Electric Wire Resistance

Overview

Calculate the resistance of a copper or aluminum wire based on its dimensions and material.

Formula

$R = \rho \frac{L}{A}$

Calculator

Notes

• Results are approximate and should be verified for critical applications
• Input values should be within reasonable engineering ranges

Common Wire Materials

Materials frequently used for electrical wiring and their typical resistivity characteristics:

• Aluminum
• Constantan
• Copper
• Nichrome
• Platinum
• Silver
• Tungsten

Temperature Dependence of Resistance

The resistance of a conductor changes with temperature, described by the formula:

$R = R_0 \left[1 + \alpha (T - T_0)\right]$

where:

• $R$ is the resistance at temperature $T$,
• $R_0$ is the resistance at reference temperature $T_0$ (commonly 20°C),
• $\alpha$ is the temperature coefficient of resistance (in $\text{K}^{-1}$).

Key Definitions

• Resistivity ($\rho$): An intrinsic material property measuring opposition to electric current, with units $\Omega \cdot m$.
• Conductivity ($\sigma$): The reciprocal of resistivity, $\sigma = 1/\rho$, indicating electrical conductance, in $S/m$.
• Temperature Coefficient ($\alpha$): A factor expressing the relative change in resistance per degree of temperature.

References

• Original Source