In this chapter, the following terms have the meanings indicated. Terms Defined. Applicant" means the developer, builder, property owner, or other person, partnership, association, corporation, or governmental agency applying for permanent electric service to new residential buildings or mobile homes. “Commission” means the Public Service Commission of Maryland. “Mobile home” means a dwelling unit constructed for permanent occupancy, which is: Designed for moving along roads and highways by towing with a truck or tractor; and Installed on a permanent foundation. “Person” has the meaning stated in Public Utilities Article, §1-101, Annotated Code of Maryland. “Public service company” has the meaning stated in Public Utilities Article, §1-101, Annotated Code of Maryland. “Residential building” means a structure enclosed within exterior walls or fire walls, built, erected, and framed of component structural parts and designed for single-family occupancy. “Subdivision” means a portion of real property: Which includes or otherwise designates lots or locations intended for residential buildings or mobile homes including “planned unit developments” or “new towns”; and For which a new electric distribution system is required in order to furnish electric service in it. “Underground electric distribution system” means that portion of an electric utility distribution plant necessary to furnish permanent underground service to all present and anticipated residential buildings and mobile homes in a subdivision. The system includes underground electric service lines as defined in §B(9) of this regulation. “Underground electric service line” means that portion of an electric utility distribution plant necessary to furnish permanent underground service from the lot line to a residential building or mobile home. “Utility” means an “electric company” stated in Public Utilities Article, §1-101, Annotated Code of Maryland.