Equivalent & Substitute Parts for 5ST 3.15 Glass Cartridge Fuse

Part Overview

The Bel Fuse Inc. 5ST 3.15 is a 3.15 A, 250 V AC/DC glass cartridge fuse with slow-blow response characteristics, designed for 5mm x 20mm holder mounting. This part is classified as obsolete. Equivalent and substitute parts are necessary to maintain circuit protection functionality in applications where the original 5ST 3.15 is no longer available or where active product alternatives offer improved compliance and availability.

Key Parameters

Parameter	Value
Current Rating	3.15 A
Voltage Rating (AC)	250 V
Fuse Type	Cartridge, Glass
Package / Case	5mm x 20mm
Response Time	Slow Blow
Mounting Type	Requires Holder
Operating Temperature Range	-55°C to 125°C

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict equivalence across the following parameters: current rating (3.15 A), voltage rating (250 V AC), fuse type (cartridge glass), package dimensions (5mm x 20mm), response time (slow blow), and mounting requirement (holder-based). Parts are grouped into two categories:

Direct Equivalents: Parts that match all critical electrical and mechanical parameters with identical breaking capacity and melting I²t characteristics, ensuring drop-in replacement capability.

Parametric Equivalents: Parts that maintain identical current, voltage, package, and response characteristics but differ in breaking capacity or melting I²t, requiring application-level verification of circuit protection requirements.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Current (A)	Voltage (V AC)	Response Time	Package	Breaking Capacity (A)	Melting I²t	Product Status	RoHS Status
5ST 3.15	Bel Fuse Inc.	3.15	250	Slow Blow	5mm x 20mm	35	33	Obsolete	Non-compliant
5ST 3.15-R	Bel Fuse Inc.	3.15	250	Slow Blow	5mm x 20mm	35	33	Active	ROHS3 Compliant
5ET 3.15-R	Bel Fuse Inc.	3.15	250	Slow Blow	5mm x 20mm	150	203	Active	ROHS3 Compliant
0034.3122	SCHURTER Inc.	3.15	250	Slow Blow	5mm x 20mm	35	47	Active	ROHS3 Compliant
02183.15MXBP	Littelfuse Inc.	3.15	250	Slow Blow	5mm x 20mm	35	38.15	Active	ROHS3 Compliant
02183.15MXP	Littelfuse Inc.	3.15	250	Slow Blow	5mm x 20mm	35	38.15	Active	ROHS3 Compliant
02183.15VXP	Littelfuse Inc.	3.15	250	Slow Blow	5mm x 20mm	35	38.15	Active	ROHS3 Compliant
02133.15HXP	Littelfuse Inc.	3.15	250	Slow Blow	5mm x 20mm	35	202	Active	ROHS3 Compliant
02133.15TXP	Littelfuse Inc.	3.15	250	Slow Blow	5mm x 20mm	35	202	Active	ROHS3 Compliant
02183.15HXP	Littelfuse Inc.	3.15	250	Slow Blow	5mm x 20mm	35	38.15	Active	ROHS3 Compliant
02183.15MXF18P	Littelfuse Inc.	3.15	250	Slow Blow	5mm x 20mm	35	38.15	Active	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation: 5ST 3.15-R (Bel Fuse Inc.) is the direct active equivalent to the obsolete 5ST 3.15, maintaining identical electrical and mechanical specifications with ROHS3 compliance and significantly higher inventory availability (53,252 units).

Alternative Direct Equivalents: Littelfuse 02183.15MXP, 02183.15MXBP, 02183.15VXP, and 02183.15HXP provide functionally equivalent performance with identical breaking capacity (35 A) and comparable melting I²t values (38.15). These parts carry broader international certifications including CCC, CE, CSA, K-MARK, PSE, SEMKO, UL, and VDE.

Parametric Equivalent: Bel Fuse Inc. 5ET 3.15-R maintains identical current, voltage, and package specifications but features higher breaking capacity (150 A) and melting I²t (203). This part is suitable for applications requiring enhanced fault current handling within the same form factor.

Cross-Manufacturer Option: SCHURTER 0034.3122 provides equivalent electrical performance with identical breaking capacity (35 A) and is ROHS3 compliant, though melting I²t is slightly elevated at 47.

All recommended substitutes are active products with ROHS3 compliance, addressing the non-compliance status of the original 5ST 3.15.

Frequently Asked Questions (FAQ)

Q: Can 5ST 3.15-R be used as a direct replacement for the obsolete 5ST 3.15?

A: Yes. The 5ST 3.15-R is the active equivalent with identical current rating (3.15 A), voltage rating (250 V AC), response time (slow blow), package dimensions (5mm x 20mm), and breaking capacity (35 A). It is a direct drop-in replacement.

Q: What is the difference between direct equivalents and parametric equivalents?

A: Direct equivalents match all critical electrical and mechanical parameters, including breaking capacity and melting I²t. Parametric equivalents maintain current, voltage, package, and response characteristics but differ in breaking capacity or melting I²t, requiring circuit-level analysis to confirm suitability.

Q: Why does the 5ET 3.15-R have a higher breaking capacity (150 A) than the original 5ST 3.15 (35 A)?

A: The 5ET series is designed for higher fault current environments. While it maintains the same current rating (3.15 A) and voltage (250 V), its enhanced breaking capacity provides protection in circuits with higher available short-circuit current. Application requirements determine whether this upgrade is necessary.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All active substitute parts listed are ROHS3 compliant, addressing the non-compliance status of the obsolete 5ST 3.15.

Q: Do all substitute parts fit the same 5mm x 20mm holder?

A: Yes. All substitute parts maintain the 5mm x 20mm package specification and are designed for the same holder mounting type. Physical compatibility is assured.

Q: Which substitute offers the highest inventory availability?

A: Littelfuse 02183.15MXP offers the highest inventory with 100,300 units in stock, followed by Bel Fuse 5ST 3.15-R with 53,252 units.

Q: What certifications should I prioritize when selecting a substitute?

A: Selection depends on application requirements. Littelfuse parts (02183.15MXP, 02183.15MXBP, 02183.15VXP, 02183.15HXP, 02183.15MXF18P) carry the broadest certification coverage including CCC, CE, CSA, K-MARK, PSE, SEMKO, UL, and VDE. Bel Fuse 5ST 3.15-R includes CCC, CE, CSA, cURus, IMQ, SEMKO, and VDE.

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