Bel Fuse Inc. 5MT 250 Glass Cartridge Fuse Equivalent & Substitute Parts

Part Overview

The Bel Fuse Inc. 5MT 250 is a 250 mA, 250 V AC/DC glass cartridge fuse with a 5mm x 20mm form factor. This component is classified as obsolete, necessitating identification of active equivalent alternatives for ongoing system maintenance and new designs. The fuse requires a dedicated holder for installation and operates across a temperature range of -55°C to 125°C with medium blow response characteristics.

Substiute Parts

5MT 250

Bel Fuse Inc.In Stock: 11315MT 250 Datasheet

Current PartRFQ

20102500001

Littelfuse Inc.In Stock: 72320102500001 Datasheet

SimilarRFQ

20102500021

Littelfuse Inc.In Stock: 105120102500021 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the 5MT 250 is determined by strict equivalence across the following critical parameters:

• Current Rating: 250 mA (exact match required)
• Voltage Rating: 250 V AC (exact match required)
• Fuse Type: Cartridge, Glass (exact match required)
• Package / Case: 5mm x 20mm (exact match required)
• Response Time: Medium Blow (exact match required)
• Mounting Type: Requires Holder (exact match required)

The substitute parts identified—Littelfuse Inc. 20102500001 and 20102500021—meet all critical electrical and mechanical parameters. Both are active products from an established manufacturer, providing direct functional equivalence to the obsolete 5MT 250.

Parameter Comparison

Engineering Selection Recommendations

Both Littelfuse 20102500001 and 20102500021 provide direct electrical and mechanical equivalence to the obsolete 5MT 250. Selection between these two substitute parts should be based on:

• Product Status: Both are active products with established supply chains, eliminating obsolescence risk.
• Compliance: Both substitute parts are ROHS3 compliant, whereas the original 5MT 250 is non-compliant. This represents an improvement for new designs and systems requiring RoHS compliance.
• Certifications: The substitute parts carry cULus approval. The original part carried CE, CSA, and cULus certifications. Verification of certification requirements for your specific application is necessary.
• Operating Temperature: The substitute parts operate within -25°C to 70°C, a narrower range than the original -55°C to 125°C. Applications requiring operation outside this range require evaluation.
• Breaking Capacity: Substitute parts provide 80 A breaking capacity versus 35 A for the original, representing enhanced performance.

Frequently Asked Questions (FAQ)

Q: Are Littelfuse 20102500001 and 20102500021 electrically identical to the Bel Fuse 5MT 250?

A: Both substitute parts match the critical electrical parameters: 250 mA current rating, 250 V AC voltage rating, and medium blow response time. They are electrically equivalent for standard circuit protection applications.

Q: Can I use these substitutes in applications requiring the full -55°C to 125°C operating temperature range?

A: The Littelfuse substitutes operate within -25°C to 70°C. Applications requiring operation outside this range are not suitable for these substitutes without additional thermal management evaluation.

Q: What is the difference between Littelfuse 20102500001 and 20102500021?

A: Both parts are electrically and mechanically identical. The difference lies in packaging: 20102500001 is supplied in bulk packaging, while 20102500021 is also supplied in bulk. Consult inventory availability and procurement requirements for selection.

Q: Are the substitute parts RoHS compliant?

A: Yes, both Littelfuse substitutes are ROHS3 compliant, whereas the original Bel Fuse 5MT 250 is non-compliant. This represents compliance improvement for systems subject to RoHS requirements.

Q: Do the substitute parts require the same holder as the original 5MT 250?

A: Yes. All parts maintain the 5mm x 20mm form factor and require a dedicated fuse holder for installation. Existing holder compatibility is maintained.

Q: What certifications do the substitute parts carry?

A: The Littelfuse substitutes carry cULus certification. The original part carried CE, CSA, and cULus certifications. Verify certification requirements for your specific application and regulatory jurisdiction.