5MF 4 Equivalent & Substitute Parts Reference

Part Overview

The 5MF 4 is a 4A 125VAC fast-blow glass cartridge fuse manufactured by Bel Fuse Inc., designed for 5mm x 20mm holder applications. This part is classified as obsolete, making equivalent substitutes necessary for ongoing system maintenance and new designs. The fuse provides circuit protection with a 10kA breaking capacity and operates across a temperature range of -55°C to 125°C. Substitute parts must maintain identical electrical ratings, mechanical dimensions, and approval certifications to ensure direct compatibility.

Substiute Parts

5MF 4

Bel Fuse Inc.In Stock: 10615MF 4 Datasheet

Current PartRFQ

5MF 4-R

Bel Fuse Inc.In Stock: 36435MF 4-R Datasheet

DirectRFQ

0235004.HXP

Littelfuse Inc.In Stock: 12320235004.HXP Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution for the 5MF 4 is determined by strict equivalence across the following critical parameters:

Electrical Equivalence: Current rating (4 A), voltage rating (125 V AC), and response time (fast blow) must be identical. Breaking capacity must meet or exceed 10kA at rated voltage.

Mechanical Equivalence: Package dimensions must be 5mm x 20mm to ensure compatibility with existing fuse holders. Cartridge glass fuse type is mandatory.

Regulatory Equivalence: Substitute parts must carry approval from at least the same regulatory agencies (CE, CSA, PSE, UL) to maintain system compliance.

Product Status Consideration: While the main part is obsolete, active substitute parts ensure continued availability and support for legacy system maintenance.

Two substitute parts meet these criteria: the 5MF 4-R (direct manufacturer equivalent from Bel Fuse Inc.) and the 0235004.HXP (cross-manufacturer equivalent from Littelfuse Inc.).

Parameter Comparison

Engineering Selection Recommendations

5MF 4-R (Bel Fuse Inc.): This is the direct manufacturer equivalent and the primary substitute for the 5MF 4. It maintains identical electrical and mechanical specifications while offering active product status and ROHS3 compliance. The 5MF 4-R carries regulatory approvals including cULus certification and is recommended for applications requiring continuity with the original Bel Fuse product line.

0235004.HXP (Littelfuse Inc.): This cross-manufacturer substitute provides full electrical and mechanical equivalence with additional regulatory certifications (KC approval). It is suitable for applications where cross-manufacturer sourcing is acceptable and offers ROHS3 compliance. The 0235004.HXP is recommended when supply chain diversification or Littelfuse product line integration is required.

Both substitutes are active products with current inventory availability, making them suitable for immediate deployment in legacy system maintenance and new designs requiring 4A 125VAC fast-blow fuse protection in 5mm x 20mm form factors.

Frequently Asked Questions (FAQ)

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

A: Yes. The 5MF 4-R is electrically and mechanically identical to the 5MF 4, with identical current rating (4 A), voltage rating (125 V AC), response time (fast blow), and package dimensions (5mm x 20mm). Both require the same fuse holder and provide 10kA breaking capacity.

Q: What is the difference between the 5MF 4-R and 0235004.HXP?

A: Both parts are electrically and mechanically equivalent. The primary differences are manufacturer (Bel Fuse Inc. vs. Littelfuse Inc.) and regulatory certifications. The 0235004.HXP includes KC approval in addition to CE, CSA, PSE, and UL certifications. Both are ROHS3 compliant and active products.

Q: Why is the main part (5MF 4) marked as obsolete?

A: The 5MF 4 is classified as obsolete by the manufacturer, indicating it is no longer in active production. The 5MF 4-R serves as the active replacement from the same manufacturer, maintaining full compatibility while offering improved compliance status.

Q: Are there any dimensional differences between these fuses?

A: The 5MF 4 and 5MF 4-R have identical dimensions (5.10mm x 20.00mm). The 0235004.HXP has a slightly larger diameter (5.20mm) but maintains the same 20.00mm length. All three fit standard 5mm x 20mm fuse holders.

Q: Can I mix these fuses in the same circuit board or equipment?

A: Yes, all three fuses are mechanically and electrically interchangeable within the same fuse holder. They provide identical circuit protection characteristics and can be used interchangeably in applications requiring 4A 125VAC fast-blow protection.

Q: Which substitute should I choose for new designs?

A: For new designs, either the 5MF 4-R or 0235004.HXP is appropriate. The 5MF 4-R is recommended if maintaining a single-manufacturer product line is preferred. The 0235004.HXP is recommended if cross-manufacturer sourcing or additional regulatory certifications (KC) are required.