Littelfuse 031303.2HXP Equivalent & Substitute Parts

Part Overview

The Littelfuse 031303.2HXP is a 3.2 A, 250 V AC/DC slow-blow glass cartridge fuse designed for 3AB and 3AG holder applications. This fuse is classified as Active product status and is widely used in industrial and commercial electrical protection circuits. Identifying equivalent and substitute parts is necessary when managing inventory, addressing supply chain constraints, or selecting functionally compatible alternatives that meet identical electrical and mechanical specifications.

Key Parameters

Parameter	Value
Current Rating	3.2 A
Voltage Rating (AC)	250 V
Response Time	Slow Blow
Fuse Type	Cartridge, Glass
Package / Case	3AB, 3AG, 1/4" x 1-1/4"
Breaking Capacity @ Rated Voltage	100 A
Operating Temperature Range	-55°C ~ 125°C
Size / Dimension	0.250" Dia x 1.250" L (6.35mm x 31.75mm)
DC Cold Resistance	0.0529 Ohms
RoHS Status	ROHS3 Compliant
Approval Agencies	CE, CSA, K-MARK, PSE, UL

Substitute Part Grouping Explanation

Substitute parts for the 031303.2HXP are determined by strict equivalence across the following critical parameters:

Current Rating: 3.2 A (exact match required)
Voltage Rating: 250 V AC (exact match required)
Response Time: Slow Blow (exact match required)
Fuse Type: Cartridge, Glass (exact match required)
Package / Case: 3AB, 3AG, 1/4" x 1-1/4" (exact match required)
Breaking Capacity: 100 A (exact match required)
Operating Temperature Range: -55°C ~ 125°C (exact match required)
Physical Dimensions: 0.250" Dia x 1.250" L (exact match required)

Parts meeting all these criteria are considered direct electrical and mechanical equivalents. Variations in manufacturer, series designation, or secondary parameters such as Melting I²t do not disqualify a part from substitution when all primary electrical and mechanical specifications align.

Parameter Comparison

Parameter	031303.2HXP (Littelfuse)	031303.2MXP (Littelfuse)	0034.5237 (SCHURTER)
Current Rating (Amps)	3.2 A	3.2 A	3.2 A
Voltage Rating - AC	250 V	250 V	250 V
Response Time	Slow Blow	Slow Blow	Slow Blow
Fuse Type	Cartridge, Glass	Cartridge, Glass	Cartridge, Glass
Package / Case	3AB, 3AG, 1/4" x 1-1/4"	3AB, 3AG, 1/4" x 1-1/4"	3AB, 3AG, 1/4" x 1-1/4"
Breaking Capacity @ Rated Voltage	100 A	100 A	100 A
Operating Temperature	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C
Size / Dimension	0.250" Dia x 1.250" L (6.35mm x 31.75mm)	0.250" Dia x 1.250" L (6.35mm x 31.75mm)	0.250" Dia x 1.250" L (6.35mm x 31.75mm)
DC Cold Resistance	0.0529 Ohms	0.0529 Ohms	Not specified
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Product Status	Active	Active	Obsolete
Approval Agencies	CE, CSA, K-MARK, PSE, UL	CE, CSA, K-MARK, PSE, UL	CSA, UL

Engineering Selection Recommendations

The Littelfuse 031303.2MXP is a direct equivalent to the 031303.2HXP. Both parts share identical electrical specifications, mechanical dimensions, and approval certifications. The 031303.2MXP maintains Active product status and is suitable for direct substitution in all applications where the 031303.2HXP is specified.

The SCHURTER 0034.5237 meets all critical electrical and mechanical parameters and is functionally equivalent. However, this part carries Obsolete product status and holds fewer approval certifications (CSA, UL) compared to the Littelfuse alternatives (CE, CSA, K-MARK, PSE, UL). Selection of the SCHURTER part should be limited to legacy system maintenance or applications where only CSA and UL certifications are required.

For new designs and standard applications, the Littelfuse 031303.2MXP is the preferred substitute due to Active product status and comprehensive regulatory approvals.

Frequently Asked Questions (FAQ)

Q: Can the 031303.2MXP be used as a direct replacement for the 031303.2HXP?

A: Yes. Both parts are manufactured by Littelfuse, share identical current ratings (3.2 A), voltage ratings (250 V AC), response characteristics (Slow Blow), physical dimensions (0.250" Dia x 1.250" L), and approval certifications. They are electrically and mechanically interchangeable.

Q: Is the SCHURTER 0034.5237 a suitable substitute?

A: The SCHURTER 0034.5237 meets all critical electrical and mechanical specifications. However, it carries Obsolete product status and holds fewer regulatory approvals (CSA, UL only versus CE, CSA, K-MARK, PSE, UL). Use this part only when legacy compatibility is required or when application certifications are limited to CSA and UL.

Q: What determines whether a fuse can substitute for the 031303.2HXP?

A: Substitution requires exact matching of current rating (3.2 A), voltage rating (250 V AC), response time (Slow Blow), fuse type (Cartridge, Glass), package designation (3AB, 3AG), breaking capacity (100 A), and physical dimensions (0.250" Dia x 1.250" L). Manufacturer differences do not prevent substitution when these parameters align.

Q: Are there differences in melting I²t values between these parts?

A: Yes. The 031303.2HXP and 031303.2MXP both specify 209 Melting I²t, while the SCHURTER 0034.5237 specifies 136 Melting I²t. Despite this difference, all three parts maintain identical response time classification (Slow Blow) and meet the same electrical protection requirements for 3.2 A circuits.

Q: Which part should be selected for new equipment designs?

A: The Littelfuse 031303.2MXP is recommended for new designs. It maintains Active product status, carries comprehensive regulatory approvals (CE, CSA, K-MARK, PSE, UL), and ensures long-term supply chain availability.

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