Equivalent & Substitute Parts for 5MFP 1.25

Part Overview

The 5MFP 1.25 is a 1.25 A, 250 V AC/DC fast-blow glass cartridge fuse with a 5mm x 20mm axial form factor, manufactured by Bel Fuse Inc. This part is classified as obsolete, making identification of equivalent and substitute components essential for ongoing system support and procurement planning. The fuse is designed for through-hole mounting applications requiring fast-response overcurrent protection in industrial and commercial equipment.

Substiute Parts

5MFP 1.25

Bel Fuse Inc.In Stock: 11055MFP 1.25 Datasheet

Current PartRFQ

5MFP 1.25-R

Bel Fuse Inc.In Stock: 19475MFP 1.25-R Datasheet

DirectRFQ

5SFP 1.25-R

Bel Fuse Inc.In Stock: 17595SFP 1.25-R Datasheet

Parametric EquivalentRFQ

02171.25MXEP

Littelfuse Inc.In Stock: 142602171.25MXEP Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 5MFP 1.25 is determined by the following critical parameters:

• Current Rating: 1.25 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)
• Operating Temperature Range: -55°C ~ 125°C (minimum requirement)

All identified substitute parts meet these core electrical and mechanical parameters. Variations in breaking capacity, melting I²t, DC cold resistance, and approval agencies are permitted within the scope of substitution, provided the primary protective characteristics remain functionally equivalent.

Parameter Comparison

Engineering Selection Recommendations

5MFP 1.25-R (Direct Manufacturer Equivalent)

The 5MFP 1.25-R is the primary substitute for the obsolete 5MFP 1.25. Both parts are manufactured by Bel Fuse Inc. and share identical electrical and mechanical specifications, including current rating, voltage rating, breaking capacity, and melting I²t. The 5MFP 1.25-R is currently in active production status with ROHS3 compliance, making it the preferred choice for new designs and direct replacement applications. Approval agencies include CE, CSA, cULus, and PSE.

5SFP 1.25-R (Parametric Equivalent)

The 5SFP 1.25-R is a parametric equivalent manufactured by Bel Fuse Inc. It maintains identical current, voltage, response time, and package specifications. The breaking capacity is reduced to 35 A, and melting I²t is increased to 2.5. This part is suitable for applications where the lower breaking capacity is acceptable. The 5SFP 1.25-R carries expanded approval certifications including CCC, CE, CSA, cULus, IMQ, SEMKO, and VDE, and is ROHS3 compliant.

02171.25MXEP (Cross-Manufacturer Equivalent)

The 02171.25MXEP, manufactured by Littelfuse Inc., is a cross-manufacturer equivalent meeting all core electrical and mechanical parameters. Breaking capacity is 35 A with melting I²t of 2.23. Physical dimensions are slightly larger (5.80mm x 22.50mm versus 5.50mm x 21.00mm), which must be verified for mechanical fit in the target application. This part carries comprehensive international approvals including BSI, CE, CCC, CSA, KC, PSE, SEMKO, UR, and VDE, and is ROHS3 compliant.

Frequently Asked Questions (FAQ)

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

A: Yes. The 5MFP 1.25-R is electrically and mechanically identical to the 5MFP 1.25, with the same current rating, voltage rating, breaking capacity, and melting I²t. The primary difference is product status (active versus obsolete) and improved RoHS compliance.

Q: What is the difference between the 5MFP 1.25-R and 5SFP 1.25-R?

A: Both parts share identical current, voltage, response time, and package specifications. The 5SFP 1.25-R has a lower breaking capacity (35 A versus 200 A) and higher melting I²t (2.5 versus 1.5). Selection depends on the application's breaking capacity requirement.

Q: Can the Littelfuse 02171.25MXEP be used in place of the Bel Fuse 5MFP 1.25?

A: The 02171.25MXEP meets all electrical specifications and is mechanically compatible with the 5mm x 20mm form factor. However, physical dimensions are slightly larger (5.80mm x 22.50mm). Mechanical fit in the target application must be verified before substitution.

Q: Are all substitute parts RoHS compliant?

A: The 5MFP 1.25 is RoHS non-compliant. All three substitute parts (5MFP 1.25-R, 5SFP 1.25-R, and 02171.25MXEP) are ROHS3 compliant.

Q: What approval agencies are common to all substitute parts?

A: CE and CSA certifications are present across all substitute parts. The 02171.25MXEP carries the broadest approval coverage, including BSI, CCC, KC, SEMKO, UR, and VDE in addition to CE and CSA.

Q: Does DC cold resistance variation affect substitution suitability?

A: DC cold resistance values range from 0.062 to 0.09 Ohms across the substitute parts. These variations are within acceptable tolerances for fast-blow fuse applications and do not preclude substitution based on this parameter alone.