The current-carrying capacity of electric power cables has a significant effect on the total power transmitted from generation bus to the load bus. The capacity decreases as the cable temperature increases. The physics involves a positive feedback effect in which the resistance of the conductor increases as the temperature increases. Observing and predicting the thermal profile of power cables on shipboards will contribute to an efficient, reliable, and robust shipboard power system. An electro-thermal Digital Twin (DT) for predicting and observing the thermal profile of power cables is developed. The developed DT can be used to study the effect of cable temperature on power transmission. The objective of the DT will be to keep the cable temperature below its thermal rating at which deleterious effects occur. The maximum deviation between the physical and digital twin was ±0.7 °C and is well within a reasonable margin of error. Experimental results verify the capabilities of this DT which is ready for integration into larger power system digital twins.