Littelfuse 021302.5MXBP Glass Cartridge Fuse 2.5A 250VAC 5x20mm Equivalent & Substitute Parts

Part Overview

The Littelfuse 021302.5MXBP is a 2.5 A, 250 V AC/DC glass cartridge fuse in 5mm x 20mm form factor, classified as a slow-blow fuse requiring a holder for installation. This component is active in production and widely used in industrial and consumer electronics for circuit protection. Equivalent and substitute parts are identified based on matching electrical ratings, mechanical dimensions, response characteristics, and regulatory compliance to ensure direct functional 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	35 A
Operating Temperature Range	-55°C to 125°C
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict equivalence across the following parameters:

Primary Matching Criteria (Mandatory for Direct Substitution):

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
Operating Temperature Range: -55°C to 125°C

Secondary Considerations (Allowable Variation):

Breaking Capacity: Rated at 35 A (main part); substitute parts range from 35 A to 150 A. Higher breaking capacity provides equivalent or enhanced protection capability.
Melting I²t: Varies across substitute parts (21.9 to 258). This parameter reflects thermal response characteristics and must be evaluated for specific circuit requirements.
DC Cold Resistance: Ranges from 0.0219 Ohms to 0.0583 Ohms. Variation within this range does not affect primary circuit protection function.
Approval Agencies: Substitute parts carry different certification combinations. All listed parts meet minimum regulatory requirements (CE, CSA, PSE, VDE, or equivalent).

All substitute parts listed maintain identical electrical and mechanical compatibility with the 021302.5MXBP within the specified parameter ranges.

Parameter Comparison

Part Number	Manufacturer	Series	Current Rating (A)	Voltage (V AC)	Response Time	Package	Breaking Capacity (A)	Melting I²t	DC Cold Resistance (Ohms)	RoHS Status
021302.5MXBP	Littelfuse Inc.	213	2.5	250	Slow Blow	5x20mm	35	138	0.0305	ROHS3
021302.5MXP	Littelfuse Inc.	213	2.5	250	Slow Blow	5x20mm	35	138	0.0305	ROHS3
021802.5HXP	Littelfuse	218	2.5	250	Slow Blow	5x20mm	35	23.25	0.0219	ROHS3
021802.5TXP	Littelfuse Inc.	218	2.5	250	Slow Blow	5x20mm	35	23.25	0.0219	ROHS3
021902.5MXAP	Littelfuse	219XA	2.5	250	Slow Blow	5x20mm	150	138	0.0305	ROHS3
023902.5HXP	Littelfuse	239	2.5	250	Slow Blow	5x20mm	100	79.705	0.0583	ROHS3
023902.5MXP	Littelfuse	239	2.5	250	Slow Blow	5x20mm	100	79.705	0.0583	ROHS3
0034.3121	SCHURTER Inc.	FST 5x20	2.5	250	Slow Blow	5x20mm	35	21.9	—	ROHS3
0034.5621.11	SCHURTER Inc.	SMD-FST	2.5	250	Slow Blow	5x20mm	35	21.9	—	ROHS3
0034.5717.11	SCHURTER Inc.	SMD-FTT	2.5	250	Slow Blow	5x20mm	35	258	—	ROHS3
TSC-2.5A	OptiFuse	TSC	2.5	250	Slow Blow	5x20mm	100	24.49	—	ROHS3

Engineering Selection Recommendations

All substitute parts listed maintain active product status and full ROHS3 compliance. Selection among equivalents should be based on the following factors:

Littelfuse Series 213 & 218 (021302.5MXP, 021802.5HXP, 021802.5TXP): Direct Littelfuse alternatives with identical or near-identical electrical characteristics. Series 213 and 218 differ primarily in melting I²t and DC cold resistance. Both series carry comprehensive regulatory approvals including BSI, CCC, CE, CSA, PSE, SEMKO, UL, and VDE certifications.

Littelfuse Series 219XA (021902.5MXAP): Offers enhanced breaking capacity of 150 A compared to the 35 A rating of the main part, with identical melting I²t (138) and DC cold resistance (0.0305 Ohms). Suitable for applications requiring higher fault current withstand capability.

Littelfuse Series 239 (023902.5HXP, 023902.5MXP): Intermediate breaking capacity of 100 A with moderate melting I²t (79.705). Certifications include CE, CSA, KC, PSE, and UL. Appropriate for circuits with moderate fault current levels.

SCHURTER FST Series (0034.3121, 0034.5621.11, 0034.5717.11): Cross-manufacturer alternatives with identical electrical ratings. FST and SMD-FST variants carry cURus and VDE approvals. The SMD-FTT variant (0034.5717.11) features significantly higher melting I²t (258), suitable for circuits with extended thermal tolerance requirements.

OptiFuse TSC Series (TSC-2.5A): Cross-manufacturer option with 100 A breaking capacity and UL 248 certification. Melting I²t of 24.49 provides fast thermal response characteristics.

Frequently Asked Questions (FAQ)

Q: Can I substitute the 021302.5MXBP with any of the listed parts without circuit modification?

A: Yes. All listed substitute parts maintain identical current rating (2.5 A), voltage rating (250 V AC), response time (slow blow), and mechanical package (5x20mm). Direct substitution is electrically and mechanically compatible. No circuit modification is required.

Q: What is the significance of different breaking capacity ratings (35 A, 100 A, 150 A)?

A: Breaking capacity indicates the maximum fault current the fuse can safely interrupt without rupturing or creating a hazard. Higher breaking capacity provides enhanced protection in circuits with higher available fault currents. The main part is rated 35 A; substitute parts with 100 A or 150 A ratings provide equivalent or superior fault current handling. Selection depends on the specific circuit's available fault current level.

Q: How does melting I²t affect fuse selection?

A: Melting I²t is a thermal characteristic that determines how quickly the fuse element responds to overcurrent. Lower I²t values indicate faster response; higher values indicate slower response. The main part has I²t of 138. Substitute parts range from 21.9 to 258. For direct substitution in existing circuits, parts with similar I²t values (within the 20–140 range) are preferred. Parts with significantly higher I²t (such as 0034.5717.11 at 258) are suitable only if the circuit design accommodates extended thermal response time.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed substitute parts carry ROHS3 compliance certification, matching the environmental compliance status of the main part.

Q: Which substitute part has the widest regulatory approval coverage?

A: The Littelfuse Series 213 and 218 parts (021302.5MXP, 021802.5HXP, 021802.5TXP) carry the most comprehensive approval agency certifications, including BSI, CCC, CE, CSA, PSE, SEMKO, UL, and VDE. These are recommended for applications requiring broad international regulatory acceptance.

Q: Can I use a substitute part with higher breaking capacity in a circuit designed for 35 A breaking capacity?

A: Yes. Higher breaking capacity (100 A or 150 A) provides enhanced fault current withstand capability and is fully compatible with circuits designed for lower breaking capacity. The fuse will operate identically under normal and overload conditions; the higher breaking capacity only provides additional safety margin during fault events.

Q: What is the difference between Littelfuse and SCHURTER fuses in this list?

A: Both manufacturers produce glass cartridge fuses meeting identical electrical and mechanical specifications for this 2.5 A, 250 V application. Littelfuse parts carry broader regulatory approvals (including BSI and UR). SCHURTER parts carry cURus and VDE certifications. Both are suitable for direct substitution; selection may depend on supply chain availability or specific regional certification requirements.

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