Example Design
The design process is typically followed as in the steps described below.
Step 1 - Design the main structure of the installation:
At the beginning of the design process we create the basic structure of the installation. This means setting up the distribution circuits, and final circuits downstream from them. When a circuit is added to the installation, the designer sets the type of the conductor, its installation method and its length. For final circuits, the user need specify the type of circuit, along with all of its load parameters. These parameters include the kind, number of points, watts per point or design current, power factor, third harmonic percentage and any diversity factor.
Step 2 - Calculate the maximum demand (and apply load balancing for three phase installations)
After completing step one, the designer is able to calculate the load demand of each distribution circuit and the maximum demand of the installation by applying diversity factors. Also if required the user can specify any spare load percentage to be considered. In case of a three phase installation, at this stage it is appropriate to make changes for load balancing starting from the downstream sub distribution circuits, and moving upstream to the Main Distribution Circuit. The designer can balance the load by moving, swapping or shifting circuits in the distribution circuit so the loads per phase are balanced.
Step 3 - Set the protective devices and calculate the cable sizes
Knowing the demand of each circuit and the maximum demand of the installation, the designer is able to set the appropriate protective devices and then calculate the required cable sizes, starting from the Main Distribution Circuit and moving downstream. Also at this point the designer can set correction factors for the ambient temperature, depth of lay, etc., that eventually will affect the cable size selection.
Step 4 - Resolve warnings and discrimination problems
At this point the user must resolve the critical warnings, and give attention to and resolve warnings related to the discrimination between the protective devices.
Step 5 - Finalize design and print reports
To finalize the design the user may set the frame size per page and draw details or notes.