Sun represents soul, father, government, willpower, vitality, self confidence and ego. As per Vedic astrology Sun is said to be debilitated at 10 degrees in the sign of Libra. The sun is exalted in sign of Aries at 10 degrees, exactly 7 places away from its debilitation sign.
Well, Libra is an air sign and sun represents fire. The air and fire together creates uncontrollable energy, almost like a wildfire and destroys the significance of the house where it's placed.