional DC voltage capability (125 VDC) not present in the FNW-25 specification, and maintains active product status with regulatory approvals (CSA, PSE, QPL, UL). Physical dimensions are within tolerance of the FNW-25, ensuring mechanical compatibility in standard 5AG fuse holders.

Both substitutes are suitable for direct replacement based on provided electrical and mechanical parameters. Selection between FNM-25 and 0FLM025.T depends on supply chain availability and specific application requirements.

Frequently Asked Questions (FAQ)

Q: Can FNM-25 directly replace FNW-25 in existing installations? A: Yes. FNM-25 maintains identical current rating (25A), AC voltage rating (250 VAC), fuse type (cartridge), response time (slow blow), package classification (5AG), physical dimensions (10mm x 38mm), and breaking capacity (10kA). Both require a fuse holder for installation.

Q: What is the difference between FNW-25 and FNM-25? A: Both are 25A 250VAC 5AG cartridge fuses from Eaton - Bussmann. The primary difference is product status: FNW-25 is obsolete while FNM-25 is active. Electrical and mechanical specifications are equivalent.

Q: Can 0FLM025.T replace FNW-25? A: Yes. 0FLM025.T meets all critical specifications: 25A current rating, 250 VAC AC voltage rating, cartridge type, slow-blow response, 5AG package, 10mm x 38mm dimensions, and 10kA breaking capacity. The part additionally supports 125 VDC operation, which does not affect AC-only applications.

Q: Are there dimensional compatibility concerns with substitute parts? A: No. All substitute parts use the 5AG (10mm x 38mm Midget) package classification with dimensions within tolerance: FNW-25 (10.30mm x 38.00mm), FNM-25 (10.30mm x 38.10mm), and 0FLM025.T (10.31mm x 38.10mm). All are compatible with standard 5AG fuse holders.

Q: Which regulatory approvals apply to substitute parts? A: FNM-25 carries CE, CSA, and UL approvals. 0FLM025.T carries CSA, PSE, QPL, and UL approvals. Both meet the regulatory framework of the obsolete FNW-25 (CE, CSA, UL).

Q: What is the breaking capacity specification? A: All parts (FNW-25, FNM-25, 0FLM025.T) have a breaking capacity of 10kA at rated voltage, indicating the maximum fault current the fuse can safely interrupt.