A building, structure, or lot, except a mobile home, which does not conform to the provisions of this chapter, other than Article
IV, §
300-16, Table of Use Regulations, and which is not involved in a nonconforming use, may be altered, replaced, reconstructed or enlarged, provided that its nonconformity is not increased by such alteration, replacement, reconstruction or enlargement. This subsection shall not apply to any building or structure which contains a nonconforming use. Such a building or structure, except a mobile home, shall be governed under Subsection
C hereof. No mobile home shall be altered, replaced, reconstructed or enlarged under any circumstances.