Littelfuse 0230004.DRT2SW Glass Axial Fuse 4A 125VAC Equivalent & Substitute Parts

Part Overview

The Littelfuse 0230004.DRT2SW is a 4A 125VAC slow-blow glass cartridge fuse with axial through-hole mounting. This component is classified as obsolete, making equivalent substitute parts necessary for ongoing design support and production continuity. The fuse is rated for 125V AC/DC operation with a 400A breaking capacity and operates across the temperature range of -55°C to 125°C. Substitute parts maintain identical electrical and mechanical specifications while offering active product status and improved compliance certifications.

Key Parameters

Parameter	Value
Current Rating	4 A
Voltage Rating (AC)	125 V
Fuse Type	Cartridge, Glass
Response Time	Slow Blow
Package / Case	Cartridge, Non-Standard (Axial)
Mounting Type	Through Hole
Size / Dimension	0.177" Dia x 0.571" L (4.50mm x 14.50mm)
Breaking Capacity @ Rated Voltage	400A
Melting I²t	148
DC Cold Resistance	0.0256 Ohms
Operating Temperature Range	-55°C ~ 125°C

Substitute Part Grouping Explanation

Substitution of the 0230004.DRT2SW is determined by strict equivalence across the following critical parameters:

Current Rating: 4 A (exact match required)
Voltage Rating: 125 V AC minimum (125 V DC acceptable)
Fuse Type: Cartridge, Glass (exact match required)
Response Time: Slow Blow (exact match required)
Package / Case: Cartridge, Non-Standard (Axial) (exact match required)
Size / Dimension: 0.177" Dia x 0.571" L / 4.50mm x 14.50mm (exact match required)
Breaking Capacity: 400A (exact match required)
Melting I²t: 148 (exact match required)

All substitute parts listed maintain these specifications. Differences exist only in packaging format (Tape & Reel vs. Cut Tape) and product status (Active vs. Obsolete). The primary distinction between the main part and substitutes is RoHS compliance status and certification agency approvals.

Parameter Comparison

Part Number	Manufacturer	Current Rating	Voltage AC	Voltage DC	Response Time	Package	Packaging Format	Product Status	RoHS Status	Certifications	DC Cold Resistance	Inventory
0230004.DRT2SW	Littelfuse Inc.	4 A	125 V	—	Slow Blow	Cartridge, Non-Standard (Axial)	—	Obsolete	RoHS non-compliant	cUL, METI	0.0256 Ω	696 Pcs
0230004.DRT2SP	Littelfuse	4 A	125 V	125 V	Slow Blow	Cartridge, Non-Standard (Axial)	Tape & Reel (TR)	Active	ROHS3 Compliant	CE, CSA, PSE, UL	0.0258 Ω	1175 Pcs
0230004.DRT1P	Littelfuse Inc.	4 A	125 V	125 V	Slow Blow	Cartridge, Non-Standard (Axial)	Cut Tape (CT)	Active	ROHS3 Compliant	CE, CSA, PSE, UL	0.0258 Ω	6952 Pcs
0230004.DRT1SP	Littelfuse Inc.	4 A	125 V	125 V	Slow Blow	Cartridge, Non-Standard (Axial)	Tape & Reel (TR)	Active	ROHS3 Compliant	CE, CSA, PSE, UL	0.0258 Ω	811 Pcs
0230004.DRT2P	Littelfuse Inc.	4 A	125 V	125 V	Slow Blow	Cartridge, Non-Standard (Axial)	Tape & Reel (TR)	Active	ROHS3 Compliant	CE, CSA, PSE, UL	0.0258 Ω	979 Pcs
0230004.DRT3P	Littelfuse Inc.	4 A	125 V	125 V	Slow Blow	Cartridge, Non-Standard (Axial)	Tape & Reel (TR)	Active	ROHS3 Compliant	CE, CSA, PSE, UL	0.0258 Ω	984 Pcs
0230004.DRT3SP	Littelfuse Inc.	4 A	125 V	125 V	Slow Blow	Cartridge, Non-Standard (Axial)	Tape & Reel (TR)	Active	ROHS3 Compliant	CE, CSA, PSE, UL	0.0258 Ω	1039 Pcs
0230004.MRT1SSP	Littelfuse Inc.	4 A	125 V	125 V	Slow Blow	Cartridge, Non-Standard (Axial)	Tape & Reel (TR)	Active	ROHS3 Compliant	CE, CSA, PSE, UL	0.0258 Ω	1036 Pcs

Engineering Selection Recommendations

All listed substitute parts are electrically and mechanically equivalent to the 0230004.DRT2SW. Selection between substitutes depends on packaging and compliance requirements:

For new designs and production requiring RoHS3 compliance and expanded certification coverage (CE, CSA, PSE, UL), any of the active-status parts are suitable. The 0230004.DRT1P offers the highest inventory availability (6952 Pcs) in Cut Tape format for manual assembly or low-volume applications. Tape & Reel packaged variants (0230004.DRT2SP, 0230004.DRT1SP, 0230004.DRT2P, 0230004.DRT3P, 0230004.DRT3SP, 0230004.MRT1SSP) are appropriate for automated pick-and-place assembly processes.

The original 0230004.DRT2SW is obsolete and non-RoHS compliant. Direct replacement with 0230004.DRT2SP maintains identical packaging format while providing active product status and improved certifications.

Frequently Asked Questions (FAQ)

Q: Can I use any of these substitute parts interchangeably with the 0230004.DRT2SW?

A: Yes. All listed parts are parametrically equivalent across current rating (4A), voltage rating (125V AC/DC), fuse type (cartridge glass), response time (slow blow), physical dimensions (0.177" Dia x 0.571" L), breaking capacity (400A), and melting I²t (148). Differences exist only in packaging format and product status.

Q: What is the difference between Cut Tape (CT) and Tape & Reel (TR) packaging?

A: Cut Tape packaging is supplied as individual components on carrier tape, suitable for manual assembly or low-volume production. Tape & Reel packaging is continuous reel format optimized for automated pick-and-place assembly equipment. Electrical and mechanical specifications are identical between formats.

Q: Why is the original part marked as obsolete?

A: The 0230004.DRT2SW is classified as obsolete by the manufacturer. All substitute parts listed maintain active product status, ensuring long-term availability and continued manufacturing support.

Q: Does RoHS3 compliance affect electrical performance?

A: No. RoHS3 compliance relates to material composition and environmental restrictions, not electrical characteristics. All substitute parts maintain identical electrical specifications including current rating, voltage rating, response time, and breaking capacity.

Q: Which substitute part should I select for new production?

A: For automated assembly, select a Tape & Reel variant (0230004.DRT2SP, 0230004.DRT1SP, 0230004.DRT2P, 0230004.DRT3P, 0230004.DRT3SP, or 0230004.MRT1SSP). For manual assembly or prototyping, select 0230004.DRT1P in Cut Tape format. All are RoHS3 compliant with active product status.

Q: Are the certification agencies different between the main part and substitutes?

A: Yes. The original 0230004.DRT2SW carries cUL and METI certifications. All substitute parts carry CE, CSA, PSE, and UL certifications, providing broader international compliance coverage.

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