Bel Fuse Inc. 5VT 1 Glass Cartridge Fuse - Equivalent & Substitute Parts

Part Overview

The Bel Fuse Inc. 5VT 1 is a 1 A, 250 V AC/DC slow-blow glass cartridge fuse in 5mm x 20mm form factor, designed for circuit protection in industrial and commercial applications. This part is classified as obsolete, making identification of active equivalent and substitute components essential for ongoing system maintenance, repairs, and new designs requiring compatible protection devices.

Key Parameters

Parameter	Value
Current Rating	1 A
Voltage Rating (AC)	250 V
Fuse Type	Cartridge, Glass
Response Time	Slow Blow
Package / Case	5mm x 20mm
Mounting Type	Requires Holder
Operating Temperature Range	-55°C to 125°C
Breaking Capacity @ Rated Voltage	35 A
Melting I²t	28
DC Cold Resistance	0.11 Ohms

Substitute Part Grouping Explanation

Substitution of the 5VT 1 is determined by strict equivalence across the following critical parameters:

Current Rating: 1 A (exact match required)
Voltage Rating: 250 V AC (exact match required)
Fuse Type: Cartridge, Glass (exact match required)
Response Time: Slow Blow (exact match required)
Package / Case: 5mm x 20mm (exact match required)
Mounting Type: Requires Holder (exact match required)
Operating Temperature Range: -55°C to 125°C (minimum requirement)

Parametric equivalents from Bel Fuse Inc. (5ET 1-R, 5ST 1-R, 5TT 1-R) meet all critical electrical and mechanical parameters. Similar parts from Littelfuse Inc. and Eaton Electronics Division satisfy the same functional requirements with minor dimensional tolerances within industry standards. Breaking capacity and melting I²t values vary among substitutes and must be evaluated against specific circuit protection requirements.

Parameter Comparison

Part Number	Manufacturer	Current (A)	Voltage (V AC)	Response Time	Package	Breaking Capacity (A)	Melting I²t	DC Resistance (Ω)	Product Status	RoHS Status
5VT 1	Bel Fuse Inc.	1	250	Slow Blow	5x20mm	35	28	0.11	Obsolete	Non-compliant
5ET 1-R	Bel Fuse Inc.	1	250	Slow Blow	5x20mm	150	28	0.11	Active	ROHS3 Compliant
5ST 1-R	Bel Fuse Inc.	1	250	Slow Blow	5x20mm	35	2.4	0.095	Active	ROHS3 Compliant
5TT 1-R	Bel Fuse Inc.	1	250	Slow Blow	5x20mm	100	8.63	0.27	Active	ROHS3 Compliant
0213001.MXP	Littelfuse Inc.	1	250	Slow Blow	5x20mm	35	19.2	0.1165	Active	ROHS3 Compliant
0218001.MXP	Littelfuse Inc.	1	250	Slow Blow	5x20mm	35	6.73	0.0613	Active	ROHS3 Compliant
0218001.TXP	Littelfuse Inc.	1	250	Slow Blow	5x20mm	35	6.73	0.0613	Active	ROHS3 Compliant
0219001.MXAP	Littelfuse Inc.	1	250	Slow Blow	5x20mm	150	19.2	0.1165	Active	ROHS3 Compliant
0239001.HXP	Littelfuse Inc.	1	250	Slow Blow	5x20mm	35	11.295	0.2965	Active	ROHS3 Compliant
BK1/GMD-1-R	Eaton - Electronics Division	1	250	Slow Blow	5x20mm	100	12	0.3065	Active	ROHS3 Compliant

Engineering Selection Recommendations

For direct replacement of the obsolete 5VT 1, the Bel Fuse Inc. 5ET 1-R is the primary parametric equivalent, offering identical electrical characteristics (1 A, 250 V, 28 melting I²t) with active product status and ROHS3 compliance. The 5ET 1-R maintains the same breaking capacity (150 A) and DC cold resistance (0.11 Ohms) as the original part.

When Bel Fuse equivalents are unavailable, Littelfuse Inc. 0218001.MXP and 0218001.TXP provide functional substitution with identical current and voltage ratings, though with reduced melting I²t (6.73 versus 28). These parts are suitable for applications where faster response characteristics are acceptable. The 0219001.MXAP variant offers higher breaking capacity (150 A) for circuits requiring enhanced fault current handling.

For applications requiring exact thermal response matching, the 5ST 1-R presents a faster-acting alternative (melting I²t 2.4) suitable only where circuit design accommodates reduced thermal tolerance. The 5TT 1-R provides intermediate response characteristics (melting I²t 8.63) with 100 A breaking capacity.

All recommended substitutes maintain the 5mm x 20mm form factor, -55°C to 125°C operating temperature range, and slow-blow response classification. Selection should account for specific circuit protection requirements, regulatory compliance mandates, and thermal response characteristics of the target application.

Frequently Asked Questions (FAQ)

Q: Can the 5VT 1 be directly replaced with any of the listed substitutes?

A: Yes, all listed parts meet the core functional requirements: 1 A current rating, 250 V AC voltage rating, slow-blow response, and 5mm x 20mm form factor. However, differences in melting I²t and breaking capacity must be evaluated against specific circuit protection requirements.

Q: What is the difference between parametric equivalents and similar parts?

A: Parametric equivalents (5ET 1-R, 5ST 1-R, 5TT 1-R from Bel Fuse Inc.) are from the same manufacturer and maintain identical core electrical specifications. Similar parts from Littelfuse Inc. and Eaton satisfy the same functional requirements but may have minor variations in thermal response and breaking capacity.

Q: Does the 5VT 1 require a specific holder for installation?

A: Yes, the 5VT 1 is a cartridge fuse requiring a dedicated fuse holder. All substitute parts listed maintain this requirement and are compatible with standard 5mm x 20mm fuse holders.

Q: Are all substitutes RoHS compliant?

A: The original 5VT 1 is RoHS non-compliant. All active substitute parts listed (5ET 1-R, 5ST 1-R, 5TT 1-R, and Littelfuse variants) are ROHS3 compliant, meeting current environmental regulations.

Q: How do melting I²t values affect fuse selection?

A: Melting I²t determines the thermal response time of the fuse. The original 5VT 1 has a melting I²t of 28. Substitutes with lower values (such as 0218001.MXP at 6.73) respond faster to overcurrent conditions. Selection must match the circuit's thermal protection requirements.

Q: What is the significance of breaking capacity differences?

A: Breaking capacity indicates the maximum fault current the fuse can safely interrupt. The 5VT 1 has 35 A breaking capacity. Substitutes with higher breaking capacity (5ET 1-R at 150 A, 0219001.MXAP at 150 A) provide enhanced protection in circuits with higher available fault currents.

Q: Can substitutes with different DC cold resistance values be used interchangeably?

A: DC cold resistance affects voltage drop and heat generation under normal operating conditions. Substitutes with significantly different resistance values (ranging from 0.0613 Ω to 0.3065 Ω) may impact circuit performance. Selection should consider the specific circuit's sensitivity to resistance variations.

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