MQ 10 Equivalent & Substitute Parts

Part Overview

The Bel Fuse Inc. MQ 10 is a 10A 125VAC/VDC board mount axial fuse with fast blow response time, designed for through-hole PCB applications. This part is classified as obsolete, making equivalent substitutes necessary for ongoing production and maintenance requirements. Littelfuse Inc. and SCHURTER Inc. offer direct functional equivalents that maintain electrical and mechanical compatibility within the specified parameter ranges.

Key Parameters

Parameter	Value
Current Rating	10 A
Voltage Rating (AC)	125 V
Voltage Rating (DC)	125 V
Response Time	Fast Blow
Mounting Type	Through Hole
Fuse Type	Board Mount (Cartridge Style Excluded)
Package / Case	Axial
Breaking Capacity @ Rated Voltage	50A AC, 300A DC
Operating Temperature Range	-55°C ~ 125°C

Substitute Part Grouping Explanation

Substitution eligibility is determined by matching the following critical parameters:

Current Rating: 10 A (exact match required)
Voltage Rating: 125 V AC and 125 V DC (exact match required)
Response Time: Fast Blow (exact match required)
Mounting Type: Through Hole (exact match required)
Fuse Type: Board Mount (Cartridge Style Excluded) (exact match required)
Breaking Capacity: Minimum 50A AC and 300A DC at rated voltage
Operating Temperature: Minimum -55°C to 125°C range
Approval Agencies: CSA, cURus certifications (baseline requirement)

All substitute parts listed meet these criteria. Dimensional variations within the axial package category and minor differences in melting I²t values remain within acceptable tolerance for board mount fuse applications.

Parameter Comparison

Parameter	MQ 10 (Bel Fuse)	0251010.MXL (Littelfuse)	0251010.NRT1L (Littelfuse)	7010.7150.13 (SCHURTER)
Manufacturer	Bel Fuse Inc.	Littelfuse Inc.	Littelfuse Inc.	SCHURTER Inc.
Current Rating (Amps)	10 A	10 A	10 A	10 A
Voltage Rating - AC	125 V	125 V	125 V	125 V
Voltage Rating - DC	125 V	125 V	125 V	125 V
Response Time	Fast Blow	Fast Blow	Fast Blow	Fast Blow
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole
Fuse Type	Board Mount (Cartridge Style Excluded)	Board Mount (Cartridge Style Excluded)	Board Mount (Cartridge Style Excluded)	Board Mount (Cartridge Style Excluded)
Package / Case	Axial	Axial	Axial	Cartridge, Non-Standard (Axial)
Breaking Capacity @ Rated Voltage	50A AC, 300A DC	50A AC, 300A DC	50A AC, 300A DC	300A
Melting I²t	25	25.5	25.5	39
Operating Temperature	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 85°C
DC Cold Resistance	0.006 Ohms	0.0072 Ohms	0.0072 Ohms	Not specified
Product Status	Obsolete	Active	Active	Active
Approval Agency	CE, CSA, cURus	CSA, cURus, TUV	CSA, cURus, TUV	CSA, UR

Engineering Selection Recommendations

Primary Substitutes (Littelfuse PICO® II 251 Series):

The 0251010.MXL and 0251010.NRT1L parts are direct functional equivalents with active product status. Both maintain identical electrical specifications (10A, 125VAC/VDC, fast blow) and operating temperature range (-55°C to 125°C). The 0251010.NRT1L offers superior inventory availability (338,860 pcs) compared to 0251010.MXL (3,652 pcs). Both carry CSA, cURus, and TUV certifications. The 0251010.NRT1L includes REACH compliance status, making it suitable for regulated markets. Dimensional differences (0.110" diameter vs. 0.125" diameter) are within acceptable tolerance for board mount applications.

Secondary Substitute (SCHURTER 7010.7150.13):

The SCHURTER 7010.7150.13 maintains electrical equivalence (10A, 125VAC/VDC, fast blow) with CSA and UR certifications. The operating temperature range is limited to -55°C to 85°C, which excludes high-temperature applications requiring the full -55°C to 125°C range. The melting I²t value (39) is higher than the original specification (25), indicating slower thermal response. This part is suitable for applications where the reduced temperature ceiling and altered thermal characteristics are acceptable.

Frequently Asked Questions (FAQ)

Q: Can the Littelfuse 0251010.MXL and 0251010.NRT1L be used interchangeably?

A: Yes. Both parts are from the same PICO® II 251 series and share identical electrical specifications, current rating, voltage rating, response time, and operating temperature range. The primary difference is packaging (Bulk vs. Cut Tape) and inventory availability. Selection depends on procurement requirements and supply chain considerations.

Q: What is the impact of the dimensional difference between the MQ 10 (0.125" diameter) and Littelfuse substitutes (0.110" diameter)?

A: The smaller diameter of Littelfuse parts (0.110") is compatible with through-hole PCB designs that accommodate the original 0.125" diameter. The reduced diameter provides improved mechanical fit in standard fuse holders and through-hole pads. No design modification is required.

Q: Is the SCHURTER 7010.7150.13 suitable for all applications?

A: The SCHURTER part is suitable for applications operating within -55°C to 85°C. Applications requiring operation at temperatures between 85°C and 125°C must use Littelfuse substitutes. Additionally, the higher melting I²t value (39 vs. 25) results in slower thermal response, which may affect circuit protection timing in sensitive applications.

Q: What certifications are required for my application?

A: All substitute parts carry CSA and cURus certifications, meeting baseline regulatory requirements. The Littelfuse parts include additional TUV certification. The SCHURTER part carries UR certification. Verify specific certification requirements for your target market and application before final selection.

Q: Does the DC cold resistance difference affect circuit performance?

A: The Littelfuse substitutes (0.0072 Ohms) have slightly higher DC cold resistance than the original MQ 10 (0.006 Ohms). This 0.0012 Ohm difference is negligible in most board mount fuse applications and does not affect circuit functionality or protection characteristics.

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