You can sue the seller for fraud and the home inspector for negligence.Fraud is the intentional misrepresentation or nondisclosure of a material fact made with knowledge of its falsity and with the intent to induce your reliance upon which you justifiably relied to your detriment.In other words, you would not have bought the house had you known  the wiring was not copper.Your damages (monetary compensation you are seeking in your lawsuit for fraud) would be either the benefit of the bargain or your out of pocket loss.Benefit of the bargain means a defrauded purchaser may recover the difference between the real and represented value of the property regardless of the fact that the actual loss suffered might have been less.Out of pocket determination of damages for fraudulent misrepresentation permits recovery of the difference between the price paid and actual value of the property acquired.Your lawsuit against the inspector would be for negligence, which is the failure to exercise due care (that degree of care that a reasonable home inspector would have exercised under the same or similar circumstances to prevent foreseeable harm).  Your damages for negligence would be what the negligence caused such as costs incurred if the wiring is replaced.You would file one lawsuit naming the seller, home inspector, and home inspection company (inspector's employer) as defendants.