Littelfuse 03100326M Glass Cartridge Fuse 20A 32VAC/VDC Equivalent & Substitute Parts

Part Overview

The Littelfuse 03100326M is a 20A 32VAC/VDC glass cartridge fuse in 3AB/3AG form factor (0.250" Dia x 1.250" L). This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing system maintenance and new designs. The fuse requires a compatible holder for installation and is designed for general-purpose circuit protection applications requiring fast or slow-blow response characteristics.

Key Parameters

Parameter	Value
Current Rating	20 A
Voltage Rating (AC)	32 V
Voltage Rating (DC)	32 V
Fuse Type	Cartridge, Glass
Package / Case	3AB, 3AG, 1/4" x 1-1/4" (6.35mm x 31.75mm)
Mounting Type	Requires Holder
Product Status	Obsolete
RoHS Status	RoHS non-compliant

Substitute Part Grouping Explanation

Substitution for the 03100326M is determined by strict equivalence across the following parameters:

Current Rating: 20 A (exact match required)
Voltage Rating: 32 V AC and 32 V DC (exact match required)
Package / Case: 3AB, 3AG, 1/4" x 1-1/4" (exact match required)
Fuse Type: Cartridge, Glass (exact match required)
Mounting Type: Requires Holder (exact match required)

All substitute parts listed maintain these core electrical and mechanical specifications. Differences in response time (Fast Blow vs. Slow Blow), RoHS compliance status, and packaging configuration (Bulk vs. 5-pack card) do not affect functional interchangeability within the same circuit application, provided the circuit design accommodates the specific response characteristic.

Parameter Comparison

Part Number	Manufacturer	Current Rating (A)	Voltage AC (V)	Voltage DC (V)	Package / Case	Response Time	Product Status	RoHS Status
03100326M	Littelfuse	20	32	32	3AB, 3AG, 1/4" x 1-1/4"	—	Obsolete	RoHS non-compliant
0SFE020.V	Littelfuse Inc.	20	32	32	3AB, 3AG, 1/4" x 1-1/4"	Fast Blow	Active	ROHS3 Compliant
0307020.H	Littelfuse Inc.	20	32	32	3AB, 3AG, 1/4" x 1-1/4"	Fast Blow	Active	ROHS3 Compliant
0AGC020.V	Littelfuse	20	32	32	3AB, 3AG, 1/4" x 1-1/4"	—	Active	ROHS3 Compliant
0AGC020.VP	Littelfuse Inc.	20	32	32	3AB, 3AG, 1/4" x 1-1/4"	—	Active	ROHS3 Compliant
0SFE020.VP	Littelfuse Inc.	20	32	32	3AB, 3AG, 1/4" x 1-1/4"	—	Active	ROHS3 Compliant
MDL-20	Eaton - Electronics Division	20	32	32	3AB, 3AG, 1/4" x 1-1/4"	Slow Blow	Active	Not specified

Engineering Selection Recommendations

All listed substitute parts are electrically and mechanically equivalent to the 03100326M based on current rating, voltage rating, and physical form factor. Selection among substitutes should be based on the following criteria:

For RoHS3 Compliance Requirements: Parts 0SFE020.V, 0307020.H, 0AGC020.V, 0AGC020.VP, and 0SFE020.VP are ROHS3 compliant and are preferred for new designs or systems requiring regulatory compliance.

For Response Time Specification: If the circuit design requires Fast Blow response, select 0SFE020.V or 0307020.H. If Slow Blow response is required, select MDL-20 from Eaton. If response time is not specified in the original design, any substitute maintains functional equivalence.

For Packaging Configuration: Littelfuse parts are available in bulk packaging (0SFE020.V, 0307020.H, 0AGC020.V) or 5-pack card packaging (0AGC020.VP, 0SFE020.VP). Packaging selection does not affect electrical performance and is determined by procurement and inventory requirements.

For Certification Requirements: Part 0307020.H carries UL approval agency certification. MDL-20 carries CE certification. If specific approval agency certification is required by system design or regulatory standards, select accordingly.

Frequently Asked Questions (FAQ)

Q: Can I use any of these substitute parts interchangeably with the 03100326M?

A: Yes, all listed parts are electrically and mechanically equivalent. They share identical current ratings (20A), voltage ratings (32V AC/DC), and physical dimensions (3AB/3AG, 1/4" x 1-1/4"). Substitution is valid provided the circuit design accommodates the response time characteristic of the selected part.

Q: What is the difference between Fast Blow and Slow Blow response times?

A: Response time determines how quickly the fuse element melts under overcurrent conditions. Fast Blow fuses (0SFE020.V, 0307020.H) respond rapidly to transient overcurrents. Slow Blow fuses (MDL-20) tolerate brief overcurrent spikes before opening. Select based on the circuit's inrush current characteristics and protection requirements.

Q: Are the 5-pack card versions (0AGC020.VP, 0SFE020.VP) functionally identical to bulk versions?

A: Yes. Packaging configuration (bulk vs. 5-pack card) affects only procurement and storage. Electrical and mechanical specifications are identical. The fuse element and performance characteristics remain unchanged.

Q: Why is the original 03100326M marked as obsolete?

A: Obsolescence indicates the part is no longer manufactured. Active substitute parts from Littelfuse (0SFE020.V, 0307020.H, 0AGC020.V, 0AGC020.VP, 0SFE020.VP) provide direct functional replacement with improved compliance status (ROHS3 compliant).

Q: Does RoHS compliance affect fuse performance?

A: RoHS compliance relates to material composition and environmental standards, not electrical performance. ROHS3 compliant parts meet the same electrical specifications as the original part while adhering to hazardous substance restrictions.

Q: Can I substitute the Eaton MDL-20 for a Littelfuse part?

A: Yes, the MDL-20 is electrically and mechanically equivalent. However, it features Slow Blow response time, whereas most Littelfuse substitutes offer Fast Blow response. Verify that the circuit design accommodates Slow Blow characteristics before substitution.

Q: What holder types are compatible with these fuses?

A: All parts require a 3AB or 3AG fuse holder. Verify that existing holder hardware is rated for 20A at 32V AC/DC before installation.

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