Littelfuse 0451012.NRL Surface Mount Board Mount Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 0451012.NRL is a 12 A, 65 V AC/DC surface mount board mount fuse in the NANO²® 451 series. This fast-blow fuse is designed for circuit protection in applications requiring compact SMD packaging with 2-SMD square end block configuration. The part is active in production status and widely available in inventory. Equivalent and substitute parts are identified when identical electrical and mechanical parameters are maintained or when higher voltage ratings provide functional compatibility within the same package footprint and current rating specifications.

Substiute Parts

0451012.NRL

Littelfuse Inc.In Stock: 7370451012.NRL Datasheet

Current PartRFQ

0451012.MRL

Littelfuse Inc.In Stock: 1001370451012.MRL Datasheet

Parametric EquivalentRFQ

0453012.MR

Littelfuse Inc.In Stock: 62130453012.MR Datasheet

Parametric EquivalentRFQ

SF-2410F1200T-2

Bourns Inc.In Stock: 2717SF-2410F1200T-2 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 0451012.NRL are classified into two categories based on electrical and mechanical compatibility:

Parametric Equivalents (Identical Specifications): Parts that maintain all critical electrical parameters—current rating (12 A), voltage rating (65 V AC/DC), response time (fast blow), package configuration (2-SMD square end block), and physical dimensions (0.240" L x 0.106" W x 0.106" H)—are considered direct parametric equivalents. These parts differ only in manufacturer, series designation, or packaging format (tape & reel variant).

Direct Manufacturer Substitutes (Higher Voltage Rating): Parts with identical current rating (12 A), response time (fast blow), and package configuration but with elevated voltage ratings (86 V AC/DC) are classified as direct substitutes when the application circuit voltage does not exceed the substitute part's rating. These substitutes provide enhanced voltage margin and are compatible with the same PCB footprint and mounting process.

Parameter Comparison

Engineering Selection Recommendations

0451012.MRL (Littelfuse Inc., NANO²® 451 Series): This part is a parametric equivalent with identical electrical specifications and package configuration. It maintains the same 12 A current rating, 65 V AC/DC voltage rating, and fast-blow response time. The primary distinction is packaging format (tape & reel variant) and significantly higher inventory availability (100,100 units). Selection is appropriate when supply chain continuity or volume requirements favor this variant. Regulatory compliance (CSA, UL) and RoHS3 status are identical to the main part.

0453012.MR (Littelfuse Inc., NANO²® 453 Series): This part is a parametric equivalent with identical electrical and mechanical specifications to the 0451012.NRL. The series designation change (453 versus 451) reflects internal product line organization within Littelfuse but does not alter functional performance. All critical parameters—current rating, voltage rating, response time, package configuration, and physical dimensions—are maintained. This part is suitable for direct substitution and offers moderate inventory availability (6,105 units). Regulatory approvals and RoHS3 compliance are equivalent.

SF-2410F1200T-2 (Bourns Inc., SinglFuse™ SF-2410F-T Series): This part is a direct manufacturer substitute with elevated voltage rating (86 V AC/DC versus 65 V AC/DC) while maintaining the 12 A current rating, fast-blow response time, and 2-SMD square end block package. The higher voltage rating provides enhanced circuit protection margin and is compatible with applications operating at or below 65 V. Physical dimensions are nominally equivalent (0.240" L x 0.102" W x 0.102" H versus 0.240" L x 0.106" W x 0.106" H), with minor width and height variations that remain within typical PCB footprint tolerances. Breaking capacity is significantly higher (200 A versus 50 A), and DC cold resistance is lower (0.0045 Ohms versus 0.0049 Ohms). Regulatory approvals include cUL and UL certification. REACH status is affected for this part, requiring compliance verification in regulated markets. Selection is appropriate when higher voltage margin or superior breaking capacity is required.

Frequently Asked Questions (FAQ)

Q: Can 0451012.MRL be used as a direct replacement for 0451012.NRL?

A: Yes. The 0451012.MRL is a parametric equivalent with identical current rating (12 A), voltage rating (65 V AC/DC), response time (fast blow), package configuration (2-SMD square end block), and physical dimensions. The parts differ only in packaging format and manufacturer inventory designation. Direct substitution is appropriate without circuit redesign.

Q: What is the difference between 0451012.NRL and 0453012.MR?

A: Both parts are parametric equivalents with identical electrical specifications and package configuration. The series designation change (451 versus 453) reflects internal Littelfuse product line organization but does not affect functional performance. All critical parameters—current rating, voltage rating, response time, and physical dimensions—are maintained. Direct substitution is appropriate.

Q: Can SF-2410F1200T-2 replace 0451012.NRL in all applications?

A: SF-2410F1200T-2 is a direct manufacturer substitute suitable for applications where the circuit voltage does not exceed 65 V AC/DC. The substitute part has a higher voltage rating (86 V AC/DC), which provides enhanced protection margin. Physical dimensions are nominally equivalent with minor variations in width and height. Breaking capacity and DC cold resistance differ, but these parameters do not prevent substitution in standard circuit protection applications. Regulatory compliance (cUL, UL) is maintained. REACH status is affected; compliance verification is required for regulated markets.

Q: Are there any physical compatibility concerns when substituting SF-2410F1200T-2?

A: Physical dimensions are nominally equivalent. The main part measures 0.240" L x 0.106" W x 0.106" H, while SF-2410F1200T-2 measures 0.240" L x 0.102" W x 0.102" H. Width and height variations of 0.004" are within typical PCB footprint design tolerances for 2-SMD square end block packages. No redesign is required for standard applications.

Q: What is the significance of the higher breaking capacity in SF-2410F1200T-2?

A: SF-2410F1200T-2 has a breaking capacity of 200 A at rated voltage, compared to 50 A for the 0451012.NRL. Breaking capacity indicates the maximum fault current the fuse can safely interrupt without rupturing or creating a hazard. The higher breaking capacity in SF-2410F1200T-2 provides enhanced safety margin in high-fault-current applications but does not affect performance in standard circuit protection scenarios where fault currents remain below 50 A.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts—0451012.MRL, 0453012.MR, and SF-2410F1200T-2—are RoHS3 compliant. Moisture sensitivity level (MSL) is 1 (unlimited) for all parts, indicating no special moisture control requirements during storage or handling.

Q: What is the REACH status difference between the main part and SF-2410F1200T-2?

A: The main part (0451012.NRL) and Littelfuse substitutes (0451012.MRL, 0453012.MR) have REACH unaffected status. SF-2410F1200T-2 has REACH affected status, indicating that specific substance compliance verification is required for markets with REACH regulations. Compliance documentation should be obtained from the manufacturer for regulated applications.