Why do they hang hydro cables a little instead of being stretched?

Hydro cables are hung with a slight sag instead of being tightly stretched to accommodate thermal expansion and contraction due to temperature changes. This sag helps prevent excessive tension that could lead to cable breakage or damage due to wind, ice, or other environmental factors. Additionally, the slack allows for movement and flexibility, reducing stress on the support structures. Proper sag also helps maintain the cable's electrical properties and safety standards.