Littelfuse 02391.25H Glass Cartridge Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 02391.25H is a 1.25 A, 250 V AC/DC slow-blow glass cartridge fuse in 5mm x 20mm form factor, designed for applications requiring overcurrent protection in industrial and consumer equipment. This part is classified as obsolete, necessitating identification of active equivalent alternatives that maintain electrical and mechanical compatibility while meeting current regulatory requirements.

Key Parameters

Parameter	Value
Current Rating	1.25 A
Voltage Rating (AC)	250 V
Response Time	Slow Blow
Package / Case	5mm x 20mm
Fuse Type	Cartridge, Glass
Mounting Type	Requires Holder
Operating Temperature Range	-55°C to 125°C
Breaking Capacity @ Rated Voltage	100 A

Substitute Part Grouping Explanation

Substitution of the 02391.25H is determined by strict equivalence across the following parameters:

Current Rating: 1.25 A (exact match required)
Voltage Rating: 250 V AC (exact match required)
Response Time: Slow Blow (exact match required)
Package / Case: 5mm x 20mm (exact match required)
Fuse Type: Cartridge, Glass (exact match required)
Mounting Type: Requires Holder (exact match required)
Operating Temperature Range: -55°C to 125°C (exact match required)

All substitute parts listed below meet these criteria. Variations in breaking capacity, melting I²t, DC cold resistance, and approval agencies do not preclude substitution when the above parameters are identical.

Parameter Comparison

Part Number	Series	Current (A)	Voltage (V AC)	Response Time	Package	Breaking Capacity (A)	Melting I²t	DC Cold Resistance (Ω)	Product Status	RoHS Status
02391.25H	239	1.25	250	Slow Blow	5x20mm	100	20.05	0.2	Obsolete	Non-compliant
02131.25MXBP	213	1.25	250	Slow Blow	5x20mm	35	27.15	0.0817	Active	ROHS3 Compliant
02131.25MXP	213	1.25	250	Slow Blow	5x20mm	35	27.15	0.0817	Active	ROHS3 Compliant
02131.25TXP	213	1.25	250	Slow Blow	5x20mm	35	27.15	0.0817	Active	ROHS3 Compliant
02181.25HXP	218	1.25	250	Slow Blow	5x20mm	35	12.65	0.0446	Active	ROHS3 Compliant
02181.25MXBP	218	1.25	250	Slow Blow	5x20mm	35	12.65	0.0446	Active	ROHS3 Compliant
02181.25MXP	218	1.25	250	Slow Blow	5x20mm	35	12.65	0.0446	Active	ROHS3 Compliant
02181.25TXP	218	1.25	250	Slow Blow	5x20mm	35	12.65	0.0446	Active	ROHS3 Compliant
02181.25VXP	218	1.25	250	Slow Blow	5x20mm	35	12.65	0.0446	Active	ROHS3 Compliant
02191.25MXABP	219XA	1.25	250	Slow Blow	5x20mm	150	27.15	0.0817	Active	ROHS3 Compliant
02191.25MXAF5P	219XA	1.25	250	Slow Blow	5x20mm	150	27.15	0.0817	Active	ROHS3 Compliant

Engineering Selection Recommendations

All listed substitute parts are active products with ROHS3 compliance, addressing the obsolescence and regulatory non-compliance status of the 02391.25H. Selection among substitutes should be based on:

Series 213 (02131.25MXBP, 02131.25MXP, 02131.25TXP): Active alternatives with broad international approval coverage (BSI, CCC, CE, CSA, PSE, SEMKO, UR, VDE). Suitable for applications requiring maximum regulatory flexibility.

Series 218 (02181.25HXP, 02181.25MXBP, 02181.25MXP, 02181.25TXP, 02181.25VXP): Active alternatives with comprehensive certification including K-MARK and UL approval. Lower DC cold resistance (0.0446 Ω) compared to Series 213 (0.0817 Ω) and original part (0.2 Ω). Melting I²t of 12.65 provides faster thermal response than the original 20.05.

Series 219XA (02191.25MXABP, 02191.25MXAF5P): Active alternatives with highest breaking capacity (150 A) and comprehensive international certifications. Melting I²t of 27.15 closely matches Series 213 characteristics.

All substitutes maintain identical current rating, voltage rating, response time, package dimensions, and operating temperature range as the original part.

Frequently Asked Questions (FAQ)

Q: Can any of these substitute parts directly replace the 02391.25H without modification?

A: Yes. All listed substitute parts share identical electrical ratings (1.25 A, 250 V AC), response time (slow blow), physical dimensions (5mm x 20mm), and mounting requirements (requires holder). Direct mechanical and electrical substitution is supported.

Q: What is the significance of different breaking capacities among the substitutes?

A: Breaking capacity indicates the maximum fault current the fuse can safely interrupt. The original 02391.25H has 100 A breaking capacity. Series 218 substitutes have 35 A, and Series 219XA substitutes have 150 A. For applications where fault current does not exceed the substitute's breaking capacity, substitution is valid. Applications with fault currents between 35 A and 100 A should use Series 219XA (150 A) substitutes.

Q: How do melting I²t values affect substitution suitability?

A: Melting I²t characterizes thermal response. The original part has 20.05; Series 213 and 219XA have 27.15; Series 218 have 12.65. Lower I²t values indicate faster thermal response. For applications sensitive to nuisance tripping, Series 213 or 219XA may be preferred. For applications requiring faster protection, Series 218 may be preferred. Substitution is valid when the application's inrush current profile is compatible with the substitute's thermal characteristics.

Q: What is the difference between packaging designations (MXBP, MXP, TXP, HXP, VXP)?

A: These designations indicate packaging and tape configuration for automated assembly. MXBP and MXP indicate bulk packaging; TXP, HXP, and VXP indicate tape-and-reel configurations. Electrical and mechanical specifications are identical across these variants. Selection depends on procurement and assembly requirements.

Q: Are all substitutes RoHS compliant?

A: Yes. All listed substitutes are ROHS3 compliant, addressing the non-compliance status of the obsolete 02391.25H. This is mandatory for applications subject to RoHS regulations.

Q: Which substitute has the broadest international certification coverage?

A: Series 218 parts (02181.25HXP, 02181.25MXBP, 02181.25MXP, 02181.25TXP, 02181.25VXP) include CCC, CE, CSA, K-MARK, PSE, SEMKO, UL, and VDE approvals, providing the most comprehensive global market acceptance.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message