Littelfuse 02291.25H Glass Cartridge Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 02291.25H is a 1.25 A, 250 V AC glass cartridge fuse in 2AG form factor (5mm x 15mm) with slow-blow response characteristics. This part is classified as obsolete. Equivalent and substitute parts are available from the same manufacturer series with active product status and enhanced compliance certifications, making them suitable for new designs and ongoing production requirements.

Key Parameters

Parameter	Value
Current Rating	1.25 A
Voltage Rating (AC)	250 V
Fuse Type	Cartridge, Glass
Package / Case	2AG, 5mm x 15mm
Response Time	Slow Blow
Mounting Type	Requires Holder
Melting I²t	9.8
Operating Temperature Range	-55°C to 125°C
Size / Dimension	0.177" Dia x 0.570" L (4.50mm x 14.48mm)

Substitute Part Grouping Explanation

Substitution of the 02291.25H is determined by the following critical parameters:

Current Rating: 1.25 A (exact match required)
Voltage Rating (AC): 250 V (exact match required)
Package / Case: 2AG, 5mm x 15mm (exact match required)
Response Time: Slow Blow (exact match required)
Melting I²t: 9.8 (exact match required)
Operating Temperature Range: -55°C to 125°C (exact match required)

All substitute parts listed below meet these core electrical and mechanical parameters. Differences exist in voltage rating (DC capability), breaking capacity, and compliance certifications, which are documented in the parameter comparison table.

Parameter Comparison

Parameter	02291.25H	02291.25HXP	02291.25HXSP	02291.25MXP	02291.25VXP	02291.25VXSP
Current Rating (Amps)	1.25 A	1.25 A	1.25 A	1.25 A	1.25 A	1.25 A
Voltage Rating - AC	250 V	250 V	250 V	250 V	250 V	250 V
Voltage Rating - DC	Not specified	125 V	125 V	125 V	125 V	125 V
Response Time	Slow Blow	Slow Blow	Slow Blow	Slow Blow	Slow Blow	Slow Blow
Package / Case	2AG, 5mm x 15mm	2AG, 5mm x 15mm	2AG, 5mm x 15mm	2AG, 5mm x 15mm	2AG, 5mm x 15mm	2AG, 5mm x 15mm
Breaking Capacity @ Rated Voltage	100A	35A AC, 10kA DC	35A AC, 10kA DC	35A AC, 10kA DC	100A AC, 10kA DC	100A AC, 10kA DC
Melting I²t	9.8	9.8	9.8	9.8	9.8	9.8
DC Cold Resistance (Ohms)	0.145	0.146	0.146	0.146	0.146	0.146
Operating Temperature	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C
Product Status	Obsolete	Active	Active	Active	Active	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Approval Agency	CSA, METI, UL	CE, CSA, PSE, UL	CE, CSA, PSE, UL	CE, CSA, PSE, UL	CE, CSA, PSE, UL	CE, CSA, PSE, UL

Engineering Selection Recommendations

All substitute parts maintain identical electrical performance for AC applications at 1.25 A and 250 V. Selection among substitute options depends on application-specific requirements:

For AC-only applications: Parts 02291.25HXP, 02291.25HXSP, 02291.25MXP, 02291.25VXP, and 02291.25VXSP are functionally equivalent to the 02291.25H.

For applications requiring DC voltage capability: All substitute parts provide 125 V DC rating, which the original 02291.25H does not specify.

For breaking capacity requirements: Parts 02291.25VXP and 02291.25VXSP provide 100A AC breaking capacity, matching the original part. Parts 02291.25HXP, 02291.25HXSP, and 02291.25MXP provide 35A AC breaking capacity.

For compliance-driven designs: All substitute parts carry ROHS3 compliance and expanded approval certifications (CE, CSA, PSE, UL) compared to the obsolete original part (CSA, METI, UL). The original part is RoHS non-compliant.

For new production and long-term availability: All substitute parts have active product status with current inventory levels, whereas the 02291.25H is obsolete.

Frequently Asked Questions (FAQ)

Q: Can I directly replace 02291.25H with any of the listed substitute parts?

A: Yes, for AC applications at 250 V and 1.25 A. All substitute parts share identical current rating, AC voltage rating, package form factor, response time, and thermal characteristics. Physical installation and electrical performance in AC circuits are equivalent.

Q: What is the difference between parts with 35A and 100A breaking capacity?

A: Breaking capacity defines the maximum fault current the fuse can safely interrupt without rupturing the fuse body. The 02291.25H and parts 02291.25VXP and 02291.25VXSP have 100A AC breaking capacity. Parts 02291.25HXP, 02291.25HXSP, and 02291.25MXP have 35A AC breaking capacity. Selection depends on the maximum prospective short-circuit current in your application.

Q: Does the DC voltage rating matter if my application is AC-only?

A: No. The DC voltage rating is not relevant for AC-only applications. All substitute parts are suitable for 250 V AC circuits regardless of their DC voltage specification.

Q: Why is the original 02291.25H obsolete?

A: The 02291.25H is classified as obsolete by the manufacturer. All substitute parts are active products with current production and inventory support, making them the recommended choice for new designs and ongoing production.

Q: Are there any compliance differences I should consider?

A: Yes. The 02291.25H is RoHS non-compliant. All substitute parts are ROHS3 compliant. Additionally, substitute parts carry CE and PSE certifications in addition to CSA and UL, providing broader regulatory coverage for international applications.

Q: Can I use these fuses in any 2AG fuse holder?

A: Yes. All parts listed, including the original 02291.25H and all substitutes, require a 2AG fuse holder. The 5mm x 15mm physical dimensions are identical across all parts, ensuring mechanical compatibility with any standard 2AG holder.

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