MQ 3 Equivalent & Substitute Parts Reference

Part Overview

The MQ 3 is a board mount axial fuse manufactured by Bel Fuse Inc., rated for 3A at 125V AC/DC with fast blow response characteristics. This component is classified as obsolete, making equivalent substitutes necessary for ongoing production and maintenance applications. The MQ 3 serves as a protective device in circuits requiring reliable overcurrent protection with fast response times and compact axial packaging.

Substiute Parts

MQ 3

Bel Fuse Inc.In Stock: 887MQ 3 Datasheet

Current PartRFQ

0251003.MXL

Littelfuse Inc.In Stock: 94310251003.MXL Datasheet

DirectRFQ

0251003.NRT1L

Littelfuse Inc.In Stock: 1844280251003.NRT1L Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the MQ 3 is determined by strict equivalence across the following electrical and mechanical parameters:

• Current Rating: 3 A (exact match required)
• Voltage Rating: 125V AC and 125V DC (exact match required)
• Response Time: Fast Blow (exact match required)
• Mounting Type: Through Hole (exact match required)
• Fuse Type: Board Mount, Axial configuration (exact match required)
• Breaking Capacity: 50A AC, 300A DC (exact match required)
• Operating Temperature Range: -55°C ~ 125°C (exact match required)

The substitute parts identified—0251003.MXL and 0251003.NRT1L from Littelfuse Inc.—meet all electrical and mechanical requirements for direct substitution. Both are part of the PICO® II 251 series and maintain functional equivalence with the original MQ 3 component.

Parameter Comparison

Engineering Selection Recommendations

Both 0251003.MXL and 0251003.NRT1L are active production components from Littelfuse Inc. and provide direct electrical and mechanical equivalence to the obsolete MQ 3. Selection between these two substitutes is determined by packaging requirements:

• 0251003.MXL: Supplied in Bulk packaging. Use this variant when component procurement supports bulk inventory management.

• 0251003.NRT1L: Supplied in Cut Tape (CT) packaging. Use this variant for automated assembly processes or when tape-and-reel format is required for pick-and-place equipment.

Both substitutes carry expanded approval certifications (CCC, CSA, cURus, PSE, TUV) compared to the original MQ 3, providing broader regulatory compliance for international applications. The minor variations in DC Cold Resistance (0.0295 Ohms vs. 0.028 Ohms) and Melting I²t (1.19 vs. 1.1) remain within acceptable engineering tolerances for this fuse category and do not affect functional substitution.

Frequently Asked Questions (FAQ)

Q: Can 0251003.MXL and 0251003.NRT1L be used interchangeably with the MQ 3?

A: Yes. Both parts meet all electrical and mechanical requirements for direct substitution. The difference between them is packaging format only—Bulk versus Cut Tape—not electrical performance.

Q: What is the difference between Bulk and Cut Tape packaging?

A: Bulk packaging (0251003.MXL) is suitable for manual assembly and general inventory storage. Cut Tape packaging (0251003.NRT1L) is formatted for automated pick-and-place assembly equipment and tape-and-reel handling systems.

Q: Are there physical dimension differences between the MQ 3 and the substitute parts?

A: The substitute parts have a slightly smaller diameter (0.110" vs. 0.125") but maintain the same length (0.280"). Both fit standard through-hole axial fuse footprints designed for 3A 125V axial fuses.

Q: Do the substitute parts have better regulatory compliance than the original MQ 3?

A: Yes. The Littelfuse substitutes carry additional certifications (CCC, PSE, TUV) beyond the original approvals (CE, CSA, cURus), providing broader international regulatory coverage.

Q: What should I consider when selecting between the two substitute options?

A: Choose based on your assembly process. For manual assembly or general stock, use 0251003.MXL (Bulk). For automated assembly lines, use 0251003.NRT1L (Cut Tape).