MQ 250TR Equivalent & Substitute Parts

Part Overview

The MQ 250TR is a 250 mA board mount axial fuse rated for 125 V AC/DC operation, manufactured by Bel Fuse Inc. This component is classified as obsolete, making equivalent substitutes necessary for ongoing production and maintenance applications. The fuse is designed for through-hole mounting with fast-blow response characteristics and is approved by CE, CSA, and cURus agencies.

Substiute Parts

MQ 250TR

Bel Fuse Inc.In Stock: 776MQ 250TR Datasheet

Current PartRFQ

0251.250NRT1L

Littelfuse Inc.In Stock: 1123350251.250NRT1L Datasheet

DirectRFQ

0251.250MRT1L

Littelfuse Inc.In Stock: 96580251.250MRT1L Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the MQ 250TR is determined by strict equivalence across the following electrical and mechanical parameters:

• Current Rating: 250 mA (exact match required)
• Voltage Rating: 125 V AC and 125 V DC (exact match required)
• Fuse Type: Board Mount, Through Hole, Axial configuration
• Response Time: Fast Blow characteristic
• Breaking Capacity: 50A AC, 300A DC minimum
• Operating Temperature: -55°C ~ 125°C range
• Approval Agencies: CSA and cURus certifications

The substitute parts identified—0251.250NRT1L and 0251.250MRT1L from Littelfuse Inc.—meet all electrical specifications. Physical dimensions show minor variation in diameter (0.110" vs. 0.125"), which remains within acceptable tolerance for through-hole board mount applications. Both substitutes are active products with current manufacturing status and inventory availability.

Parameter Comparison

Engineering Selection Recommendations

Both 0251.250NRT1L and 0251.250MRT1L are qualified substitutes for the obsolete MQ 250TR based on electrical equivalence and regulatory compliance. The Littelfuse PICO® II 251 series parts maintain CSA and cURus certifications required for safety-critical applications.

Selection between the two Littelfuse options depends on supply chain requirements: 0251.250NRT1L offers higher inventory availability (112,295 pcs) with Cut Tape packaging, while 0251.250MRT1L provides lower stock levels (9,579 pcs) with REACH Unaffected status. Both parts are ROHS3 compliant and suitable for direct replacement in existing designs.

The minor dimensional difference in lead diameter (0.110" vs. 0.125") does not affect electrical performance or through-hole mounting compatibility, as both diameters are standard for axial fuse leads.

Frequently Asked Questions (FAQ)

Q: Can 0251.250NRT1L and 0251.250MRT1L be used interchangeably with MQ 250TR?

A: Yes. Both parts meet all electrical specifications: 250 mA current rating, 125 V AC/DC voltage rating, fast-blow response, and identical breaking capacity. Both are CSA and cURus certified for equivalent safety performance.

Q: What is the significance of the diameter difference (0.125" vs. 0.110")?

A: The diameter variation reflects manufacturing tolerances between manufacturers. Both dimensions are within standard specifications for axial fuse leads and are compatible with through-hole PCB mounting patterns designed for 250 mA fuses.

Q: Why does MQ 250TR have CE approval while the Littelfuse substitutes do not list it?

A: CE marking requirements vary by product classification and market region. CSA and cURus certifications provide equivalent safety validation for North American applications. Verify regional compliance requirements for your specific application.

Q: What is the difference between 0251.250NRT1L and 0251.250MRT1L?

A: Both parts are electrically and mechanically identical. The primary difference is REACH compliance status: 0251.250NRT1L is REACH Affected, while 0251.250MRT1L is REACH Unaffected. Select based on your supply chain and regulatory requirements.

Q: Is the higher DC Cold Resistance (0.665 Ohms vs. 0.52 Ohms) a concern?

A: No. The resistance difference is within acceptable tolerance for fuse applications and does not affect circuit performance at the specified 250 mA rating.

Q: What packaging options are available for the substitute parts?

A: 0251.250NRT1L is supplied in Cut Tape (CT) packaging. 0251.250MRT1L packaging is also Cut Tape (CT). Confirm packaging requirements with your procurement process.