Applies to electrical installations such as those of: a)residential premises b)commercial premises c)public premises d)industrial premises e)agricultural and horticultural premises f)prefabricated buildings g)caravans, caravan sites and similar sites h)construction sites, exhibitions, fairs and other temporary installations. i)marinas and pleasure craft Covers: a)circuits supplied at nominal voltages up to and including 1000 V a.c. or 1500 V d.c. b)circuits, other than the internal wiring of apparatus, operating at voltages exceeding 1000 V and derived from an installation having a voltage not exceeding 1 000 V a.c., e.g. discharge lighting, electrostatic precipitators c)any wiring not specifically covered by the standards for appliances d)all consumer installations external to buildings; e)fixed wiring for telecommunication, signalling, control and the like (excluding internal wiring of apparatus) f)the extension or alteration of the installation and also parts of the existing installation affected by the extension or alteration. Does not apply to: a)electric traction equipment b)electrical equipment of motor vehicles c)electrical installations on board ships d)electrical installations in aircraft e)public street-lighting installations f)installations in mines g)radio interference suppression equipment, except in so far as it affects the installation's safety h)electric fences i)lightning protection of buildings. This standard is not intended to apply to: -systems for distribution of energy to the public, or -power generation and transmission for such systems. Electrical equipment is dealt with only as far as its selection and application in the installation are concerned. This applies also to assemblies of electrical equipment complying with the relevant standards. An assessment is made of the following characteristics of the installation in accordance with the clauses indicated: -the purposes for which the installation is intended to be used, its general structure and its supplies (clause 31); -the external influences to which it is to be exposed (IEC 60364-5-51); -the compatibility of its equipment (clause 33); -its maintainability (clause 34). Those characteristics shall be taken into account in the choice of methods of protection for safety (see IEC 60364-4-41 to IEC 60364-4-44) and the selection and erection of equipment (see IEC 60364-5-51 to IEC 60364-5-55).