Littelfuse 0251010.NRT2 Equivalent & Substitute Parts

Part Overview

The Littelfuse 0251010.NRT2 is a 10 A, 125 V AC/DC board mount axial fuse from the PICO® II 251 series. This part is classified as obsolete, which necessitates identification of active equivalent alternatives for ongoing design support and procurement. The part features fast-blow response characteristics, CSA/cURus/TUV approvals, and is rated for -55°C to 125°C operation. Substitute parts maintain identical electrical and mechanical specifications while offering active product status and improved compliance profiles.

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
Package / Case	Axial
Breaking Capacity (AC)	50 A
Breaking Capacity (DC)	300 A
Melting I²t	25.5
DC Cold Resistance	0.0072 Ohms
Size / Dimension	0.110" Dia x 0.280" L (2.80mm x 7.11mm)
Operating Temperature Range	-55°C ~ 125°C
Approval Agencies	CSA, cURus, TUV
Series	PICO® II 251

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict equivalence across the following parameters: current rating (10 A), AC voltage rating (125 V), DC voltage rating (125 V), response time (Fast Blow), mounting type (Through Hole), package type (Axial), breaking capacity (50 A AC / 300 A DC), melting I²t (25.5), DC cold resistance (0.0072 Ohms), physical dimensions (0.110" Dia x 0.280" L), and approval agencies (CSA, cURus, TUV).

All Littelfuse PICO® II 251 series substitutes listed maintain these electrical and mechanical parameters identically. Differences exist only in packaging format (Tape & Reel, Cut Tape, Tape & Box, or Bulk) and product status (Active vs. Obsolete). The cross-manufacturer substitute (SCHURTER 7010.7150.13) maintains electrical equivalence but differs in physical dimensions (0.093" Dia x 0.315" L), melting I²t (39), and operating temperature range (-55°C ~ 85°C), requiring design verification before implementation.

Parameter Comparison

Part Number	Manufacturer	Current (A)	Voltage AC (V)	Voltage DC (V)	Response	Breaking Capacity AC (A)	Breaking Capacity DC (A)	Melting I²t	DC Resistance (Ω)	Dimension (in)	Status	Packaging	RoHS
0251010.NRT2	Littelfuse	10	125	125	Fast Blow	50	300	25.5	0.0072	0.110 x 0.280	Obsolete	Tape & Reel	Non-compliant
0251010.MXL	Littelfuse	10	125	125	Fast Blow	50	300	25.5	0.0072	0.110 x 0.280	Active	Bulk	ROHS3
0251010.HAT1L	Littelfuse	10	125	125	Fast Blow	50	300	25.5	0.0072	0.110 x 0.280	Active	Cut Tape	ROHS3
0251010.MAT1JL	Littelfuse	10	125	125	Fast Blow	50	300	25.5	0.0072	0.110 x 0.280	Active	Cut Tape	ROHS3
0251010.MAT1L	Littelfuse	10	125	125	Fast Blow	50	300	25.5	0.0072	0.110 x 0.280	Active	Cut Tape	ROHS3
0251010.MRT1JL	Littelfuse	10	125	125	Fast Blow	50	300	25.5	0.0072	0.110 x 0.280	Active	Tape & Reel	ROHS3
0251010.MRT1L	Littelfuse	10	125	125	Fast Blow	50	300	25.5	0.0072	0.110 x 0.280	Active	Cut Tape	ROHS3
0251010.NAT1L	Littelfuse	10	125	125	Fast Blow	50	300	25.5	0.0072	0.110 x 0.280	Active	Tape & Box	ROHS3
0251010.NRT1JL	Littelfuse	10	125	125	Fast Blow	50	300	25.5	0.0072	0.110 x 0.280	Active	Tape & Reel	ROHS3
0251010.NRT1L	Littelfuse	10	125	125	Fast Blow	50	300	25.5	0.0072	0.110 x 0.280	Active	Cut Tape	ROHS3
7010.7150.13	SCHURTER	10	125	125	Fast Blow	—	300	39	—	0.093 x 0.315	Active	Bulk	ROHS3

Engineering Selection Recommendations

For direct replacement of the obsolete 0251010.NRT2, select from active Littelfuse PICO® II 251 series alternatives that maintain identical electrical and mechanical specifications. The recommended manufacturer substitute is 0251010.MXL (Bulk packaging, ROHS3 compliant, 3652 pcs in stock). For automated assembly processes requiring tape formats, 0251010.NRT1L (Cut Tape, highest inventory at 338,860 pcs) or 0251010.MRT1JL (Tape & Reel) are suitable. All Littelfuse alternatives carry CSA, cURus, and TUV approvals matching the original part.

The SCHURTER 7010.7150.13 is electrically equivalent but exhibits dimensional and thermal differences (0.093" Dia x 0.315" L vs. 0.110" Dia x 0.280" L; -55°C ~ 85°C vs. -55°C ~ 125°C; melting I²t 39 vs. 25.5). This part is suitable only where board layout accommodates the larger cartridge form factor and operating temperature does not exceed 85°C.

Frequently Asked Questions (FAQ)

Q: Can 0251010.NRT1L be used as a direct replacement for 0251010.NRT2?

A: Yes. Both parts are identical in electrical ratings (10 A, 125 V AC/DC), response time (Fast Blow), breaking capacity (50 A AC / 300 A DC), melting I²t (25.5), physical dimensions (0.110" Dia x 0.280" L), and approvals (CSA, cURus, TUV). The difference is packaging format (Cut Tape vs. Tape & Reel) and product status (Active vs. Obsolete). 0251010.NRT1L is the preferred choice due to active status and extensive inventory availability.

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

A: Cut Tape (CT) packaging provides individual component strips cut to specified lengths, suitable for manual assembly or small-batch production. Tape & Reel (TR) packaging supplies components on continuous reels, optimized for high-speed automated pick-and-place assembly. Both formats contain identical components; selection depends on assembly process requirements.

Q: Is the SCHURTER 7010.7150.13 a suitable substitute?

A: The SCHURTER part maintains electrical equivalence (10 A, 125 V AC/DC, Fast Blow, 300 A DC breaking capacity) but differs in three critical parameters: physical dimensions (0.093" Dia x 0.315" L vs. 0.110" Dia x 0.280" L), melting I²t (39 vs. 25.5), and maximum operating temperature (85°C vs. 125°C). Use only if board layout accommodates the larger cartridge form and thermal environment does not exceed 85°C.

Q: What does RoHS3 compliance mean for this fuse?

A: ROHS3 compliance indicates the part meets Restriction of Hazardous Substances Directive requirements, restricting lead, cadmium, mercury, hexavalent chromium, and specified brominated flame retardants. The original 0251010.NRT2 is RoHS non-compliant; all active substitutes are ROHS3 compliant, providing environmental and regulatory advantages for new designs.

Q: Are all Littelfuse PICO® II 251 series 10 A fuses interchangeable?

A: All listed Littelfuse PICO® II 251 series 10 A fuses maintain identical electrical and mechanical specifications. Differences exist only in packaging format and product status. Selection should be based on assembly process requirements (manual vs. automated) and inventory availability rather than electrical performance.

Q: What is the significance of melting I²t value?

A: Melting I²t (25.5 for Littelfuse parts, 39 for SCHURTER) defines the thermal energy required to melt the fuse element. Lower values indicate faster response to overcurrent conditions. The Littelfuse value of 25.5 is standard for this 10 A fast-blow rating; the SCHURTER value of 39 represents a different thermal characteristic and should not be assumed equivalent without circuit analysis.

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