Littelfuse 0251012.NRT1 Equivalent & Substitute Parts

Part Overview

The Littelfuse 0251012.NRT1 is a 12 A, 32 V AC/DC board mount axial fuse from the PICO® II 251 series. This component is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. The part features fast-blow response characteristics, CSA and cURus approvals, and operates across a temperature range of -55°C to 125°C. Substitute parts maintain identical electrical and mechanical specifications while offering active product status and improved compliance certifications.

Key Parameters

Parameter	Value
Current Rating	12 A
Voltage Rating (AC)	32 V
Voltage Rating (DC)	32 V
Response Time	Fast Blow
Mounting Type	Through Hole
Package / Case	Axial
Breaking Capacity @ Rated Voltage	50A AC, 300A DC
Melting I²t	45.2
DC Cold Resistance	0.0059 Ohms
Operating Temperature Range	-55°C ~ 125°C
Size / Dimension	0.110" Dia x 0.280" L (2.80mm x 7.11mm)
Approval Agencies	CSA, cURus

Substitute Part Grouping Explanation

Substitution for the 0251012.NRT1 is determined by strict equivalence across the following critical parameters:

Current Rating: 12 A
Voltage Rating: 32 V AC and 32 V DC
Response Time: Fast Blow
Mounting Type: Through Hole
Package / Case: Axial
Breaking Capacity @ Rated Voltage: 50A AC, 300A DC (Littelfuse parts) or 300A (SCHURTER part)
Melting I²t: 45.2 (Littelfuse parts) or 57 (SCHURTER part)
DC Cold Resistance: 0.0059 Ohms (Littelfuse parts)
Operating Temperature Range: -55°C ~ 125°C (Littelfuse parts) or -55°C ~ 85°C (SCHURTER part)
Size / Dimension: 0.110" Dia x 0.280" L (Littelfuse parts) or 0.093" Dia x 0.315" L (SCHURTER part)

Littelfuse parts 0251012.HAT1L, 0251012.MRT1L, 0251012.NAT1L, and 0251012.NRT1L are parametric equivalents with identical electrical characteristics and mechanical dimensions. The SCHURTER 7010.7160.13 is a direct manufacturer alternative with minor dimensional and thermal operating range variations.

Parameter Comparison

Parameter	0251012.NRT1	0251012.HAT1L	0251012.MRT1L	0251012.NAT1L	0251012.NRT1L	7010.7160.13
Manufacturer	Littelfuse Inc.	Littelfuse Inc.	Littelfuse Inc.	Littelfuse Inc.	Littelfuse Inc.	SCHURTER Inc.
Current Rating (Amps)	12 A	12 A	12 A	12 A	12 A	12 A
Voltage Rating - AC	32 V	32 V	32 V	32 V	32 V	32 V
Voltage Rating - DC	32 V	32 V	32 V	32 V	32 V	32 V
Response Time	Fast Blow	Fast Blow	Fast Blow	Fast Blow	Fast Blow	Fast Blow
Mounting Type	Through Hole	Through Hole	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)	Board Mount (Cartridge Style Excluded)	Board Mount (Cartridge Style Excluded)
Package / Case	Axial	Axial	Axial	Axial	Axial	Cartridge, Non-Standard (Axial)
Breaking Capacity @ Rated Voltage	50A AC, 300A DC	50A AC, 300A DC	50A AC, 300A DC	50A AC, 300A DC	50A AC, 300A DC	300A
Melting I²t	45.2	45.2	45.2	45.2	45.2	57
DC Cold Resistance	0.0059 Ohms	0.0059 Ohms	0.0059 Ohms	0.0059 Ohms	0.0059 Ohms	Not specified
Operating Temperature	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 85°C
Size / Dimension	0.110" Dia x 0.280" L (2.80mm x 7.11mm)	0.110" Dia x 0.280" L (2.80mm x 7.11mm)	0.110" Dia x 0.280" L (2.80mm x 7.11mm)	0.110" Dia x 0.280" L (2.80mm x 7.11mm)	0.110" Dia x 0.280" L (2.80mm x 7.11mm)	0.093" Dia x 0.315" L (2.36mm x 8.00mm)
Product Status	Obsolete	Active	Active	Active	Active	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Approval Agency	CSA, cURus	CSA, cURus	CSA, cURus	CSA, cURus	CSA, cURus	CSA, UR
Packaging	Not specified	Cut Tape (CT)	Cut Tape (CT)	Cut Tape (CT)	Cut Tape (CT)	Bulk
Inventory Status	1104 Pcs New Original In Stock	1020 Pcs New Original In Stock	1225 Pcs New Original In Stock	10336 Pcs New Original In Stock	22500 Pcs New Original In Stock	1589 Pcs New Original In Stock

