MQ 7 Equivalent & Substitute Parts

Part Overview

The MQ 7 is a 7A 125VAC/VDC board mount axial fuse manufactured by Bel Fuse Inc. This component is classified as obsolete, making equivalent substitute parts necessary for ongoing circuit protection applications. The MQ 7 series provides fast-blow protection in through-hole axial configurations suitable for legacy and current production designs requiring identical electrical and mechanical performance.

Substiute Parts

MQ 7

Bel Fuse Inc.In Stock: 788MQ 7 Datasheet

Current PartRFQ

0251007.MXL

Littelfuse Inc.In Stock: 24460251007.MXL Datasheet

DirectRFQ

0251007.NRT1L

Littelfuse Inc.In Stock: 1751210251007.NRT1L Datasheet

DirectRFQ

7010.7140.13

SCHURTER Inc.In Stock: 7157010.7140.13 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the MQ 7 is determined by strict equivalence across the following parameters: current rating (7A), AC voltage rating (125V), DC voltage rating (125V), response time (fast blow), mounting type (through hole), and fuse type (board mount axial). The substitute parts listed maintain these core electrical specifications while offering active product status and improved availability.

Two primary substitute groups are identified:

Group 1: Littelfuse PICO® II 251 Series – Parts 0251007.MXL and 0251007.NRT1L maintain identical electrical ratings and fast-blow characteristics. These parts differ in packaging (bulk versus cut tape) and have slightly reduced physical dimensions (0.110" diameter versus 0.125") with marginally lower DC cold resistance (0.0107 Ohms versus 0.012 Ohms). Melting I²t is 10.4 versus 8 for the original part.

Group 2: SCHURTER 172322 Series – Part 7010.7140.13 maintains identical electrical ratings and fast-blow response. Physical dimensions differ (0.093" diameter x 0.315" length), and melting I²t is 13. Operating temperature maximum is reduced to 85°C. Breaking capacity at rated voltage is 300A (AC specification not provided).

Parameter Comparison

Engineering Selection Recommendations

Littelfuse 0251007.MXL and 0251007.NRT1L are the primary substitutes for the MQ 7. Both parts maintain full electrical equivalence with identical current, voltage, and breaking capacity ratings. The Littelfuse parts are active products with superior availability (2361 and 175060 units in stock respectively versus 711 for the original). Both carry CSA, cURus, and TUV certifications, with RoHS3 compliance. The difference between these two Littelfuse options is packaging: 0251007.MXL is supplied in bulk, while 0251007.NRT1L is supplied in cut tape format. Physical dimensions are slightly reduced, which may require PCB layout verification for tight spacing applications.

SCHURTER 7010.7140.13 is a secondary substitute option. While it maintains electrical equivalence in current, voltage, and response time, it differs in physical dimensions and has a reduced maximum operating temperature (85°C versus 125°C). This part is suitable only for applications where the lower temperature rating does not conflict with circuit requirements. SCHURTER certification includes CSA and UR.

For new designs and production continuity, Littelfuse 0251007.NRT1L is recommended due to highest inventory availability and active product status.

Frequently Asked Questions (FAQ)

Q: Can the Littelfuse 0251007.MXL or 0251007.NRT1L be used as direct replacements for the MQ 7?

A: Yes. Both Littelfuse parts maintain identical electrical specifications: 7A current rating, 125V AC/DC voltage rating, fast-blow response, 50A AC and 300A DC breaking capacity, and through-hole axial mounting. Physical dimensions are slightly smaller (0.110" diameter versus 0.125"), requiring verification that PCB pad spacing accommodates the reduced lead diameter.

Q: What is the difference between Littelfuse 0251007.MXL and 0251007.NRT1L?

A: Both parts are electrically and mechanically identical. The difference is packaging: 0251007.MXL is supplied in bulk, while 0251007.NRT1L is supplied in cut tape format. Selection depends on assembly process requirements and inventory management preferences.

Q: Can the SCHURTER 7010.7140.13 replace the MQ 7 in all applications?

A: The SCHURTER part maintains electrical equivalence but has a reduced maximum operating temperature of 85°C compared to the MQ 7's 125°C. It is suitable only for applications where ambient and operating temperatures remain below 85°C. Physical dimensions also differ, requiring PCB layout verification.

Q: Are there compliance or certification differences between the substitutes?

A: The MQ 7 carries CE, CSA, and cURus certifications. Littelfuse parts add TUV certification and include RoHS3 compliance. SCHURTER carries CSA and UR certifications. All parts are REACH unaffected and classified as EAR99 for export control purposes.

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

A: Melting I²t indicates the thermal energy required to melt the fuse element. The MQ 7 has I²t of 8, while Littelfuse parts have 10.4 and SCHURTER has 13. Higher I²t values indicate slightly slower thermal response. For fast-blow protection circuits, verify that the substitute's I²t remains acceptable for the specific application's inrush current and fault detection timing.

Q: Which substitute offers the best availability?

A: Littelfuse 0251007.NRT1L has the highest inventory availability at 175,060 units in stock, followed by 0251007.MXL at 2,361 units. The original MQ 7 has 711 units available but is obsolete.