5SFP 3.15 Glass Cartridge Fuse Equivalent & Substitute Parts

Part Overview

The 5SFP 3.15 is a 3.15 A, 250 V AC/DC fast-blow glass cartridge fuse in 5mm x 20mm axial package manufactured by Bel Fuse Inc. This part is classified as obsolete, making equivalent substitute parts necessary for ongoing system maintenance and new design implementations. Substitute parts must maintain identical electrical ratings, mechanical dimensions, and functional characteristics to ensure direct compatibility in through-hole fuse applications.

Key Parameters

Parameter	Value
Current Rating	3.15 A
Voltage Rating (AC)	250 V
Fuse Type	Cartridge, Glass
Response Time	Fast Blow
Package / Case	5mm x 20mm (Axial)
Mounting Type	Through Hole
Breaking Capacity @ Rated Voltage	35 A
Melting I²t	16
Operating Temperature Range	-55°C ~ 125°C

Substitute Part Grouping Explanation

Substitute parts for the 5SFP 3.15 are qualified based on strict equivalence of the following parameters:

Current Rating: 3.15 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)
Package / Case: 5mm x 20mm (Axial) (exact match required)
Mounting Type: Through Hole (exact match required)
Breaking Capacity: 35 A (exact match required)
Melting I²t: 16 ± tolerance (within acceptable range)

All substitute parts listed below meet these criteria and are direct functional equivalents suitable for replacement in applications originally designed for the 5SFP 3.15.

Parameter Comparison

Parameter	5SFP 3.15	5SFP 3.15-R	0034.1521.PT	02173.15MXEP
Manufacturer	Bel Fuse Inc.	Bel Fuse Inc.	SCHURTER Inc.	Littelfuse Inc.
Current Rating (Amps)	3.15 A	3.15 A	3.15 A	3.15 A
Voltage Rating - AC	250 V	250 V	250 V	250 V
Fuse Type	Cartridge, Glass	Cartridge, Glass	Cartridge, Glass	Cartridge, Glass
Response Time	Fast Blow	Fast Blow	Fast Blow	Fast Blow
Package / Case	5mm x 20mm (Axial)	5mm x 20mm (Axial)	5mm x 20mm (Axial)	5mm x 20mm (Axial)
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole
Breaking Capacity @ Rated Voltage	35 A	35 A	35 A	35 A
Melting I²t	16	16	16.1	17.72
Operating Temperature	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C
Product Status	Obsolete	Active	Active	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

The 5SFP 3.15-R is the primary substitute, manufactured by the same supplier (Bel Fuse Inc.) with identical electrical and mechanical specifications. This part is active in production and ROHS3 compliant, addressing the obsolescence of the original 5SFP 3.15.

The 0034.1521.PT (SCHURTER Inc.) and 02173.15MXEP (Littelfuse Inc.) are functionally equivalent alternatives. Both are active products with ROHS3 compliance. The 02173.15MXEP carries broader international certifications (BSI, CE, CCC, CSA, KC, PSE, SEMKO, UR, VDE) compared to the 0034.1521.PT (cURus only). Selection between these alternatives depends on supply chain requirements, certification scope needed for the application, and inventory availability.

All three substitute parts maintain the critical electrical parameters (3.15 A, 250 V, 35 A breaking capacity, fast-blow response) and mechanical compatibility (5mm x 20mm through-hole package) required for direct replacement.

Frequently Asked Questions (FAQ)

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

A: Yes. The 5SFP 3.15-R is electrically and mechanically identical to the 5SFP 3.15, with the same current rating (3.15 A), voltage rating (250 V), package dimensions (5mm x 20mm), and fast-blow response time. The primary difference is product status (active vs. obsolete) and RoHS compliance.

Q: What is the significance of the Melting I²t values differing between substitutes?

A: The Melting I²t parameter indicates the thermal energy required to melt the fuse element. The 5SFP 3.15 specifies 16, while the 0034.1521.PT is 16.1 and the 02173.15MXEP is 17.72. These variations remain within acceptable tolerance for fast-blow cartridge fuses at this current rating and do not affect functional compatibility in standard applications.

Q: Are there dimensional differences between substitute parts?

A: Minor dimensional variations exist. The 5SFP 3.15 and 5SFP 3.15-R are 0.217" diameter x 0.827" length. The 0034.1521.PT is 0.213" diameter x 0.886" length, and the 02173.15MXEP is 0.228" diameter x 0.886" length. These variations are within standard tolerance for 5mm x 20mm axial cartridge fuses and do not prevent mechanical fit in standard through-hole fuse holders.

Q: Which substitute part should be selected for new designs?

A: For new designs, select from the active products: 5SFP 3.15-R (Bel Fuse Inc.), 0034.1521.PT (SCHURTER Inc.), or 02173.15MXEP (Littelfuse Inc.). All are ROHS3 compliant. If specific international certifications are required, the 02173.15MXEP offers the broadest certification scope (BSI, CE, CCC, CSA, KC, PSE, SEMKO, UR, VDE).

Q: What is the DC Cold Resistance difference between parts?

A: The 5SFP 3.15 specifies 0.025 Ohms, the 5SFP 3.15-R specifies 0.22 Ohms, and the 02173.15MXEP specifies 0.0224 Ohms. These minor variations do not affect fuse operation in standard circuit protection applications.

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