Final answer:
It is recommended to use a heavier gauge copper (K or L) when tubing will extend through concrete because it offers more durability, minimizes the risk of corrosion, and matches the resistance per length of the wires.
Step-by-step explanation:
It is recommended to use a heavier gauge copper (K or L) when tubing will extend through concrete. This is because the heavier gauge copper has a thicker diameter and therefore offers more durability and strength, making it less likely to be damaged during the installation process and while being embedded in concrete.
Using a heavier gauge copper also helps to minimize the risk of corrosion. Copper is more resistant to corrosion compared to other metals, such as iron, and using a heavier gauge ensures that the copper tubing will last longer when exposed to the elements, including the alkaline nature of concrete.
Furthermore, the larger diameter of the copper tubing helps to match the resistance per length of the wires. This is important for electrical applications as it ensures that the current can flow more efficiently through the copper tubing, reducing power losses and maintaining electrical performance.