Bel Fuse Inc. 5MT 500 Glass Cartridge Fuse Equivalent & Substitute Parts

Part Overview

The Bel Fuse Inc. 5MT 500 is a 500 mA, 250 V AC/DC glass cartridge fuse in a 5mm x 20mm package format that requires a holder for installation. This fuse is classified as obsolete, making identification of equivalent and substitute parts essential for ongoing system maintenance and component procurement. The 5MT series provides medium-blow response characteristics suitable for general circuit protection applications. Substitute parts must maintain electrical and mechanical compatibility while meeting current regulatory and compliance standards.

Substiute Parts

5MT 500

Bel Fuse Inc.In Stock: 10015MT 500 Datasheet

Current PartRFQ

20105000001

Littelfuse Inc.In Stock: 302220105000001 Datasheet

SimilarRFQ

20105000021

Littelfuse Inc.In Stock: 114520105000021 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 5MT 500 is determined by strict equivalence across the following electrical and mechanical parameters:

• Current Rating: 500 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. 20105000001 and 20105000021—meet all mandatory electrical and mechanical parameters. Both are active-status components from the Littelfuse 201 series, providing direct functional equivalence to the obsolete 5MT 500.

Parameter Comparison

Engineering Selection Recommendations

Both Littelfuse 20105000001 and 20105000021 provide direct electrical and mechanical substitution for the obsolete Bel Fuse 5MT 500. Selection between these two Littelfuse alternatives is based on availability and packaging preference, as both are functionally equivalent.

The Littelfuse substitutes offer the following advantages over the original part:

• Active product status ensures ongoing availability and supply chain continuity
• ROHS3 compliance aligns with current regulatory requirements
• Higher breaking capacity (80A vs. 35A) provides enhanced fault protection margin
• cULus certification maintains recognized safety approval

Consideration should be given to the reduced operating temperature range (-25°C ~ 70°C) of the Littelfuse parts compared to the original 5MT 500 (-55°C ~ 125°C). Applications requiring operation outside the -25°C ~ 70°C window require thermal performance validation.

Frequently Asked Questions (FAQ)

Q: Can Littelfuse 20105000001 or 20105000021 be used as direct replacements for the Bel Fuse 5MT 500?

A: Yes. Both Littelfuse parts match the mandatory electrical parameters (500 mA, 250 V AC, medium-blow response) and mechanical specifications (5mm x 20mm cartridge, requires holder). Both are functionally equivalent for standard circuit protection applications.

Q: What is the difference between Littelfuse 20105000001 and 20105000021?

A: Both parts are electrically and mechanically identical. The difference is packaging format: 20105000001 is supplied in bulk packaging, while 20105000021 is also supplied in bulk packaging. Selection depends on procurement and inventory requirements.

Q: Are there any thermal limitations when substituting with Littelfuse parts?

A: The Littelfuse substitutes operate within -25°C ~ 70°C, compared to the original 5MT 500 range of -55°C ~ 125°C. Applications requiring operation below -25°C or above 70°C must be evaluated for thermal compatibility before substitution.

Q: Do the Littelfuse substitutes maintain the same holder compatibility?

A: Yes. Both Littelfuse parts are 5mm x 20mm cartridge fuses requiring a holder, maintaining mechanical compatibility with existing 5MT 500 holder installations.

Q: What regulatory compliance changes occur with substitution?

A: The Littelfuse substitutes are ROHS3 compliant, whereas the original 5MT 500 is RoHS non-compliant. Both maintain cULus certification. Applications subject to RoHS requirements benefit from this compliance upgrade.