5VT 6.3-R Equivalent & Substitute Parts

Part Overview

The 5VT 6.3-R is a 6.3 A, 250 V AC/DC glass cartridge fuse manufactured by Bel Fuse Inc. in a 5mm x 20mm package with slow-blow response characteristics. This part is classified as obsolete, making equivalent substitutes necessary for ongoing system maintenance and new designs. Substitute parts must maintain identical electrical ratings, mechanical dimensions, and response time characteristics to ensure proper circuit protection without modification to existing fuse holders.

Key Parameters

Parameter	Value
Current Rating	6.3 A
Voltage Rating (AC)	250 V
Fuse Type	Cartridge, Glass
Package / Case	5mm x 20mm
Response Time	Slow Blow
Mounting Type	Requires Holder
Breaking Capacity @ Rated Voltage	63 A
Operating Temperature Range	-55°C ~ 125°C
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution for the 5VT 6.3-R is determined by strict equivalence across the following parameters:

Current Rating: 6.3 A (exact match required)
Voltage Rating: 250 V AC (exact match required)
Package Dimensions: 5mm x 20mm (exact match required)
Fuse Type: Cartridge, Glass (exact match required)
Response Time: Slow Blow (exact match required)
Breaking Capacity: 63 A (exact match required)

All identified substitute parts meet these criteria. Variations in melting I²t values and DC cold resistance are within acceptable engineering tolerances for this component category and do not affect functional interchangeability in standard circuit protection applications.

Parameter Comparison

Part Number	Manufacturer	Current Rating (A)	Voltage Rating (V AC)	Package	Response Time	Breaking Capacity (A)	Melting I²t	DC Cold Resistance (Ohms)	Product Status	Inventory (Pcs)
5VT 6.3-R	Bel Fuse Inc.	6.3	250	5mm x 20mm	Slow Blow	63	658	0.009	Obsolete	777
021306.3MXP	Littelfuse Inc.	6.3	250	5mm x 20mm	Slow Blow	63	600	0.0095	Active	1719
021806.3HXP	Littelfuse Inc.	6.3	250	5mm x 20mm	Slow Blow	63	198.5	0.0076	Active	1600
021806.3MXP	Littelfuse Inc.	6.3	250	5mm x 20mm	Slow Blow	63	198.5	0.0076	Active	2743
021806.3TXP	Littelfuse Inc.	6.3	250	5mm x 20mm	Slow Blow	63	198.5	0.0076	Active	990
021806.3VXP	Littelfuse Inc.	6.3	250	5mm x 20mm	Slow Blow	63	198.5	0.0076	Active	951
GDC-6.3A	Eaton - Electronics Division	6.3	250	5mm x 20mm	Slow Blow	63	237.6	0.0071	Active	1134

Engineering Selection Recommendations

All substitute parts listed are functionally equivalent to the 5VT 6.3-R and are suitable for direct replacement in existing applications. Selection should be based on the following criteria:

Product Status: All substitute parts carry Active product status, ensuring long-term availability and supply chain continuity compared to the obsolete 5VT 6.3-R.

Compliance & Certifications: The Littelfuse 021306.3MXP, 021806.3HXP, 021806.3MXP, 021806.3TXP, and 021806.3VXP parts maintain comprehensive approval agency coverage including CCC, CE, CSA, and VDE certifications. The Eaton GDC-6.3A carries cURus, IMQ, and MITI/JET certifications. Selection should align with the specific regulatory requirements of the target application.

Inventory Availability: The Littelfuse 021806.3MXP offers the highest inventory level at 2743 pieces, followed by 021306.3MXP at 1719 pieces, providing optimal supply security for high-volume requirements.

Thermal Performance: All parts operate within the -55°C to 125°C temperature range, maintaining compatibility with the original specification.

Frequently Asked Questions (FAQ)

Q: Can the 5VT 6.3-R be directly replaced with any of the listed substitutes?

A: Yes. All listed substitute parts maintain identical current ratings (6.3 A), voltage ratings (250 V AC), package dimensions (5mm x 20mm), response time (slow blow), and breaking capacity (63 A). Direct replacement in existing fuse holders is supported without modification.

Q: What is the significance of the different melting I²t values among the substitutes?

A: Melting I²t represents the thermal energy required to melt the fuse element. Variations among the listed parts (ranging from 198.5 to 658) fall within acceptable engineering tolerances for this component category and do not affect functional interchangeability in standard circuit protection applications.

Q: Why is the 5VT 6.3-R classified as obsolete?

A: Obsolete status indicates that the manufacturer has discontinued production. Substitute parts with Active status ensure continued availability for system maintenance and new designs.

Q: Are there any compliance differences between the substitute options?

A: All substitutes maintain ROHS3 compliance and REACH Unaffected status. Approval agency coverage varies slightly; the Littelfuse series includes broader international certifications (CCC, CE, CSA, K-MARK, PSE, SEMKO, UL, VDE), while the Eaton GDC-6.3A carries cURus, IMQ, and MITI/JET certifications. Selection should align with target market regulatory requirements.

Q: Can these parts be used interchangeably in the same circuit?

A: Yes. All parts are mechanically and electrically equivalent for the specified 6.3 A, 250 V AC/DC application with 5mm x 20mm package requirements. No circuit modifications are necessary.

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