This part of IEC 61936 provides common rules for the design and the erection of electrical power installations in systems with nominal voltages above 1 kV a.c. and nominal frequency up to and including 60 Hz, so as to provide safety and proper functioning for the use intended.

For the purpose of interpreting this standard, an electrical power installation is considered to be one of the following:
a) Substation, including substation for railway power supply
b) Electrical installations on mast, pole and tower Switchgear and/or transformers located outside a closed electrical operating area
c) One (or more) power station(s) located on a single site The installation includes generators and transformers with all associated switchgear and all electrical auxiliary systems. Connections between generating stations located on different sites are excluded.
d) The electrical system of a factory, industrial plant or other industrial, agricultural, commercial or public premises
e) Electrical installations erected on offshore platforms e.g. offshore wind power farms.
The electrical power installation includes, among others, the following equipment:

• rotating electrical machines;
• switchgear;
• transformers and reactors;
• converters;
• cables;
• wiring systems;
• batteries;
• capacitors;
• earthing systems;
• buildings and fences which are part of a closed electrical operating area;
• associated protection, control and auxiliary systems;
• large air core reactor.

NOTE In general, a standard for an item of equipment takes precedence over this standard.
This standard does not apply to the design and erection of any of the following:

• overhead and underground lines between separate installations;
• electric railways;
• mining equipment and installations;
• fluorescent lamp installations;
• installations on ships according to IEC 60092 [34] series and offshore units according to IEC 61892 [35] series, which are used in the offshore petroleum industry for drilling, processing and storage purposes.
• electrostatic equipment (e.g. electrostatic precipitators, spray-painting units);
• test sites;
• medical equipment, e.g. medical X-ray equipment.

This standard does not apply to the design of prefabricated, type-tested switchgear and high voltage/low voltage prefabricated substation, for which separate IEC standards exist.

This standard does not apply to the requirements for carrying out live working on electrical installations.

If not otherwise required in this standard, for low-voltage electrical installations the standard series IEC 60364 applies.