Littelfuse 20111250001P Glass Cartridge Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 20111250001P is an active-status glass cartridge fuse rated at 1.25 A, 250 V AC, with a 5mm x 20mm form factor. This fuse is designed for applications requiring medium-blow response characteristics and operates within the temperature range of -25°C to 70°C. The part is ROHS3 compliant and holds cULus approval certification. Identifying equivalent and substitute parts becomes necessary when managing inventory across multiple suppliers, accommodating regional availability constraints, or addressing supply chain disruptions while maintaining identical electrical and mechanical performance specifications.

Substiute Parts

20111250001P

Littelfuse Inc.In Stock: 78920111250001P Datasheet

Current PartRFQ

20111250021

Littelfuse Inc.In Stock: 119620111250021 Datasheet

Parametric EquivalentRFQ

0034.2517

SCHURTER Inc.In Stock: 17000034.2517 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 20111250001P is determined by strict equivalence across the following critical parameters: current rating (1.25 A), AC voltage rating (250 V), fuse type (cartridge, glass), physical package dimensions (5mm x 20mm), response time classification (medium blow), and breaking capacity (80 A). All identified substitutes maintain these core electrical and mechanical specifications, ensuring direct functional interchangeability within applications designed for the primary part number.

The substitute parts are grouped as follows:

Parametric Equivalent (Littelfuse 20111250021): Identical electrical ratings, response characteristics, and physical dimensions. Differs only in series designation (201 versus 201P) and inventory status.

Direct Manufacturer Substitute (SCHURTER 0034.2517): Matches all critical electrical parameters for AC operation and physical form factor. Provides additional DC voltage rating (125 V DC) not specified in the primary part. Operates across an extended temperature range (-40°C to 85°C) and carries ROHS3 compliance.

Parameter Comparison

Engineering Selection Recommendations

Littelfuse 20111250021: This part is recommended as the primary substitute for the 20111250001P. Both parts are manufactured by Littelfuse Inc., carry identical electrical specifications, and hold cULus approval certification. The 20111250021 maintains active product status and provides equivalent performance across all critical parameters. Selection of this substitute is appropriate for applications where Littelfuse brand continuity and cULus certification are required.

SCHURTER 0034.2517: This part is suitable as an alternative substitute when extended temperature range operation (-40°C to 85°C versus -25°C to 70°C) is beneficial to the application. The SCHURTER fuse maintains ROHS3 compliance and matches all AC voltage and current specifications. The additional DC voltage rating (125 V) provides operational flexibility in mixed AC/DC circuit environments. Note that this part does not carry cULus certification; applications requiring cULus approval should prioritize the Littelfuse options.

Frequently Asked Questions (FAQ)

Q: Can the 20111250021 be used as a direct replacement for the 20111250001P?

A: Yes. Both parts are manufactured by Littelfuse Inc. and share identical current ratings (1.25 A), AC voltage ratings (250 V), physical dimensions (5mm x 20mm), response time (medium blow), and breaking capacity (80 A). The parts differ only in series designation and are functionally equivalent.

Q: What is the primary difference between the Littelfuse and SCHURTER substitutes?

A: The Littelfuse 20111250021 maintains identical specifications to the primary part, including cULus certification. The SCHURTER 0034.2517 offers an extended operating temperature range (-40°C to 85°C) and includes a DC voltage rating (125 V), but does not carry cULus approval. Selection depends on certification requirements and temperature environment specifications.

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

A: Yes. All three parts share the identical 5mm x 20mm physical form factor and require a compatible fuse holder. No mechanical modifications or holder changes are necessary when substituting between these parts.

Q: Does the SCHURTER part's higher melting I²t value (5.47 versus 3.2) affect substitution suitability?

A: The melting I²t value is a thermal characteristic that influences fuse response time under fault conditions. The SCHURTER part maintains the same medium-blow response classification as the primary part. Applications designed for the 20111250001P will operate within acceptable parameters with the SCHURTER substitute; however, the difference in I²t should be noted for circuits with specific thermal response requirements.

Q: Which substitute should be selected for applications requiring regulatory certification?

A: For applications requiring cULus certification, select either the primary part (20111250001P) or the Littelfuse substitute (20111250021). The SCHURTER 0034.2517 does not carry cULus approval and should not be used in applications where this certification is mandatory.