5MFP 4 Equivalent & Substitute Parts

Part Overview

The 5MFP 4 is a 4A 125VAC fast-blow glass cartridge fuse with a 5mm x 20mm axial form factor, manufactured by Bel Fuse Inc. This component is classified as obsolete, making identification of suitable substitutes essential for ongoing system maintenance and component sourcing. The 5MFP 4-R represents the active production equivalent within the same product series, offering functional compatibility with improved compliance status.

Substiute Parts

5MFP 4

Bel Fuse Inc.In Stock: 8795MFP 4 Datasheet

Current PartRFQ

5MFP 4-R

Bel Fuse Inc.In Stock: 17855MFP 4-R Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

The 5MFP 4-R qualifies as a direct substitute for the 5MFP 4 based on the following critical parameters:

• Current Rating: Identical at 4 A
• Voltage Rating (AC): Identical at 125 V
• Fuse Type: Both are cartridge glass fast-blow fuses
• Package / Case: Identical 5mm x 20mm axial form factor
• Breaking Capacity: Identical at 10kA
• Melting I²t: Identical at 22
• Operating Temperature Range: Identical -55°C ~ 125°C
• Mounting Type: Both through-hole

The substitution is based on electrical and mechanical parameter equivalence. The 5MFP 4-R maintains all functional specifications required for direct replacement in circuits designed for the 5MFP 4.

Parameter Comparison

Engineering Selection Recommendations

The 5MFP 4-R is the appropriate substitute for the obsolete 5MFP 4. Selection is based on:

• Electrical equivalence across all critical parameters (current, voltage, breaking capacity, melting I²t)
• Mechanical compatibility (identical form factor and mounting type)
• Active product status ensuring ongoing availability
• Enhanced RoHS3 compliance of the substitute part
• Maintained approval certifications (CE, CSA, PSE)

For applications requiring the full original certification set (including UL), verification against specific system requirements is necessary, as the 5MFP 4-R does not list UL approval.

Frequently Asked Questions (FAQ)

Q: Can the 5MFP 4-R be used as a direct replacement for the 5MFP 4?

A: Yes. The 5MFP 4-R is electrically and mechanically equivalent. Both parts share identical current rating (4A), voltage rating (125VAC), fuse type (cartridge glass fast-blow), package dimensions (5mm x 20mm axial), breaking capacity (10kA), and melting I²t (22).

Q: What is the primary difference between these two parts?

A: The 5MFP 4 is obsolete, while the 5MFP 4-R is active production. The 5MFP 4-R also offers improved RoHS3 compliance. DC cold resistance differs slightly (0.021 Ohms vs. 0.022 Ohms), which is within normal manufacturing tolerance and does not affect functional performance.

Q: Are there any certification differences I should be aware of?

A: The 5MFP 4 carries CE, CSA, PSE, and UL approvals. The 5MFP 4-R carries CE, CSA, and PSE approvals. If UL certification is a system requirement, this difference must be evaluated against your application specifications.

Q: Will the 5MFP 4-R fit in the same socket or holder as the 5MFP 4?

A: Yes. Both parts have identical dimensions (0.217" diameter x 0.827" length / 5.50mm x 21.00mm) and axial through-hole mounting, ensuring mechanical compatibility with existing component holders and PCB layouts.

Q: Is there any performance difference between these fuses?

A: No. Both parts have identical electrical performance characteristics: 4A current rating, 125V AC voltage rating, fast-blow response time, 10kA breaking capacity, and 22 melting I²t value. Operating temperature range is also identical (-55°C to 125°C).