Littelfuse 021706.3H Glass Cartridge Fuse 6.3A 250VAC 5x20mm Equivalent & Substitute Parts

Part Overview

The Littelfuse 021706.3H is a 6.3 A, 250 V AC/DC fast-blow glass cartridge fuse in 5mm x 20mm form factor, designed for use with fuse holders. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing system maintenance and new designs. The fuse provides circuit protection across industrial, commercial, and consumer applications requiring fast response to overcurrent conditions.

Key Parameters

Parameter	Value
Current Rating	6.3 A
Voltage Rating (AC)	250 V
Fuse Type	Cartridge, Glass
Response Time	Fast Blow
Package / Case	5mm x 20mm
Mounting Type	Requires Holder
Breaking Capacity @ Rated Voltage	63A
Operating Temperature Range	-55°C ~ 125°C

Substitute Part Grouping Explanation

Substitution for the 021706.3H is determined by strict equivalence across the following critical parameters:

Current Rating: 6.3 A (exact match required)
Voltage Rating: 250 V AC (exact match required)
Fuse Type: Cartridge, Glass (exact match required)
Response Time: Fast Blow (exact match required)
Physical Form Factor: 5mm x 20mm (exact match required)
Mounting Configuration: Requires Holder (exact match required)

All substitute parts listed below meet these criteria. Littelfuse parametric equivalents (021706.3HXP, 021706.3MXBP, 021706.3MXP, 021706.3TXP, 021706.3VXP, and 061706.3MXP) are direct functional replacements within the Littelfuse 217 and 617 series. Cross-manufacturer alternatives from Eaton, SCHURTER, and Bel Fuse provide equivalent electrical and mechanical performance for applications where multi-source qualification is required.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Current Rating (A)	Voltage (V AC)	Response Time	Package	Breaking Capacity (A)	Melting I²t	Product Status	RoHS Status
021706.3H	Littelfuse Inc.	6.3	250	Fast Blow	5x20mm	63	62.466	Obsolete	Non-compliant
021706.3HXP	Littelfuse Inc.	6.3	250	Fast Blow	5x20mm	63	62.465	Active	ROHS3 Compliant
021706.3MXBP	Littelfuse Inc.	6.3	250	Fast Blow	5x20mm	63	62.465	Active	ROHS3 Compliant
021706.3MXP	Littelfuse Inc.	6.3	250	Fast Blow	5x20mm	63	62.465	Active	ROHS3 Compliant
021706.3TXP	Littelfuse Inc.	6.3	250	Fast Blow	5x20mm	63	62.465	Active	ROHS3 Compliant
021706.3VXP	Littelfuse Inc.	6.3	250	Fast Blow	5x20mm	63	62.465	Active	ROHS3 Compliant
061706.3MXP	Littelfuse Inc.	6.3	250	Fast Blow	5x20mm	63	62.465	Active	ROHS3 Compliant
BK/GDB-6.3A	Eaton - Electronics Division	6.3	250	Fast Blow	5x20mm	63	69	Active	ROHS3 Compliant
0034.3885	SCHURTER Inc.	6.3	250	Fast Blow	5x20mm	200	40.8	Active	ROHS3 Compliant
5SF 6.3-R	Bel Fuse Inc.	6.3	250	Fast Blow	5x20mm	63	65	Active	ROHS3 Compliant
BK/S500-6.3-R	Eaton - Electronics Division	6.3	250	Fast Blow	5x20mm	63	69	Active	ROHS3 Compliant

Engineering Selection Recommendations

For applications currently using the obsolete 021706.3H, the Littelfuse parametric equivalents 021706.3HXP, 021706.3MXBP, 021706.3MXP, 021706.3TXP, 021706.3VXP, and 061706.3MXP are the primary recommended replacements. All are active products with ROHS3 compliance and identical electrical ratings. These parts maintain full compatibility with existing fuse holders and circuit designs.

Cross-manufacturer alternatives are qualified for applications requiring multi-source supply chains or where specific approval certifications are mandated. The Eaton BK/GDB-6.3A and BK/S500-6.3-R fuses provide equivalent performance with UL and VDE certifications. The Bel Fuse 5SF 6.3-R offers broad international approvals including cURus, IMQ, and SEMKO. The SCHURTER 0034.3885 provides the highest breaking capacity at 200A with cULus certification.

All substitute parts operate across the -55°C to 125°C temperature range and are suitable for direct replacement in existing designs. Selection should be based on supply availability, required approval certifications, and specific application voltage and current requirements.

Frequently Asked Questions (FAQ)

Q: Can I use any of these substitute parts interchangeably with the 021706.3H?

A: Yes, all listed substitute parts meet the core electrical and mechanical specifications: 6.3 A current rating, 250 V AC voltage rating, fast-blow response, and 5mm x 20mm form factor. Physical compatibility with existing fuse holders is maintained across all alternatives.

Q: What is the difference between Littelfuse parametric equivalents and cross-manufacturer alternatives?

A: Littelfuse parametric equivalents (021706.3HXP, 021706.3MXBP, 021706.3MXP, 021706.3TXP, 021706.3VXP, 061706.3MXP) are direct replacements from the same manufacturer with identical electrical characteristics and full design compatibility. Cross-manufacturer alternatives from Eaton, SCHURTER, and Bel Fuse provide equivalent functionality but may have different approval certifications and minor variations in melting I²t values.

Q: Why do some substitute parts have different melting I²t values?

A: Melting I²t represents the thermal energy required to melt the fuse element and is a characteristic of the specific fuse design. While all listed parts share the same 6.3 A current rating and fast-blow response, manufacturing differences result in slight variations. These variations remain within acceptable ranges for the specified application class.

Q: Are all substitute parts RoHS compliant?

A: All active substitute parts listed are ROHS3 compliant. The original 021706.3H is marked as RoHS non-compliant due to its obsolete status. Replacement with any active substitute part ensures compliance with current environmental regulations.

Q: What approval certifications should I consider for my application?

A: The original 021706.3H carries BSI, CCC, CE, CSA, KC, PSE, SEMKO, UR, and VDE approvals. Littelfuse parametric equivalents maintain these certifications. Cross-manufacturer alternatives carry different certification sets: Eaton parts include UL and VDE; Bel Fuse includes CCC, CE, CSA, cURus, IMQ, SEMKO, and VDE; SCHURTER includes cULus. Select based on your application's required regulatory approvals.

Q: Can I use the SCHURTER 0034.3885 as a direct replacement?

A: Yes, the SCHURTER 0034.3885 is electrically and mechanically compatible. However, it features a significantly higher breaking capacity of 200A compared to the 63A of the original part. This higher capacity does not affect normal operation but may be relevant for applications with specific breaking capacity requirements.

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