Is it permissible for a construction worker, who works all day under the sun in Ramadan, to break his fast, and is expiation (kaffarah) obligatory upon him, by analogy with the noble verse: "And upon those who are able to it [yet do not fast] – a ransom [for a poor person's meal]"?

Those engaged in arduous work must form the intention to fast overnight. If they suffer harm, they are permitted to break their fast to the extent that alleviates the harm. They must then abstain for the rest of the day and make up the fast later. They should seek work that does not conflict with fasting, and if they cannot find such work, they should take leave or work at night.