5MT 375-R Equivalent & Substitute Parts

Part Overview

The 5MT 375-R is a 375 mA, 250 V AC/DC glass cartridge fuse manufactured by Bel Fuse Inc. with a 5mm x 20mm form factor. This component is classified as obsolete, necessitating identification of equivalent substitute parts for ongoing system maintenance and new designs. The fuse features medium blow response characteristics and is designed for applications requiring holder-based mounting in compact electrical protection circuits.

Substiute Parts

5MT 375-R

Bel Fuse Inc.In Stock: 12325MT 375-R Datasheet

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5ST 315-R

Bel Fuse Inc.In Stock: 176095ST 315-R Datasheet

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0217.400MXP

Littelfuse Inc.In Stock: 16670217.400MXP Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 5MT 375-R are identified based on the following critical parameters that must align for functional equivalence:

• Form Factor: 5mm x 20mm cartridge glass fuse (physical compatibility with existing holders)
• Voltage Rating: 250 V AC minimum
• Mounting Configuration: Requires holder-based installation
• Fuse Type: Glass cartridge construction
• Operating Temperature Range: -55°C ~ 125°C capability
• Regulatory Compliance: CE, CSA, or equivalent certifications

The substitute parts listed below meet these core requirements. Variations in current rating, response time characteristics, and breaking capacity are noted as they affect circuit protection behavior and must be evaluated against specific application requirements.

Parameter Comparison

Engineering Selection Recommendations

5ST 315-R (Bel Fuse Inc.)

This substitute is manufactured by the same original equipment manufacturer as the 5MT 375-R. It maintains identical physical dimensions, voltage rating, and operating temperature range. The 5ST 315-R is currently in active production status with significantly higher inventory availability (17,528 pcs). The primary distinction is the reduced current rating (315 mA versus 375 mA) and slow blow response characteristic. This part carries expanded regulatory certifications including CCC, PSE, and IMQ, providing broader geographic compliance coverage. Selection of this substitute requires confirmation that the lower current rating is compatible with circuit protection requirements.

0217.400MXP (Littelfuse Inc.)

This substitute provides a current rating of 400 mA, positioned above the original 375 mA specification. It maintains the 250 V AC voltage rating, 5mm x 20mm form factor, and identical breaking capacity. The 0217.400MXP features fast blow response characteristics, contrasting with the medium blow response of the 5MT 375-R. This part is actively produced with moderate inventory levels (1,558 pcs) and carries comprehensive regulatory approvals including UL and K-MARK certifications. The fast blow response and higher current rating necessitate application-specific validation to ensure circuit protection behavior remains appropriate.

Both substitute parts are ROHS3 compliant and maintain the required operating temperature range. Selection between these options depends on whether the application can accommodate variations in current rating and response time characteristics.

Frequently Asked Questions (FAQ)

Q: Can the 5ST 315-R be used as a direct replacement for the 5MT 375-R?

A: The 5ST 315-R shares the same physical form factor (5mm x 20mm), voltage rating (250 V AC), and mounting configuration. However, the current rating is reduced from 375 mA to 315 mA, and the response time changes from medium blow to slow blow. Direct substitution is possible only if the circuit protection requirements accommodate these parameter changes.

Q: What is the primary difference between the 5MT 375-R and 0217.400MXP?

A: Both parts maintain 250 V AC rating and 5mm x 20mm dimensions. The 0217.400MXP has a higher current rating (400 mA versus 375 mA) and fast blow response instead of medium blow. The manufacturers differ (Littelfuse versus Bel Fuse), resulting in different regulatory certifications and DC cold resistance values.

Q: Are all substitute parts physically compatible with existing 5mm x 20mm fuse holders?

A: Yes. All listed substitute parts conform to the 5mm x 20mm cartridge glass fuse standard and are compatible with holders designed for this form factor. Physical dimensions are standardized across all three parts.

Q: Which substitute has the best regulatory coverage?

A: The 0217.400MXP carries the broadest set of regulatory approvals, including UL, CCC, CE, CSA, K-MARK, SEMKO, and VDE. The 5ST 315-R includes CCC, CE, CSA, cURus, IMQ, PSE, SEMKO, and VDE certifications. Selection depends on the specific geographic and industry compliance requirements of the application.

Q: What does "response time" mean in fuse specifications?

A: Response time indicates how quickly the fuse element melts under overcurrent conditions. Fast blow fuses respond rapidly to current surges, medium blow fuses provide intermediate response, and slow blow fuses tolerate temporary overcurrent before melting. The choice affects circuit protection behavior and must align with application requirements.

Q: Can I use a higher current rating fuse as a substitute?

A: No. Using a fuse with a higher current rating than specified provides inadequate circuit protection and increases risk of equipment damage or safety hazards. The 0217.400MXP (400 mA) should only be selected if the application specifically requires this higher rating.

Q: What is the significance of the melting I²t value?

A: The melting I²t value indicates the thermal energy required to melt the fuse element. Lower values indicate faster response to overcurrent. The 0217.400MXP has a significantly lower melting I²t (0.125) compared to the 5MT 375-R (0.47), resulting in faster fault detection and circuit interruption.