An electric utility, affiliated transmission company, or independent transmission company shall not begin construction of a major transmission line for which a plan has been submitted under section 4 until the commission issues a certificate for that transmission line. Except as otherwise provided in section 9, a certificate of public convenience and necessity under this act is not required for constructing a new transmission line other than a major transmission line or for reconstructing, repairing, replacing, or improving an existing transmission line, including the addition of circuits to an existing transmission line.