SCHURTER 0034.3780 Glass Cartridge Fuse 2.5A 250VAC 5x20mm Equivalent & Substitute Parts

Part Overview

The SCHURTER 0034.3780 is a 2.5A 250VAC glass cartridge fuse in 5x20mm form factor, designed for circuit protection in AC/DC applications. This slow-blow fuse cartridge requires a holder for installation and is actively manufactured. Equivalent and substitute parts are identified based on matching electrical ratings, mechanical dimensions, and functional performance characteristics to ensure direct interchangeability in protected circuits.

Key Parameters

Parameter	Value
Current Rating	2.5 A
Voltage Rating (AC)	250 V
Fuse Type	Cartridge, Glass
Response Time	Slow Blow
Package / Case	5mm x 20mm
Mounting Type	Requires Holder
Breaking Capacity @ Rated Voltage	100A
Operating Temperature Range	-40°C ~ 85°C
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict alignment with the following electrical and mechanical parameters:

Current Rating: 2.5 A (exact match required)
Voltage Rating (AC): 250 V (exact match required)
Package / Case: 5mm x 20mm (exact match required)
Fuse Type: Cartridge, Glass (exact match required)
Response Time: Slow Blow (exact match required)
Mounting Type: Requires Holder (exact match required)

Substitute parts are grouped into two categories based on breaking capacity and thermal characteristics:

Parametric Equivalents (Breaking Capacity 35A): Parts with identical electrical and mechanical specifications but lower breaking capacity, suitable for applications where 35A breaking capacity is sufficient.

Direct Equivalents (Breaking Capacity 100A): Parts with identical electrical, mechanical, and performance specifications, including matching breaking capacity.

Similar Parts (Breaking Capacity 35A, Variant Characteristics): Parts meeting core electrical and mechanical requirements with variations in melting I²t, DC cold resistance, or operating temperature range.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Series	Current Rating (A)	Voltage Rating (V AC)	Package	Response Time	Breaking Capacity (A)	Melting I²t	Operating Temperature	Approval Agency	Inventory (Pcs)
0034.3780	SCHURTER Inc.	FSL 5x20	2.5	250	5x20mm	Slow Blow	100	9.45	-40°C ~ 85°C	cULus	1752
0034.5047	SCHURTER Inc.	FTT 5x20	2.5	250	5x20mm	Slow Blow	35	258	-40°C ~ 85°C	cURus	1232
023902.5MXP	Littelfuse	239	2.5	250	5x20mm	Slow Blow	100	79.705	-55°C ~ 125°C	CE, CSA, KC, PSE, UL	3140
021302.5MXP	Littelfuse Inc.	213	2.5	250	5x20mm	Slow Blow	35	138	-55°C ~ 125°C	BSI, CCC, CE, CSA, PSE, SEMKO, UR, VDE	1732
021802.5HXP	Littelfuse	218	2.5	250	5x20mm	Slow Blow	35	23.25	-55°C ~ 125°C	CCC, CE, CSA, K-MARK, PSE, SEMKO, UL, VDE	21272
021802.5MXP	Littelfuse Inc.	218	2.5	250	5x20mm	Slow Blow	35	23.25	-55°C ~ 125°C	CCC, CE, CSA, K-MARK, PSE, SEMKO, UL, VDE	11400
5TT 2.5-R	Bel Fuse Inc.	5TT	2.5	250	5x20mm	Slow Blow	100	45	-55°C ~ 125°C	CE, CSA, cULus, PSE	2593

Engineering Selection Recommendations

Direct Replacement (100A Breaking Capacity):

Littelfuse 023902.5MXP: Maintains 100A breaking capacity with extended operating temperature range (-55°C ~ 125°C). Broader certification coverage (CE, CSA, KC, PSE, UL) supports global deployment. Higher inventory availability (3140 pcs).
Bel Fuse 5TT 2.5-R: Maintains 100A breaking capacity with extended operating temperature range (-55°C ~ 125°C). Certified for CE, CSA, cULus, PSE standards.

Parametric Equivalent (35A Breaking Capacity):

SCHURTER 0034.5047: Same manufacturer as primary part, maintains SCHURTER series continuity. Reduced breaking capacity suitable for lower-fault-current applications.
Littelfuse 021802.5HXP: Highest inventory availability (21272 pcs). Lowest melting I²t (23.25) provides fastest response. Comprehensive international certifications (CCC, CE, CSA, K-MARK, PSE, SEMKO, UL, VDE).
Littelfuse 021802.5MXP: Identical electrical and thermal characteristics to 021802.5HXP with 11400 pcs inventory.
Littelfuse 021302.5MXP: Extended certification coverage (BSI, CCC, CE, CSA, PSE, SEMKO, UR, VDE) for specialized regional requirements.

Selection between 100A and 35A breaking capacity variants depends on circuit fault-current levels. Applications with fault currents exceeding 35A require 100A-rated substitutes.

Frequently Asked Questions (FAQ)

Q: Can I substitute a 35A breaking capacity fuse for the original 100A SCHURTER 0034.3780?

A: Substitution is permissible only if the circuit's maximum available fault current does not exceed 35A. If fault current may exceed 35A, the fuse cannot safely interrupt the circuit, and a 100A-rated substitute (023902.5MXP or 5TT 2.5-R) is required.

Q: Are all substitute parts mechanically compatible with the same fuse holder?

A: Yes. All listed substitutes maintain the 5x20mm form factor and require-holder mounting type, ensuring mechanical compatibility with standard 5x20mm fuse holders.

Q: What is the difference between melting I²t values across substitute parts?

A: Melting I²t indicates the thermal energy required to melt the fuse element. Lower values (021802.5HXP at 23.25) provide faster response to overcurrent conditions. Higher values (0034.5047 at 258) provide greater tolerance to transient current spikes. Selection depends on circuit sensitivity to inrush currents.

Q: Which substitute offers the widest operating temperature range?

A: Littelfuse 023902.5MXP, 021302.5MXP, 021802.5HXP, 021802.5MXP, and Bel Fuse 5TT 2.5-R all operate across -55°C ~ 125°C, compared to the original part's -40°C ~ 85°C range.

Q: Are all substitutes RoHS3 compliant?

A: Yes. All listed substitute parts are ROHS3 compliant and REACH unaffected, matching the environmental compliance status of the original SCHURTER 0034.3780.

Q: Which substitute has the highest inventory availability?

A: Littelfuse 021802.5HXP offers the highest stock level at 21272 pcs, followed by 021802.5MXP at 11400 pcs.

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