What is required of the believer when Ramadan comes is to fast Ramadan. If he is doing difficult work, he should reduce it so that he can fast. He can do that by working in the time that suits him at the beginning of the day, then refraining from the work that is too difficult for him, so that he can complete his fast. Allah, may He be glorified and exalted, has made the fast an obligation and one of the five pillars of Islam.
The Prophet (blessings and peace of Allah be upon him) said: “Islam is built on five (pillars): testimony that there is no god but Allah and that Muhammad is the Messenger of Allah; establishing prayer; paying zakaah; fasting Ramadan; and pilgrimage to the House for the one who is able to do that.”
What is required of every Muslim man and woman is to fast this month, and to beware of everything that may form an obstacle to that. Work does not end and there are many times for it. It is possible for the believer to do his work at night or at the beginning of the day so that it will not be too difficult for him to work in the middle of the day.
The point here is that you have to look for means that will help you to combine the two matters: fasting and working, in a way that will not harm you. This is what you have to do. As for not fasting, that is not permissible for you. End quote.
Shaykh ‘Abd al-‘Azeez ibn Baaz (may Allah have mercy on him)