TR-5 382 Series 3.15A 250V Time-Lag Miniature Fuse

TR-5 382 Series 3.15A 250V Time-Lag Miniature Fuse is an indispensable safety component, consequently protecting sensitive electronic circuits from damaging overcurrent conditions. This specific model, the 3.15A, belongs to the popular cylindrical miniature TR-5 series, which manufacturers widely recognize for its compact design and time-lag (slow-blow) characteristic. The time-lag feature allows brief, harmless current surges—like those experienced during equipment startup—to pass without interrupting the circuit, however, it quickly interrupts sustained overcurrents or short circuits. Rated for 250V AC, this fuse provides reliable primary circuit protection in power supplies, lighting, and consumer electronics. Therefore, designers specify this fuse when they require high breaking capacity combined with space-saving installation.

Key Features:

• Time-Lag (Slow-Blow) Characteristic: This feature handles transient inrush currents without opening, greatly enhancing the reliability of equipment that contains motors or transformers.
• High Breaking Capacity: The fuse safely interrupts high fault currents, offering robust protection for both the device and the power source.
• Compact TR-5 Form Factor: The cylindrical radial-leaded package (5 x 8.5 mm) saves valuable space on the Printed Circuit Board (PCB).
• RoHS Compliant and Halogen Free: The construction adheres to environmental standards, making it suitable for global market applications.
• International Safety Approvals: Carriers global certifications like UL, VDE, and CCC, ensuring adherence to strict safety standards worldwide.

Technical Specifications:

• Current Rating (I_N): 3.15 Amperes (A)
• Voltage Rating (V_R): 250 V_AC (Nominal)
• Fuse Characteristic: Time-Lag (T) / Slow Blow
• Breaking Capacity (I_R): 35 A (at 250 V_AC)
• Nominal Cold Resistance: ≈ 0.057 Ω
• Operating Temperature Range: −55°C to +125°C

Mechanical Specifications:

• Package Type: Radial Leaded Cylindrical Miniature Fuse
• Construction: Ceramic Body with Silver-plated End Caps
• Lead Material: Tinned Copper Wire (Axial or Radial)
• Mounting: Through-Hole Technology (THT)

Dimensions:

• Body Diameter: ≈ 5.0 mm
• Body Length: ≈ 8.5 mm
• Lead Spacing (Pitch): 5.0 mm (Standard for TR-5 series)
• Lead Diameter: ≈ 0.6 mm

Pinout and Wiring:

• Pin 1 & Pin 2 (Circuit Connection): This is a non-polarized two-terminal device; it connects in series with the load in the circuit line path (either live or neutral).
• Wiring Note: Always install the fuse on the primary side of the power supply or circuit, physically locating it as close to the power input as possible to protect the maximum amount of circuitry. Furthermore, designers often use a specialized fuse holder on the PCB to facilitate easy replacement.

Datasheet Reference:

• Download Littelfuse TR-5 382 Series Datasheet

Commonly Used in:

• AC/DC Power Supplies: Provides primary overcurrent protection for the input stage of switching power supplies.
• LED Lighting Fixtures: Essential for protecting the ballast/driver circuitry from power surges and shorts.
• Consumer Appliances: Used in televisions, refrigerators, printers, and other home electronics that experience start-up surges.

Applications:

• Protection for Transformers: The time-lag feature prevents the fuse from blowing during the high magnetic inrush current experienced by power transformers at turn-on.
• Circuit Board Primary Protection: Serves as the first line of defense against catastrophic failure due to short circuits or prolonged overload conditions.
• Medical and Industrial Equipment: Ensures safety shut-down in equipment where reliable, delayed tripping is required.

Equivalent Models:

• Wickmann / Littelfuse 392 Series: This radial fuse offers similar ratings and physical characteristics, representing a common cross-reference.
• Bussmann TR5-3.15-R: A functionally identical time-lag radial lead fuse rated at 3.15A. In addition, several manufacturers produce compatible versions, often prefixed with ‘T’.

Package Includes:

• 1 x TR-5 382 Series 3.15A 250V Time-Lag Miniature Fuse