Littelfuse 0312020.H Glass Cartridge Fuse 20A 32VAC Equivalent & Substitute Parts

Part Overview

The Littelfuse 0312020.H is a 20 A, 32 V AC/DC glass cartridge fuse with fast-blow response characteristics, designed for 3AB and 3AG holder compatibility. This part operates across a temperature range of -55°C to 125°C and features a compact 1/4" × 1-1/4" form factor. The product is currently obsolete, making identification of functionally equivalent alternatives essential for system maintenance and component replacement in existing installations.

Key Parameters

Parameter	Value
Current Rating	20 A
Voltage Rating (AC)	32 V
Fuse Type	Cartridge, Glass
Response Time	Fast Blow
Package / Case	3AB, 3AG, 1/4" × 1-1/4"
Mounting Type	Requires Holder
Operating Temperature Range	-55°C to 125°C
Size / Dimension	0.250" Dia × 1.250" L (6.35mm × 31.75mm)

Substitute Part Grouping Explanation

Substitution eligibility for the 0312020.H is determined by strict equivalence across the following parameters:

Current Rating: 20 A (exact match required)
Voltage Rating (AC): 32 V (exact match required)
Fuse Type: Cartridge, Glass (exact match required)
Response Time: Fast Blow (exact match required)
Package / Case: 3AB, 3AG, 1/4" × 1-1/4" (exact match required)
Mounting Type: Requires Holder (exact match required)
Operating Temperature Range: -55°C to 125°C (minimum requirement)

All substitute parts listed below meet these criteria and are mechanically and electrically interchangeable with the original part number.

Parameter Comparison

Part Number	Manufacturer	Current Rating	Voltage Rating (AC)	Response Time	Package / Case	Operating Temperature	DC Cold Resistance	Product Status	RoHS Status
0312020.H	Littelfuse Inc.	20 A	32 V	Fast Blow	3AB, 3AG, 1/4" × 1-1/4"	-55°C to 125°C	0.0034 Ω	Obsolete	RoHS Non-Compliant
0312020.MXP	Littelfuse Inc.	20 A	32 V	Fast Blow	3AB, 3AG, 1/4" × 1-1/4"	-55°C to 125°C	0.0035 Ω	Active	ROHS3 Compliant
0312020.HXP	Littelfuse Inc.	20 A	32 V	Fast Blow	3AB, 3AG, 1/4" × 1-1/4"	-55°C to 125°C	0.0035 Ω	Active	ROHS3 Compliant
0312020.VXP	Littelfuse Inc.	20 A	32 V	Fast Blow	3AB, 3AG, 1/4" × 1-1/4"	-55°C to 125°C	0.0035 Ω	Active	ROHS3 Compliant
AGC-20-R	Eaton - Electronics Division	20 A	32 V	Fast Blow	3AB, 3AG, 1/4" × 1-1/4"	-55°C to 125°C	0.0034 Ω	Active	RoHS Compliant
BK/AGC-20-R	Eaton - Electronics Division	20 A	32 V	Fast Blow	3AB, 3AG, 1/4" × 1-1/4"	-55°C to 125°C	0.0034 Ω	Active	ROHS3 Compliant

Engineering Selection Recommendations

For replacement of the obsolete 0312020.H, the following selection criteria apply:

Littelfuse Series 312 Alternatives (0312020.MXP, 0312020.HXP, 0312020.VXP): These parts maintain manufacturer continuity and are direct successors within the same product line. All three are active products with ROHS3 compliance and cULus or UL certification. These options are preferred when maintaining original manufacturer specifications is a requirement.

Eaton AGC Series Alternatives (AGC-20-R, BK/AGC-20-R): These cross-manufacturer substitutes provide equivalent electrical and mechanical performance. Both are active products with full RoHS compliance and UL/CSA certification. The AGC series represents an alternative manufacturer solution with established market availability.

Product status and compliance certifications are the primary differentiators. All listed substitutes are active products, whereas the original 0312020.H is obsolete. Selection between Littelfuse and Eaton alternatives depends on existing supply chain relationships and procurement preferences.

Frequently Asked Questions (FAQ)

Q: Can the 0312020.H be directly replaced with any of the listed substitutes?

A: Yes. All listed substitute parts are mechanically and electrically interchangeable. They share identical current ratings (20 A), voltage ratings (32 V AC), response characteristics (fast blow), physical dimensions (1/4" × 1-1/4"), and holder compatibility (3AB, 3AG).

Q: What is the difference between the Littelfuse 312 series variants (0312020.MXP, 0312020.HXP, 0312020.VXP)?

A: These three part numbers are functionally equivalent within the Littelfuse 312 series. Differences are limited to packaging designations and internal manufacturing specifications. All three meet identical electrical and mechanical requirements for the 0312020.H application.

Q: Are there differences between Littelfuse and Eaton alternatives?

A: Both manufacturers' products meet the same electrical specifications and holder compatibility requirements. Differences exist in breaking capacity ratings (Littelfuse 312 series: 300 A; Eaton AGC series: 1 kA) and melting I²t values, but these do not affect interchangeability for the specified 20 A, 32 V application. Selection depends on procurement availability and supply chain preference.

Q: Does RoHS compliance status affect substitution eligibility?

A: RoHS compliance does not affect electrical or mechanical interchangeability. The original 0312020.H is RoHS non-compliant, while all active substitutes are RoHS3 compliant. For new designs or systems with RoHS requirements, the compliant alternatives are appropriate. For legacy system maintenance, non-compliance status does not impact functional performance.

Q: Are all substitutes approved by the same certification agencies?

A: All substitutes carry CSA and UL certifications, matching or exceeding the original part's approval status. Littelfuse 312 series parts carry cULus certification in addition to CSA/UL. Eaton AGC series parts carry standard UL/CSA certification. All certifications are valid for the specified application parameters.

Q: What is the significance of the DC cold resistance values?

A: DC cold resistance values (0.0034 Ω to 0.0035 Ω) are within normal manufacturing tolerance ranges and do not affect substitution eligibility. These minor variations are typical across different manufacturing batches and do not impact circuit performance in the specified 20 A, 32 V application.

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