Equivalent & Substitute Parts for 5TTP 1.25-R

Part Overview

The 5TTP 1.25-R is a 1.25 A, 250 V AC/DC slow-blow glass cartridge fuse manufactured by Bel Fuse Inc. in a 5mm x 20mm axial through-hole package. This component is active in production and widely used in power distribution and circuit protection applications. Equivalent and substitute parts are identified to support procurement flexibility, inventory management, and supply chain continuity.

Substiute Parts

5TTP 1.25-R

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

Current PartRFQ

5ETP 1.25-R

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

Parametric EquivalentRFQ

02391.25MXEP

Littelfuse Inc.In Stock: 315602391.25MXEP Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 5TTP 1.25-R is determined by the following critical parameters:

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

All identified substitute parts meet these core electrical and mechanical parameters. Variations in secondary characteristics such as breaking capacity, melting I²t, DC cold resistance, and approval agency certifications do not preclude substitution when the primary parameters align.

Parameter Comparison

Engineering Selection Recommendations

All three parts are active products with ROHS3 compliance and meet the core electrical and mechanical specifications for direct substitution in applications requiring a 1.25 A, 250 V AC/DC slow-blow glass cartridge fuse in a 5mm x 20mm through-hole package.

The 5ETP 1.25-R (Bel Fuse) offers higher breaking capacity (150 A versus 100 A) and lower DC cold resistance (0.08 Ohms versus 0.206 Ohms), which may provide performance advantages in applications with higher fault current requirements or where resistance characteristics are critical.

The 02391.25MXEP (Littelfuse) provides an alternative from a different manufacturer with equivalent breaking capacity to the 5TTP 1.25-R and intermediate melting I²t characteristics. Approval agency certifications differ across the three parts; selection should align with regional compliance requirements (CE, CSA, cULus, PSE, UL, VDE, CCC, KC, SEMKO).

Frequently Asked Questions (FAQ)

Q: Can the 5ETP 1.25-R be used as a direct replacement for the 5TTP 1.25-R?

A: Yes. Both parts share identical current rating (1.25 A), voltage rating (250 V AC), fuse type (cartridge, glass), response time (slow blow), package dimensions (5mm x 20mm axial), and mounting type (through hole). The 5ETP 1.25-R has higher breaking capacity and lower DC cold resistance, which do not prevent substitution.

Q: What is the difference between the 5TTP 1.25-R and 02391.25MXEP in terms of physical dimensions?

A: The 5TTP 1.25-R measures 0.217" Dia x 0.827" L (5.50mm x 21.00mm). The 02391.25MXEP measures 0.217" Dia x 0.846" L (5.50mm x 21.50mm). The length difference is 0.5mm, which may affect fit in space-constrained applications. Verify mechanical clearance before substitution.

Q: Are there differences in approval agency certifications among these three parts?

A: Yes. The 5TTP 1.25-R carries CE, CSA, cULus, and PSE approvals. The 5ETP 1.25-R carries CCC, CE, CSA, cULus, SEMKO, and VDE approvals. The 02391.25MXEP carries CE, CSA, KC, PSE, and UL approvals. Select the part whose certifications align with your regional and application requirements.

Q: What does melting I²t indicate, and why does it vary among these parts?

A: Melting I²t is a measure of the thermal energy required to melt the fuse element. The 5TTP 1.25-R has a melting I²t of 13.1, the 5ETP 1.25-R has 42, and the 02391.25MXEP has 19.525. These variations reflect differences in fuse element design and material composition. All three parts are rated for the same current and voltage, so substitution is valid from an electrical protection standpoint.

Q: Can these parts be used interchangeably in all applications?

A: These parts are electrically and mechanically equivalent for applications requiring 1.25 A, 250 V AC/DC slow-blow protection in a 5mm x 20mm through-hole package. However, verify that the specific approval certifications required by your application and region are present on the selected part. Additionally, confirm mechanical fit, particularly the 0.5mm length difference between the 5TTP 1.25-R and 02391.25MXEP.