Is it permissible to combine prayers when not traveling, given theقطع water and electricity, and the nature of the work that requires changing clothes and continues most of the time?

Combining two prayers that share a time is not permissible in all circumstances; rather, it is a concession granted for certain reasons mentioned in Fatwa (definition) no. 33182. The interruption of water or electricity is not a valid excuse that permits this combination, and this has been detailed in Fatwa no. 56502. There is no objection to praying in work clothes that are not clean, provided they are pure. However, it is preferable to wear the most beautiful garments as a sign of reverence for the rituals of Allah. For details, please refer to Fatwa no. 37887.