Switchgear selection

Software is being used more and more in the field of optimal selection of switchgear. Each circuit is considered one at a time, and a list is drawn up of the required protection functions and exploitation of the installation, among those mentioned in Figure H22 and summarized in Figure H1.
A number of switchgear combinations are studied and compared with each other against relevant criteria, with the aim of achieving:

• Satisfactory performance
• Compatibility among the individual items; from the rated current In to the fault-level rating Icu
• Compatibility with upstream switchgear or taking into account its contribution
• Conformity with all regulations and specifications concerning safe and reliable circuit performance

In order to determine the number of poles for an item of switchgear, reference is made to chapter G.Multifunction switchgear, initially more costly, reduces installation costs and problems of installation or exploitation. It is often found that such switchgear provides the best solution.