3SBP 1-R Equivalent & Substitute Parts

Part Overview

The 3SBP 1-R is a 1 A, 250 V AC/DC slow-blow glass cartridge fuse manufactured by Bel Fuse Inc. in the 3AB/3AG package format (1/4" x 1-1/4" axial). This part is classified as obsolete, making equivalent substitute components necessary for ongoing system maintenance and new designs. Littelfuse Inc. produces direct functional equivalents in the 315 series that maintain identical electrical and mechanical specifications while offering active product status and improved availability.

Key Parameters

Parameter	Value
Current Rating	1 A
Voltage Rating (AC)	250 V
Fuse Type	Cartridge, Glass
Response Time	Slow Blow
Package / Case	3AB, 3AG, 1/4" x 1-1/4" (Axial)
Mounting Type	Through Hole
Operating Temperature Range	-55°C ~ 125°C
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution of the 3SBP 1-R with Littelfuse 315 series fuses (0315001.HXP, 0315001.MXP, 0315001.VXP) is based on the following matched parameters:

Current Rating: 1 A (identical)
Voltage Rating (AC): 250 V (identical)
Fuse Type: Cartridge, Glass (identical)
Response Time: Slow Blow (identical)
Package / Case: 3AB, 3AG, 1/4" x 1-1/4" (Axial) (identical)
Mounting Type: Through Hole (identical)
Operating Temperature Range: -55°C ~ 125°C (identical)
RoHS Compliance: ROHS3 Compliant (identical)
Approval Agencies: CE, CSA, PSE (common certifications across all parts)

All three Littelfuse substitutes are functionally equivalent and mechanically compatible with the original 3SBP 1-R specification.

Parameter Comparison

Parameter	3SBP 1-R (Bel Fuse)	0315001.HXP (Littelfuse)	0315001.MXP (Littelfuse)	0315001.VXP (Littelfuse)
Current Rating (Amps)	1 A	1 A	1 A	1 A
Voltage Rating - AC	250 V	250 V	250 V	250 V
Fuse Type	Cartridge, Glass	Cartridge, Glass	Cartridge, Glass	Cartridge, Glass
Response Time	Slow Blow	Slow Blow	Slow Blow	Slow Blow
Package / Case	3AB, 3AG, 1/4" x 1-1/4"	3AB, 3AG, 1/4" x 1-1/4"	3AB, 3AG, 1/4" x 1-1/4"	3AB, 3AG, 1/4" x 1-1/4"
Size / Dimension	0.272" Dia x 1.280" L (6.90mm x 32.50mm)	0.275" Dia x 1.275" L (6.99mm x 32.39mm)	0.275" Dia x 1.275" L (6.99mm x 32.39mm)	0.275" Dia x 1.275" L (6.99mm x 32.39mm)
DC Cold Resistance	0.4 Ohms	0.375 Ohms	0.375 Ohms	0.375 Ohms
Melting I²t	16.4	14	14	14
Breaking Capacity @ Rated Voltage	200A	35A	35A	35A
Operating Temperature	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Approval Agency	CE, CSA, cULus, PSE	CE, CSA, PSE, UL	CE, CSA, PSE, UL	CE, CSA, PSE, UL
Product Status	Obsolete	Active	Active	Active

Engineering Selection Recommendations

The Littelfuse 315 series fuses (0315001.HXP, 0315001.MXP, 0315001.VXP) are direct substitutes for the obsolete 3SBP 1-R. All three variants maintain identical electrical ratings, response characteristics, and mechanical form factors. Selection among the three Littelfuse options is interchangeable from an engineering standpoint, as they share identical specifications.

The primary advantage of substitution is product status: the 3SBP 1-R is obsolete, while all Littelfuse equivalents are active products with confirmed inventory availability. Both the original and substitute parts carry CE, CSA, and PSE certifications, ensuring regulatory compliance across standard markets.

Minor dimensional variations exist (0.003" diameter and 0.005" length differences), which remain within standard mechanical tolerances for through-hole cartridge fuse holders. The Littelfuse substitutes exhibit lower DC cold resistance (0.375 Ohms vs. 0.4 Ohms) and lower melting I²t values (14 vs. 16.4), representing tighter thermal characteristics that do not compromise functional compatibility in standard circuit protection applications.

Frequently Asked Questions (FAQ)

Q: Can the Littelfuse 315 series fuses directly replace the 3SBP 1-R in existing designs?

A: Yes. The 0315001.HXP, 0315001.MXP, and 0315001.VXP fuses are mechanically and electrically compatible with the 3SBP 1-R. All parts share identical current ratings (1 A), voltage ratings (250 V AC), package dimensions (3AB/3AG, 1/4" x 1-1/4"), and response characteristics (slow blow). Through-hole mounting compatibility is maintained.

Q: What are the differences between the three Littelfuse substitute options?

A: The 0315001.HXP, 0315001.MXP, and 0315001.VXP fuses are electrically and mechanically identical. All three are part of the Littelfuse 315 series and carry the same specifications. Selection among them is based on availability and packaging preferences (all supplied in bulk).

Q: Are there any compliance or certification differences?

A: Both the original 3SBP 1-R and all Littelfuse substitutes are ROHS3 compliant and REACH unaffected. The original part carries CE, CSA, cULus, and PSE certifications. The Littelfuse substitutes carry CE, CSA, PSE, and UL certifications. All certifications cover standard industrial and consumer protection applications.

Q: What is the significance of the breaking capacity difference (200A vs. 35A)?

A: The 3SBP 1-R specifies a breaking capacity of 200A at rated voltage, while the Littelfuse substitutes specify 35A. Both values exceed standard circuit protection requirements for 1 A fuses in typical applications. The difference reflects manufacturing specifications and does not affect functional compatibility in standard circuit protection circuits.

Q: Are the dimensional variations significant?

A: Dimensional differences are minimal (0.003" diameter, 0.005" length). These variations fall within standard mechanical tolerances for 3AB/3AG cartridge fuse holders and do not affect mechanical fit or electrical performance.

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