MQ 15 Equivalent & Substitute Parts Reference

Part Overview

The MQ 15 is a 15A board mount axial fuse rated for 125V AC/DC operation, manufactured by Bel Fuse Inc. This component is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. The MQ 15 serves as a protection device in circuits requiring fast-blow response characteristics with through-hole mounting configuration.

Substiute Parts

MQ 15

Bel Fuse Inc.In Stock: 1140MQ 15 Datasheet

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0251015.MXL

Littelfuse Inc.In Stock: 32820251015.MXL Datasheet

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0251015.NRT1L

Littelfuse Inc.In Stock: 24020251015.NRT1L Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the MQ 15 are identified based on the following critical parameters that determine functional equivalence:

• Current Rating: 15 A (exact match required)
• Response Time: Fast Blow (characteristic must match)
• Mounting Type: Through Hole (physical installation requirement)
• Fuse Type: Board Mount Axial (form factor requirement)
• Breaking Capacity: 50A AC, 300A DC (protective capability)
• Operating Temperature Range: -55°C ~ 125°C (environmental compatibility)

The substitute parts 0251015.MXL and 0251015.NRT1L, both manufactured by Littelfuse Inc., meet these core electrical and mechanical parameters. These parts maintain identical current ratings, response characteristics, mounting configurations, and operating temperature ranges as the MQ 15. The primary difference lies in voltage rating (32V AC/DC versus 125V AC/DC), which represents a design constraint rather than a limitation for applications operating at or below 32V.

Parameter Comparison

Engineering Selection Recommendations

The 0251015.MXL and 0251015.NRT1L represent active production alternatives to the obsolete MQ 15. Both Littelfuse substitutes maintain CSA and cURus certifications, ensuring regulatory compliance for applications requiring these approvals. The 0251015.MXL is supplied in bulk packaging, while 0251015.NRT1L is available in cut tape format, accommodating different procurement and assembly workflows.

Selection between these two substitutes depends on packaging requirements and inventory management practices. The 0251015.NRT1L in cut tape format supports automated pick-and-place assembly operations, whereas bulk packaging of the 0251015.MXL suits manual assembly or kit-based distribution.

For applications operating at voltages exceeding 32V, neither substitute provides direct voltage equivalence to the MQ 15. In such cases, alternative fuse solutions rated for higher voltages must be evaluated independently.

Frequently Asked Questions (FAQ)

Q: Can the 0251015.MXL or 0251015.NRT1L be used as direct replacements for the MQ 15?

A: These parts are functionally equivalent for applications operating at or below 32V AC/DC. Both maintain identical current ratings (15A), response characteristics (fast blow), mounting configurations (through hole axial), and operating temperature ranges (-55°C to 125°C). The voltage rating difference represents the primary design constraint.

Q: What is the difference between 0251015.MXL and 0251015.NRT1L?

A: Both parts are electrically and mechanically identical. The difference is packaging: 0251015.MXL is supplied in bulk, while 0251015.NRT1L is supplied in cut tape format. Selection depends on assembly process requirements and inventory management practices.

Q: Are the substitute parts RoHS compliant?

A: The 0251015.MXL and 0251015.NRT1L are both ROHS3 compliant, whereas RoHS status is not specified for the MQ 15.

Q: What certifications do the substitute parts carry?

A: Both 0251015.MXL and 0251015.NRT1L carry CSA and cURus approvals. The MQ 15 additionally carries CE certification, which is not listed for the Littelfuse substitutes.

Q: Can these substitutes be used in applications rated for 125V?

A: No. The substitute parts are rated for 32V AC/DC maximum. Using them in 125V circuits exceeds their voltage rating and violates safe operating conditions. Alternative fuse solutions must be identified for higher-voltage applications.

Q: How do the melting I²t values compare?

A: The MQ 15 has a melting I²t of 70, while both Littelfuse substitutes have 68.8. This minor difference (approximately 1.7%) falls within acceptable tolerance for thermal protection characteristics.