How to use electroCalc
A project contains all the calculations for one installation. In their current form, the calculations are intended for smaller installations, e.g. a residence or smaller industry supplied from a transformer station.
Rnet and Xnet can be used in two ways. Either they represent the network upstream of the transformer station, in which case you select a standard transformer station and low-voltage cables from the transformer's outlet to distribution board A yourself — if you don't know the network's impedance, Rnet and Xnet can be set to 0.0, and the calculation will then use a negligibly small impedance. Or Rnet and Xnet represent the network's impedance including the transformer station, in which case the transformer and LV cable selections should instead be set to '-'.
The installation is built up of five fixed distribution boards — A, B, C, D and E — where the section between two boards is one cable. The first cable is fed from board A and ends at board B, the next runs from B to C, and so on until there are four cables in total, one after another, with E as the last board at the end of the chain. If your installation has fewer than four cables, simply fill in the relevant boards and leave the rest empty. For each board, except the last, you select the protective device for the board as well as the cross-section and the conditions describing how the outgoing cable is installed and loaded.
When a cable meets the requirements, a checkmark is shown. If there is an error, an error message is shown instead, helping you adjust the installation so that it passes. The check is made against HD 60364 and the underlying protective-device data: fuses are based on Siemens data per IEC 60269-3, and for circuit breakers, data is currently only available from Schneider Electric — iC60N for 6-63 A and C120H for 80-125 A. Data for more manufacturers and additional breaker sizes is being added on an ongoing basis.
The cables' installation methods are based on HD 60364-5-52 Annex A, while the check of installation method and current-carrying capacity follows Annex B of the same standard.
The minimum short-circuit current is calculated by default as L-L, but can be changed to L-PE for each cable section. The short-circuit calculations follow the methods in IEC 60909-0, though the transformer's zero-sequence impedance (Z0) is calculated using approximated values.