This standard applies to the design and execution of electrical installations, in particular for penetrations and connections in the area of the airtight layer and for connections in or on the windproof layer in residential buildings (for example collective housing, terraced houses, single-family houses) as well as electrical installations outside the buildings which are connected to these. It also applies to existing buildings, depending on the initial situation and the objective of modernization. This standard also applies to residential buildings with partial commercial use and to buildings with comparable electrical equipment requirements. Electrical installations in residential buildings are: - low-voltage installations with nominal voltages up to 1 000 V; - information and communication technology (ICT) installations, domestic communication installations and other signalling and information processing installations; - radio and communication technology (BCT) installations and interactive services with or without connection to a generally accessible network of a network operator; - lightning protection systems. This standard has been prepared by Working Committee NA 005-09-85 AA "Electrical installations in residential buildings" at Standards Committee Building and Civil Engineering (NABau) at DIN.