How to Calculate Ampacity

By Society & Culture & Entertainment Last updated Monday, June/03/2024

1). Get the value of the temperature of the conductor (called TC) and the ambient temperature of the air or soil (called TA). In all cases the temperature should be in Celsius. If necessary, convert from Fahrenheit F to Celsius C using the formula C=5/9(F -- 32).
2). Get the conductor dc resistance (RDC) in units of Ohms per foot. This value may be looked up. One ohm per foot equals 3.2808399 m kg s-3 A-2
3). Get the value of the thermal resistance (RDA) between the conductor and the ambient air or soil. The units should be in thermal Ohms per foot.
4). Calculate the ampacity using the values you have obtained in the previous steps. The ampacity I is given by the formula I= squareroot[ (TC -- TA)/(RDC*RDA)] Amperes. This equation is only valid for applied voltages that are less than 2,000 volts and for wires smaller than No. 2 gauge.

Stay informed and read the latest news today from The ThatBiz Online, the definitive source for independent journalism from every corner of the globe.