When Qadha and Kaffarah Is obligatory

1725. If a person who is fasting in Ramadhan vomits intentionally, he/she must give the Qadha of that day only and if he enters state of Janabat at night and as described in article (1696) wakes up three times and sleeps and remains sleep until Fajr Adhan, or does enema intentionally or immerses his/her head in water, or ascribes a lie to Allah or the prophet (ASW), as an obligatory precaution, he must give Kaffarah, and if he invalidates his fast by other acts intentionally and knowing that it will invalidate fast, Qadha and Kaffarah are both obligatory for him.

1726. If one does not know the rules and performs an a ction which invalidates fast, if he could have learnt the rules, as a precaution, he must give Kaffarah, and if he could not have learnt or did not know the rules at all or he was sure that it will not invalidate fast, Kaffarah is not obligatory for him.

Kaffarah for Fast
When only Qadha of Fast is obligatory
Rules of Qadha Fasts