FWA-400ASI4 Equivalent & Substitute Parts

Part Overview

The FWA-400ASI4 is a 400A cartridge fuse manufactured by Eaton - Bussmann Electrical Division, rated for 150 VAC and 150 VDC operation. This component is designed for bolt mount installation in electrical and industrial applications requiring high-current protection with fast-acting response characteristics. The part maintains Active product status with 851 units in current inventory. Substitute parts are identified when equivalent electrical ratings, mechanical compatibility, and approval certifications align with the original specification, enabling component interchangeability in system designs.

Substiute Parts

FWA-400ASI4

Eaton - Bussmann Electrical DivisionIn Stock: 938FWA-400ASI4 Datasheet

Current PartRFQ

L15S400.T

Littelfuse Inc.In Stock: 1065L15S400.T Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the FWA-400ASI4 is determined by strict alignment of the following electrical and mechanical parameters:

Critical Matching Parameters:

• Current Rating: 400A (exact match required)
• Voltage Rating - AC: 150 VAC (exact match required)
• Fuse Type: Cartridge (exact match required)
• Mounting Type: Bolt Mount (exact match required)
• Package / Case: Cylindrical, Blade Terminal (Bolt) (exact match required)
• Physical Dimensions: 1.000" Dia x 1.156" L ±0.001" (exact match required)
• Breaking Capacity @ Rated Voltage: 100kA AC, 20kA DC (exact match required)

Allowable Variation Parameters:

• Voltage Rating - DC: May vary within system design constraints
• Response Time: May vary based on application requirements
• Manufacturer: Different manufacturer acceptable if all other parameters match
• Approval Agency: Acceptable if includes CE and/or UR certification
• RoHS Compliance Status: Acceptable if meets or exceeds original specification

The L15S400.T from Littelfuse Inc. qualifies as a substitute based on matching current rating, AC voltage rating, fuse type, mounting configuration, physical dimensions, and breaking capacity. The DC voltage rating differential (100 VDC vs. 150 VDC) represents a reduced capability that must be evaluated within specific circuit requirements.

Parameter Comparison

Engineering Selection Recommendations

Both the FWA-400ASI4 and L15S400.T maintain Active product status with current manufacturing support and inventory availability. Selection between these components should be based on the following engineering criteria:

FWA-400ASI4 (Eaton - Bussmann): Select this component when the circuit design requires 150 VDC rated protection or when Eaton component standardization is specified in system documentation. This part carries CE and UR approvals with RoHS compliance.

L15S400.T (Littelfuse): Select this component when the circuit operates at or below 100 VDC, when Littelfuse component standardization is preferred, or when CSA certification is required in addition to CE and UR. This part carries CE, CSA, and UR approvals with ROHS3 compliance and is identified as Fast Blow response type.

Both components share identical current ratings, AC voltage ratings, mechanical mounting configurations, physical dimensions, and breaking capacities. The primary differentiation factor is the DC voltage rating specification and response time classification.

Frequently Asked Questions (FAQ)

Q: Can the L15S400.T replace the FWA-400ASI4 in all applications?

A: The L15S400.T is mechanically and electrically compatible for applications operating at or below 100 VDC. If the circuit design requires 150 VDC protection capability, the FWA-400ASI4 must be retained. Verify the actual DC voltage present in the circuit before substitution.

Q: Are the physical dimensions identical between these two fuses?

A: The dimensions are functionally equivalent. Both measure 1.000" diameter with lengths of 1.156" (FWA-400ASI4) and 1.157" (L15S400.T), representing a 0.001" variation within standard manufacturing tolerance. Both fit identical bolt mount receptacles.

Q: What is the significance of the "Fast Blow" designation on the L15S400.T?

A: Fast Blow indicates the fuse responds quickly to overcurrent conditions. The FWA-400ASI4 does not specify response time in the provided data. Confirm that Fast Blow response characteristics are compatible with the protected circuit before substitution.

Q: Do both fuses carry the same regulatory approvals?

A: Both fuses carry CE and UR approvals. The L15S400.T additionally carries CSA certification. Both meet RoHS compliance requirements (RoHS Compliant and ROHS3 Compliant respectively).

Q: What does the melting I²t value of 20300 indicate?

A: The melting I²t value represents the thermal energy required to melt the fuse element. This value is provided only for the FWA-400ASI4 in the available data and is a critical parameter for circuit protection coordination. Verify this specification when substituting components in coordinated protection systems.

Q: Can these fuses be used interchangeably in existing inventory systems?

A: Both components are currently in stock with Active product status. Interchangeability depends on circuit voltage requirements and any system-level component standardization specifications. Maintain separate inventory tracking for each manufacturer part number to ensure correct component selection during assembly and maintenance operations.