The subject of Building Electrical Installations is an important area of ​​electrotechnical applications and one of the main fields of activity for both electrical and technical engineers specializing in electrical engineering, as well as related specialties involved in the subject of building installations in general. Technological advancements, combined with the constantly increasing demand for electrical energy in a modern building installation, require an organized, standardized, and methodical approach to the issue of Building Electrical Installations. This book interprets and analyzes all paragraphs of the Greek standard ELOT HD384, which has regulated electrical installations since the beginning of 2006. With the central axis being the ELOT HD384 standard "Requirements for electrical installations," the rules for the study, design, implementation, inspection, and maintenance of modern building electrical installations are described, while detailed references are made to other standards concerning devices, materials, provisions, and methodologies. Issues such as safety and protection of individuals and equipment, design, implementation, functionality, and control of an electrical installation, as well as topics related to the optimal utilization of electrical energy, are studied and analyzed through examples and with the help of detailed diagrams, charts, and user-friendly tables, always in accordance with the requirements imposed by the applicable specifications. [...]