1. What is the Fusing Current Equation?

The fusing current equation calculates the current at which a wire will melt or "fuse" based on its diameter and material properties. The formula relates fusing current to wire diameter through a material-specific constant.

2. How Does the Calculator Work?

The calculator uses the fusing current equation:

Where:

• \( I \) — Fusing current (Amperes)
• \( k \) — Material constant (A/mm^(3/2))
• \( d \) — Wire diameter (mm)

Explanation: The equation shows that fusing current increases with the 3/2 power of the wire diameter, with different materials having different proportionality constants.

3. Importance of Fusing Current Calculation

Details: Calculating fusing current is essential for electrical safety, fuse design, and determining appropriate wire gauges for specific current-carrying applications.

4. Using the Calculator

Tips: Enter the material constant (k) in A/mm^(3/2) and wire diameter in mm. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What are typical values for the constant k?
A: The constant varies by material. Copper typically has k ≈ 80 A/mm^(3/2), while aluminum has k ≈ 59 A/mm^(3/2).

Q2: Why is the exponent 3/2 used in the equation?
A: The 3/2 exponent comes from the relationship between current carrying capacity, heat generation, and surface area for heat dissipation.

Q3: Does insulation affect fusing current?
A: Yes, insulation can significantly affect fusing current by trapping heat. The basic equation assumes bare wire in free air.

Q4: Is this equation applicable to all wire types?
A: The equation works well for common conductive materials but may need adjustment for special alloys or extreme conditions.

Q5: How accurate is this calculation for fuse design?
A: While useful for estimation, actual fuse design requires consideration of additional factors like ambient temperature, duration of overload, and specific safety margins.