Equivalent & Substitute Parts for 5STP 1.25

Part Overview

The 5STP 1.25 is a 1.25 A, 250 V AC/DC slow-blow glass cartridge fuse with a 5mm x 20mm axial form factor, manufactured by Bel Fuse Inc. This part is classified as obsolete. Due to its obsolete status, identifying equivalent and substitute parts is necessary to maintain design continuity and ensure component availability for ongoing production, maintenance, and repair applications. Active alternatives with identical or compatible electrical and mechanical specifications are available from multiple manufacturers.

Substiute Parts

5STP 1.25

Bel Fuse Inc.In Stock: 8355STP 1.25 Datasheet

Current PartRFQ

5STP 1.25-R

Bel Fuse Inc.In Stock: 10845STP 1.25-R Datasheet

DirectRFQ

5ETP 1.25-R

Bel Fuse Inc.In Stock: 21195ETP 1.25-R Datasheet

Parametric EquivalentRFQ

5TTP 1.25-R

Bel Fuse Inc.In Stock: 17625TTP 1.25-R Datasheet

Parametric EquivalentRFQ

0034.3118.PT

SCHURTER Inc.In Stock: 38580034.3118.PT Datasheet

DirectRFQ

02181.25MXEP

Littelfuse Inc.In Stock: 72802181.25MXEP Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 5STP 1.25 is determined by strict alignment with the following parameters:

• Current Rating: 1.25 A (exact match required)
• Voltage Rating (AC): 250 V (exact match required)
• Response Time: Slow Blow (exact match required)
• Package / Case: 5mm x 20mm (Axial) (exact match required)
• Fuse Type: Cartridge, Glass (exact match required)
• Mounting Type: Through Hole (exact match required)
• Operating Temperature Range: -55°C ~ 125°C (exact match required)

All substitute parts listed below meet these core electrical and mechanical criteria. Variations in breaking capacity, melting I²t, DC cold resistance, and approval agencies are noted but do not disqualify substitution when the primary parameters align.

Parameter Comparison

Engineering Selection Recommendations

5STP 1.25-R (Bel Fuse Inc.) is the direct active equivalent. It maintains identical electrical characteristics and mechanical form factor to the obsolete 5STP 1.25, with the addition of ROHS3 compliance. This part is recommended as the primary replacement for direct substitution in new designs and legacy system updates.

5ETP 1.25-R and 5TTP 1.25-R (Bel Fuse Inc.) are parametric equivalents from the same manufacturer. Both are active and ROHS3 compliant. These parts differ in breaking capacity and melting I²t characteristics. Selection between these variants depends on circuit protection requirements beyond the core 1.25 A, 250 V specification.

0034.3118.PT (SCHURTER Inc.) is an active direct equivalent with identical breaking capacity (35 A) to the original part. Physical dimensions show minor variation (5.40mm x 22.50mm versus 5.50mm x 21.00mm). This part carries cURus approval and ROHS3 compliance.

02181.25MXEP (Littelfuse Inc.) is an active direct equivalent with the broadest approval agency coverage, including CCC, CE, CSA, K-MARK, PSE, SEMKO, UL, and VDE. Physical dimensions are 5.80mm x 22.50mm. This part is suitable for applications requiring extensive international certifications.

All substitute parts are active products with current manufacturing status and ROHS3 compliance, ensuring long-term availability and regulatory alignment.

Frequently Asked Questions (FAQ)

Q: Can I use 5ETP 1.25-R or 5TTP 1.25-R as direct replacements for 5STP 1.25?

A: Yes. Both parts meet all core electrical and mechanical parameters: 1.25 A current rating, 250 V AC voltage rating, slow-blow response, and 5mm x 20mm axial package. They differ in breaking capacity and melting I²t, which may affect circuit protection behavior under fault conditions. Verify that these differences are acceptable for your specific application.

Q: What is the difference between 5STP 1.25-R and 5ETP 1.25-R?

A: Both are 1.25 A, 250 V slow-blow fuses in identical packages. The 5ETP 1.25-R has higher breaking capacity (150 A versus 35 A) and higher melting I²t (42 versus 4.1). The 5STP 1.25-R maintains the original electrical characteristics of the obsolete 5STP 1.25.

Q: Are there physical dimension differences between substitute parts?

A: Minor variations exist. The original 5STP 1.25 and 5STP 1.25-R are 5.50mm x 21.00mm. The SCHURTER 0034.3118.PT is 5.40mm x 22.50mm. The Littelfuse 02181.25MXEP is 5.80mm x 22.50mm. These variations are within typical fuse holder tolerances but should be verified for your specific socket or holder design.

Q: Which substitute part has the broadest international certification coverage?

A: The Littelfuse 02181.25MXEP carries the most extensive approval agency list: CCC, CE, CSA, K-MARK, PSE, SEMKO, UL, and VDE. This part is recommended for applications requiring compliance across multiple international markets.

Q: Is the obsolete 5STP 1.25 still available?

A: The 5STP 1.25 is classified as obsolete but remains in inventory (765 pcs). However, the active 5STP 1.25-R is the recommended replacement for new designs and ongoing production to ensure long-term supply continuity.