5TT 2 Glass Cartridge Fuse - Equivalent & Substitute Parts

Part Overview

The 5TT 2 is a 2A 250VAC glass cartridge fuse manufactured by Bel Fuse Inc., designed for 5mm x 20mm holder applications. This component is classified as obsolete, making equivalent substitute parts necessary for ongoing system maintenance and new design implementations. The slow-blow response characteristic and 100A breaking capacity define its operational profile in circuit protection applications.

Key Parameters

Parameter	Value
Current Rating	2 A
Voltage Rating (AC)	250 V
Package / Case	5mm x 20mm
Fuse Type	Cartridge, Glass
Response Time	Slow Blow
Mounting Type	Requires Holder
Operating Temperature Range	-55°C ~ 125°C

Substitute Part Grouping Explanation

Substitute parts for the 5TT 2 are qualified based on strict parameter matching across electrical and mechanical specifications. All substitute candidates maintain identical current rating (2A), voltage rating (250VAC), physical dimensions (5mm x 20mm), fuse type (cartridge glass), response characteristic (slow blow), and operating temperature range (-55°C to 125°C). These parameters are mandatory for functional interchangeability in holder-based applications.

Substitutes are differentiated by breaking capacity, melting I²t values, DC cold resistance, approval certifications, and product status. The 5TT 2-R serves as a direct manufacturer equivalent with active product status. The 5ET 2-R and 5ST 2-R represent parametric equivalents with enhanced certification coverage and active availability.

Parameter Comparison

Parameter	5TT 2	5TT 2-R	5ET 2-R	5ST 2-R
Manufacturer	Bel Fuse Inc.	Bel Fuse Inc.	Bel Fuse Inc.	Bel Fuse Inc.
Current Rating (Amps)	2 A	2 A	2 A	2 A
Voltage Rating - AC	250 V	250 V	250 V	250 V
Package / Case	5mm x 20mm	5mm x 20mm	5mm x 20mm	5mm x 20mm
Fuse Type	Cartridge, Glass	Cartridge, Glass	Cartridge, Glass	Cartridge, Glass
Response Time	Slow Blow	Slow Blow	Slow Blow	Slow Blow
Operating Temperature	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C
Breaking Capacity @ Rated Voltage	100A	100A	150A	35A
Melting I²t	30	29.9	92	12
DC Cold Resistance	0.09 Ohms	0.08 Ohms	0.043 Ohms	0.03 Ohms
Product Status	Obsolete	Active	Active	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Approval Agency	CE, CSA, PSE, UL	CE, CSA, cULus, PSE	CCC, CE, CSA, cURus, SEMKO, VDE	CCC, CE, CSA, cURus, IMQ, SEMKO, VDE

Engineering Selection Recommendations

The 5TT 2-R is the primary direct substitute, maintaining identical electrical characteristics (100A breaking capacity, 29.9 melting I²t) while offering active product status and ROHS3 compliance. This part is recommended for applications requiring minimal design modification and direct functional replacement.

The 5ET 2-R provides enhanced breaking capacity (150A) and expanded certification coverage (CCC, cURus, SEMKO, VDE addition). Selection of this part is appropriate for applications requiring higher fault current withstand capability or broader international compliance requirements.

The 5ST 2-R offers the lowest DC cold resistance (0.03 Ohms) and most extensive certification portfolio (IMQ addition). This part is suitable for applications prioritizing minimal resistive losses or requiring the broadest regulatory approval scope. Breaking capacity is reduced to 35A, requiring verification against circuit fault current levels.

All substitute parts maintain RoHS3 compliance, addressing environmental regulatory requirements absent in the obsolete 5TT 2.

Frequently Asked Questions (FAQ)

Q: Can 5TT 2-R, 5ET 2-R, and 5ST 2-R be used interchangeably in 5TT 2 applications?

A: All three substitutes maintain the mandatory parameters for interchangeability: 2A current rating, 250VAC voltage rating, 5mm x 20mm physical dimensions, slow-blow response, and -55°C to 125°C operating range. Selection depends on breaking capacity requirements and certification needs specific to the application circuit.

Q: What is the significance of breaking capacity differences among substitutes?

A: Breaking capacity defines the maximum fault current a fuse can safely interrupt. The 5TT 2 and 5TT 2-R are rated at 100A, the 5ET 2-R at 150A, and the 5ST 2-R at 35A. Applications must verify that the selected substitute's breaking capacity exceeds the maximum available fault current in the protected circuit.

Q: How do melting I²t values affect substitute selection?

A: Melting I²t represents the thermal energy required to melt the fuse element. The 5TT 2 specifies 30, while substitutes range from 12 (5ST 2-R) to 92 (5ET 2-R). Lower I²t values provide faster response to overcurrent; higher values allow greater transient tolerance. Circuit protection coordination requirements determine the appropriate value.

Q: Are all substitutes compatible with existing 5mm x 20mm fuse holders?

A: Yes. All substitute parts maintain the 5mm x 20mm physical dimensions and cartridge glass construction, ensuring mechanical compatibility with standard holders designed for the 5TT 2.

Q: What compliance advantage do the substitute parts offer over the obsolete 5TT 2?

A: All active substitutes (5TT 2-R, 5ET 2-R, 5ST 2-R) are ROHS3 compliant, addressing environmental regulations. The 5ET 2-R and 5ST 2-R provide expanded international certifications (CCC, cURus, SEMKO, VDE), supporting broader market applications.

Q: How does DC cold resistance impact circuit performance?

A: DC cold resistance affects voltage drop across the fuse during normal operation. Lower resistance (5ST 2-R at 0.03 Ohms) minimizes power dissipation; higher resistance (5TT 2 at 0.09 Ohms) increases heat generation. Selection should consider thermal management and voltage drop budgets in the protected circuit.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message