Is it permissible to use the workplace's electrical outlet for making tea and coffee, and to use the work phone for private calls?

It is forbidden for an employee to use government tools for personal purposes, as this constitutes a breach of trust. This includes benefiting from electricity, paper, photocopiers, and the like, unless the benefit derived is from something insignificant that causes no harm or change, such as a ruler, or if the competent authority has granted the employee permission to do so.