A sustainable building starts with a fire safe building, which is why it can be argued that fire safety is a sustainable practice. For this reason, the main objective of this thesis is to analyse fire safety in buildings, paying particular attention to electrical systems, which are one of the main causes of fire, due to their large quantity and spread throughout the building. By carefully designing and implementing electrical and electronic communication systems in a workmanlike manner with safe and quality components, the obscuration of rooms invaded by opaque smoke and the spread of gases harmful to people and/or property could be reduced or almost totally eliminated.