Is the tenant obligated to repair electrical appliances in a rented house if the landlord refuses to do so, and is he sinful if he leaves the house without repairing them?

The guarantee of leased assets falls upon the lessor, not the lessee. The assets in the lessee's possession are considered a trust and are not guaranteed except in cases of negligence or transgression.

As for maintenance, it is divided into three categories: 1. Ordinary operational maintenance: This is the responsibility of the lessee and pertains to small, non-essential parts that are consumed through use. 2. Regular preventive maintenance: It is permissible to stipulate this upon the lessee if it is clearly defined and quantifiable, as the absence of ambiguity removes the prohibition. 3. Emergency maintenance: This is unanimously obligatory upon the lessor. It is forbidden to stipulate it upon the lessee because it leads to ambiguity in the rent.

If your employer is the lessee, the obligations fall upon them, unless you are acting as their agent or are bound by a contract between you and them. If you undertake maintenance as a voluntary act, you have no recourse. However, if you perform it with the intention of seeking reimbursement, you may seek reimbursement for what was not contractually binding upon you.