The whole process

From Electrical Installation Guide

The whole process is described briefly in the following paragraphs and illustrated on Figure D3.

The process described in this document is not intended as the only solution. This document is a guide intended for the use of electrical installation designers.

Fig. D3 – Flow diagram for choosing the electrical distribution architecture

To know more about each step described above, refer to:

Step 1: Choice of distribution architecture fundamentals

This involves defining the general features of the electrical installation. It is based on taking into account the macroscopic characteristics[1] concerning the installation and its usage.

These characteristics have an impact on the connection to the upstream network, MV circuits, the number of MV/LV substation, etc.

At the end of this step, we may have several distribution schematic diagram solutions, which are used as a starting point for the single-line diagram. The definitive choice is confirmed at the end of the step 2.

Step 2: choice of architecture details

This involves defining the electrical installation in more detail. It is based on the results of the previous step, as well as on satisfying criteria relative to implementation and operation of the installation.

The process loops back into step 1 if the criteria are not satisfied. An iterative process allows several assessment criteria combinations to be analyzed.

At the end of this step, we have a detailed single-line diagram.

Step 3: choice of equipment

The choice of equipment to be implemented is carried out in this stage, and results from the choice of architecture. The choices are made from the manufacturer catalogues, in order to satisfy certain criteria.

This stage is looped back into step 2 if the characteristics are not satisfied.


This assessment step allows the design office to have figures as a basis for discussions with the customer and other players.

According to the result of these discussions, it may be possible to loop back into steps 1, 2 or 3.


  1. ^ For example, one characteristic of the installation that will impact the choice of architecture is the expected level of service (availability, reliability ...) of the installation. For more information about downtime prevention, and the latest solutions to mitigate the risks, download the Power Availability and Reliability Guide