Its possible that taking EC while eating at maintenance will increase your resting metabolism a bit, but the increase won't be significant enough to lose weight/body fat. If your goal is to eat more calories and burn fat, just add in more cardio.
Your body will adjust to EC over a period of time and it will become less effective with prolonged use. I would save EC for when you're trying to cut, preferably toward the end of a cut when fat loss stalls. You can't create a calorie deficit with supplementation alone, it must be done by eating less calories or expending more calories (cardio)