N.C. Gen. Stat. § 58-3-15
No insurance company or insurance producer licensed to do business in this State may issue any policy or contract of insurance covering property in this State that contains any clause or provision requiring the insured to take or maintain a larger amount of insurance than that expressed in the policy, nor in any way provide that the insured shall be liable as a coinsurer with the company issuing the policy for any part of the loss or damage to the property described in the policy, and any such clause or provision shall be null and void, and of no effect: Provided, the coinsurance clause or provision may be written in or attached to a policy or policies issued when there is printed or stamped on the declarations page of the policy or on the form containing the clause the words "coinsurance contract," and the Commissioner may, in the Commissioner's discretion, determine the location of the words "coinsurance contract" and the size of the type to be used. If there is a difference in the rate for the insurance with and without the coinsurance clause, the rates for each shall be furnished the insured upon request.
N.C. Gen. Stat. § 58-3-15