If a man is required to Fard Gusl (Gusl- e-janabat) in the day time of ramadan, how does he do it? It is provided that the man ate sehree and made Niyah for Ramadan. But any..

In the name of Allah, Most Gracious, Most Merciful

Assalaamu `alaykum waRahmatullahi Wabarakatuh

Your fast will not break because of simply requiring a fard ghusl, such as due to a wet dream, for example.  If, however, you did a certain act that necessitates the ghusl, such as sexual intercourse while fasting, then your fast would break (along with requiring kaffārah, in this case). 

It is permissible, rather necessary in your case, to take ghusl while fasting.  You may take your ghusl as normal, except maintain caution and avoid placing water deep in the throat and nose. 

And Allah knows best

Wassalaamu `alaykum

Ml. Abrar Mirza,
Student Darul Iftaa

Darul Iftaa