“manufactured home construction” means all activities relating to the assembly and manufacture of a manufactured home including but not limited to those relating to durability, quality, and safety;

“retailer” means any person engaged in the sale, leasing, or distribution of new manufactured homes primarily to persons who in good faith purchase or lease a manufactured home for purposes other than resale;

“defect” includes any defect in the performance, construction, components, or material of a manufactured home that renders the home or any part thereof not fit for the ordinary use for which it was intended;

“distributor” means any person engaged in the sale and distribution of manufactured homes for resale;

“manufacturer” means any person engaged in manufacturing or assembling manufactured homes, including any person engaged in importing manufactured homes for resale;

“manufactured home” means a structure, transportable in one or more sections, which, in the traveling mode, is eight body feet or more in width or forty body feet or more in length, or, when erected on site, is three hundred twenty or more square feet, and which is built on a permanent chassis and designed to be used as a dwelling with or without a permanent foundation when connected to the required utilities, and includes the plumbing, heating, air-conditioning, and electrical systems contained therein; except that such term shall include any structure which meets all the requirements of this paragraph except the size requirements and with respect to which the manufacturer voluntarily files a certification required by the Secretary and complies with the standards established under this chapter; and except that such term shall not include any self-propelled recreational vehicle;