Equivalent & Substitute Parts for 5HT 1.25

Part Overview

The 5HT 1.25 is a ceramic cartridge fuse manufactured by Bel Fuse Inc., rated for 1.25 A at 250 V AC with slow-blow response characteristics. This component is classified as obsolete, which necessitates identification of active equivalent alternatives for ongoing system support and new designs. The fuse is designed for 5mm x 20mm holder-based installations and meets multiple international safety certifications including UL, CE, VDE, and CSA standards.

Substiute Parts

5HT 1.25

Bel Fuse Inc.In Stock: 8955HT 1.25 Datasheet

Current PartRFQ

5HT 1.25-R

Bel Fuse Inc.In Stock: 46945HT 1.25-R Datasheet

DirectRFQ

0001.2505

SCHURTER Inc.In Stock: 122240001.2505 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 5HT 1.25 is determined by strict equivalence across the following critical parameters:

• Current Rating: 1.25 A (exact match required)
• Voltage Rating (AC): 250 V (minimum requirement)
• Fuse Type: Cartridge, Ceramic
• Response Time: Slow Blow
• Physical Package: 5mm x 20mm
• Breaking Capacity: 1.5 kA @ Rated Voltage
• Mounting Configuration: Requires Holder

Two active substitute parts meet these criteria: the 5HT 1.25-R from Bel Fuse Inc. and the 0001.2505 from SCHURTER Inc. Both maintain identical current and AC voltage ratings, ceramic construction, slow-blow characteristics, and physical dimensions. The 0001.2505 provides additional DC voltage capability (300 V DC) beyond the AC specification, which does not compromise compatibility in AC-rated applications.

Parameter Comparison

Engineering Selection Recommendations

The 5HT 1.25-R from Bel Fuse Inc. is the primary substitute for the obsolete 5HT 1.25. Both parts are manufactured by the same supplier, share identical electrical and mechanical specifications, and maintain the same series designation. The 5HT 1.25-R is currently in active production with significantly higher inventory availability (4,621 units in stock versus 856 units for the obsolete part). This part achieves ROHS3 compliance, addressing regulatory requirements for new designs.

The 0001.2505 from SCHURTER Inc. serves as a secondary substitute option. It maintains all critical electrical parameters and physical dimensions required for direct mechanical and electrical compatibility. The SCHURTER part offers extended DC voltage capability (300 V DC) and is also ROHS3 compliant. The melting I²t value of 1.86 differs from the primary part specification of 3, reflecting a slightly faster thermal response within the slow-blow classification. This part is available in high volume (12,134 units in stock).

Both substitute parts carry equivalent international safety certifications (CCC, VDE, PSE, cURus) appropriate for the application domain. Selection between the two substitutes should be based on supply chain preference, inventory availability, and any specific DC voltage requirements in the application circuit.

Frequently Asked Questions (FAQ)

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

A: Yes. The 5HT 1.25-R maintains identical current rating (1.25 A), AC voltage rating (250 V), fuse type (ceramic cartridge), response time (slow blow), physical dimensions (5mm x 20mm), and breaking capacity (1.5 kA). Both parts require the same holder configuration and operate across the same temperature range (-55°C to 125°C).

Q: What is the difference between the Bel Fuse and SCHURTER substitutes?

A: Both parts meet the core electrical and mechanical requirements. The primary differences are: (1) manufacturer source, (2) melting I²t value (3 for Bel Fuse versus 1.86 for SCHURTER), and (3) DC voltage rating (not specified for Bel Fuse versus 300 V for SCHURTER). The SCHURTER part provides additional DC voltage capability without compromising AC performance.

Q: Are there any compliance differences between the main part and substitutes?

A: Yes. The obsolete 5HT 1.25 is RoHS non-compliant. Both active substitutes (5HT 1.25-R and 0001.2505) are ROHS3 compliant, meeting current environmental and regulatory standards for new equipment designs and manufacturing.

Q: Do these fuses require specific holder hardware?

A: Yes. All three parts (5HT 1.25, 5HT 1.25-R, and 0001.2505) are cartridge-type fuses that require a 5mm x 20mm fuse holder for installation. The physical dimensions are compatible across all three parts, ensuring mechanical interchangeability within existing holder assemblies.

Q: Which substitute should be selected for new designs?

A: For new designs, either the 5HT 1.25-R or 0001.2505 is acceptable based on the electrical requirements and supply chain considerations. Both are active products with ROHS3 compliance. If DC voltage capability is required in the circuit, the 0001.2505 (300 V DC rating) provides additional margin. If maintaining the same manufacturer source is preferred, the 5HT 1.25-R is the direct equivalent.