Littelfuse 20105000021 Glass Cartridge Fuse 500mA 250VAC 5x20mm Equivalent & Substitute Parts

Part Overview

The Littelfuse 20105000021 is a 500mA 250VAC glass cartridge fuse in 5x20mm form factor, designed for circuit protection in AC and DC applications. This Active product requires a fuse holder for installation and is cULus approved. Equivalent and substitute parts are identified based on matching electrical ratings, mechanical dimensions, and performance characteristics to ensure direct functional replacement in protected circuits.

Substiute Parts

20105000021

Littelfuse Inc.In Stock: 114520105000021 Datasheet

Current PartRFQ

20105000001

Littelfuse Inc.In Stock: 302220105000001 Datasheet

Parametric EquivalentRFQ

20105000021P

Littelfuse Inc.In Stock: 96220105000021P Datasheet

Parametric EquivalentRFQ

BK1/GMC-500-R

Eaton - Electronics DivisionIn Stock: 2032BK1/GMC-500-R Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility is determined by matching the following critical parameters:

• Current Rating: 500 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)

All identified substitutes meet these core electrical and mechanical requirements. Variations in Breaking Capacity and Melting I²t are noted but do not preclude substitution when circuit protection requirements align with the specified ratings.

Parameter Comparison

Engineering Selection Recommendations

All four parts listed are Active products with current regulatory compliance (ROHS3 Compliant, REACH Unaffected). Selection between Littelfuse 20105000021, 20105000001, and 20105000021P is interchangeable from an electrical and mechanical standpoint, with identical Breaking Capacity (80A) and Melting I²t (0.35) characteristics.

The Eaton BK1/GMC-500-R is functionally equivalent for 500mA 250VAC protection in 5x20mm form factor. However, it exhibits a lower Breaking Capacity (35A versus 80A) and slightly higher Melting I²t (0.41 versus 0.35). This part carries CSA, KC, and UL approvals, providing alternative certification pathways. Selection of the Eaton part is appropriate when supply constraints exist or when system certifications specifically require Eaton components.

Frequently Asked Questions (FAQ)

Q: Can I substitute 20105000001 for 20105000021? A: Yes. Both parts are Littelfuse Series 201 glass cartridge fuses with identical electrical ratings (500mA, 250VAC), mechanical dimensions (5x20mm), response time (Medium Blow), Breaking Capacity (80A), and Melting I²t (0.35). They are direct functional equivalents.

Q: What is the difference between 20105000021 and 20105000021P? A: The 20105000021P belongs to Series 201P while 20105000021 belongs to Series 201. All electrical and mechanical parameters are identical. The series designation may reflect manufacturing process or packaging variations, but substitution is functionally valid.

Q: Can I use the Eaton BK1/GMC-500-R as a substitute? A: Yes, with engineering review. The Eaton part matches all critical parameters: 500mA current rating, 250VAC voltage rating, 5x20mm dimensions, Medium Blow response, and Cartridge Glass type. However, it has a lower Breaking Capacity (35A versus 80A) and higher Melting I²t (0.41 versus 0.35). Verify that your circuit protection requirements are satisfied by these performance characteristics before substitution.

Q: Do all these fuses require the same holder? A: Yes. All four parts are 5x20mm cartridge fuses requiring a compatible 5x20mm fuse holder. Mechanical installation is identical across all substitutes.

Q: Are there any compliance differences between these parts? A: Littelfuse parts carry cULus approval. The Eaton BK1/GMC-500-R carries CSA, KC, and UL approvals. All parts are ROHS3 Compliant and REACH Unaffected. Select based on your system's required certification pathway.