Littelfuse 20102500021 Glass Cartridge Fuse 250mA 250VAC 5x20mm - Equivalent & Substitute Parts

Part Overview

The Littelfuse 20102500021 is a 250 mA, 250 V AC/DC glass cartridge fuse in 5mm x 20mm form factor, designed for circuit protection in applications requiring medium-blow response characteristics. This component is classified as Active product status and requires a compatible fuse holder for installation. Substitute parts may be necessary due to inventory constraints, supply chain considerations, or specific application requirements where alternative manufacturers' components meet identical electrical and mechanical specifications.

Substiute Parts

20102500021

Littelfuse Inc.In Stock: 105120102500021 Datasheet

Current PartRFQ

20102500021P

Littelfuse Inc.In Stock: 98120102500021P Datasheet

Parametric EquivalentRFQ

BK1/GMC-250-R

Eaton - Electronics DivisionIn Stock: 1963BK1/GMC-250-R Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the Littelfuse 20102500021 are qualified based on strict equivalence of the following electrical and mechanical parameters:

• Current Rating: 250 mA (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: Medium Blow (exact match required)
• Mounting Type: Requires Holder (exact match required)

Two substitute parts meet these criteria: the Littelfuse 20102500021P (parametric equivalent from the same manufacturer) and the Eaton BK1/GMC-250-R (manufacturer-recommended alternative). Both components share identical current, voltage, package dimensions, and fuse classification, enabling direct functional substitution in circuit protection applications.

Parameter Comparison

Engineering Selection Recommendations

All three components—Littelfuse 20102500021, Littelfuse 20102500021P, and Eaton BK1/GMC-250-R—are Active product status and meet ROHS3 compliance requirements. The Littelfuse 20102500021P represents a direct parametric equivalent within the same manufacturer's product line, maintaining identical electrical characteristics and certifications (cULus approval). The Eaton BK1/GMC-250-R is manufacturer-recommended and provides broader regulatory approval (CSA, KC, UL), though it exhibits lower breaking capacity (35A versus 80A) and reduced melting I²t (0.046 versus 0.13). Selection between these substitutes should be based on application-specific breaking capacity requirements and regulatory jurisdiction compliance needs.

Frequently Asked Questions (FAQ)

Q: Can the Littelfuse 20102500021P be used as a direct replacement for the Littelfuse 20102500021?

A: Yes. Both components share identical current rating (250 mA), voltage rating (250 V AC), package dimensions (5mm x 20mm), fuse type (cartridge, glass), response time (medium blow), and breaking capacity (80A). They are parametrically equivalent and interchangeable.

Q: What are the key differences between the Littelfuse 20102500021 and the Eaton BK1/GMC-250-R?

A: The primary differences are breaking capacity and melting I²t. The Littelfuse component has 80A breaking capacity and 0.13 melting I²t, while the Eaton component has 35A breaking capacity and 0.046 melting I²t. Both maintain identical current, voltage, and package specifications. Regulatory approvals also differ: Littelfuse carries cULus certification, while Eaton carries CSA, KC, and UL certifications.

Q: Are all three fuses compatible with the same holder?

A: Yes. All three components share the identical 5mm x 20mm package dimensions and require a compatible 5x20mm fuse holder. Physical installation compatibility is assured across all three parts.

Q: Which substitute should I select for applications requiring maximum breaking capacity?

A: The Littelfuse 20102500021 and Littelfuse 20102500021P both provide 80A breaking capacity, which exceeds the Eaton BK1/GMC-250-R at 35A. Selection should be based on application fault current levels and circuit protection requirements.

Q: Do all three components meet RoHS compliance?

A: Yes. All three parts are ROHS3 compliant and suitable for applications requiring RoHS-compliant components.