Engineering Selection Recommendations

For applications requiring direct replacement of the obsolete 0251012.NRT1, the Littelfuse parametric equivalents 0251012.HAT1L, 0251012.MRT1L, 0251012.NAT1L, and 0251012.NRT1L are preferred selections. These parts maintain identical electrical specifications, mechanical dimensions, and thermal operating ranges while offering active product status and ROHS3 compliance. All four Littelfuse alternatives carry CSA and cURus approvals consistent with the original part.

The SCHURTER 7010.7160.13 serves as an alternative direct manufacturer substitute with equivalent electrical performance. This part differs in physical dimensions (0.093" Dia x 0.315" L versus 0.110" Dia x 0.280" L), maximum operating temperature (85°C versus 125°C upper limit), and melting I²t value (57 versus 45.2). PCB layout and thermal design considerations must account for these dimensional and thermal differences.

Selection among Littelfuse alternatives may be based on packaging requirements (Cut Tape) and inventory availability. The 0251012.NRT1L variant offers the highest inventory level at 22,500 pieces.

Frequently Asked Questions (FAQ)

Q: Can the 0251012.NRT1 be directly replaced with any of the Littelfuse substitute parts?

A: Yes. The Littelfuse parts 0251012.HAT1L, 0251012.MRT1L, 0251012.NAT1L, and 0251012.NRT1L are parametric equivalents with identical current ratings (12 A), voltage ratings (32 V AC/DC), response characteristics (Fast Blow), and physical dimensions (0.110" Dia x 0.280" L). All maintain the same operating temperature range (-55°C ~ 125°C) and DC cold resistance (0.0059 Ohms).

Q: What are the key differences between Littelfuse and SCHURTER alternatives?

A: The SCHURTER 7010.7160.13 differs in three areas: physical dimensions (0.093" Dia x 0.315" L), maximum operating temperature (85°C upper limit versus 125°C), and melting I²t (57 versus 45.2). Electrical ratings and response characteristics remain equivalent. PCB layout compatibility and thermal environment must be evaluated before selection.

Q: Why is the original 0251012.NRT1 marked as obsolete?

A: The original part is obsolete, necessitating substitution with active alternatives. The Littelfuse parametric equivalents provide direct functional replacement with improved compliance certifications (ROHS3 Compliant versus RoHS non-compliant).

Q: Are all substitute parts RoHS compliant?

A: Yes. All substitute parts listed—0251012.HAT1L, 0251012.MRT1L, 0251012.NAT1L, 0251012.NRT1L, and 7010.7160.13—are ROHS3 compliant. The original 0251012.NRT1 is RoHS non-compliant.

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

A: Littelfuse alternatives are supplied in Cut Tape (CT) packaging. The SCHURTER part is supplied in Bulk packaging. Packaging selection depends on production volume and assembly process requirements.

Q: Do all substitute parts carry the same regulatory approvals?

A: Littelfuse substitutes carry CSA and cURus approvals matching the original part. The SCHURTER alternative carries CSA and UR approvals, providing equivalent regulatory coverage for most applications.

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