For a 1-HP ACU, what should be the appropriate size of the wire/cable?

The appropriate size of wire or cable for a 1-HP air conditioning unit (ACU) depends on the electrical current it draws and the capacity of the wire to handle that current safely without overheating.

A 1-horsepower (HP) AC unit typically requires about 746 watts of power. When converted to amperage, depending on the voltage of your system (usually 230V for residential applications), you can estimate the current draw. For instance, at 230V, the amperage would roughly be around 3.25 amps. However, taking into consideration factors such as starting current (inrush current) and possible efficiency losses, it is essential to select a wire size that provides a safety margin.

The 5.0 square mm cable rated for 30 amps offers a significant overcapacity, ensuring that the wire remains within safety limits even during surges that may occur when the unit starts. This thicker wire reduces the risk of overheating and voltage drop across the cable. The higher ampacity also allows for safe operation without compromising the functionality of the AC unit or the electrical installation.

Ultimately, while smaller wire sizes may technically carry the load, they do not provide the same level of safety and efficiency under varying operational conditions.