Electrical installation handbook – PART II

Electrical installation

The scope of this electrical installation handbook is to provide the designer and user of electrical plants with a quick reference, immediate-use working tool. This is not intended to be a theoretical document, nor a technical catalogue, but, in addition to the latter, aims to be of help in the correct definition of equipment, in numerous practical installation situations.

The dimensioning of an electrical plant requires knowledge of different factors relating to, for example, installation utilities, the electrical conductors and other components; this knowledge leads the design engineer to consult numerous documents and technical catalogues.

Selection of the cable

The international reference Standard ruling the installation and calculation of the current carrying capacity of cables in residential and industrial buildings is IEC 60364-5-52 “Electrical installations of buildings – Part 5-52 Selection and Erection of Electrical Equipment- Wiring systems”.

The following parameters are used to select the cable type:

Conductive material (copper or aluminium)

The choice depends on cost, dimension and weight requirements, resistance to corrosive environments (chemical reagents or oxidizing elements).

Insulation material (none, PVC, XLPE-EPR)

The insulation material affects the maximum temperature under normal and short-circuit conditions and therefore the exploitation of the conductor cross section (see Chapter 2.4 “Protection against short-circuit”).

Type of conductor

The type of conductor (bare conductor, single-core cable without sheath, singlecore cable with sheath, multi-core cable) is selected according to mechanical resistance, degree of insulation and difficulty of installation (bends, joints along the route, barriers…) required by the method of  installation.