The article presents an overview of the approach to the technical design for the electrical and low voltage systems specialty, starting from the phase of current situation analysis and concept(s) development, until the implementation phase. Design is an important link in the chain that forms any “re-” process (restoration/conservation, rehabilitation, renovation, revitalisation, reconversion, recovery, repurposing, reconstruction) of the built heritage. For the result to be the one desired by everyone, i.e. the implementation works to have a high level of quality, the technical design must have an appropriate technical content and has to be implemented by a specialised team approved for interventions on historic buildings. The article is structured in three parts; thus, it opens with an introduction, followed by an incursion into the design stages of electrical and low voltage systems, highlighting the role of the stages, as well as of its protagonists, and closes with a brief conclusion.