The layout of AC connections diagrams should be carried out observing the
following points. Each diagram should include all equipment corresponding to a
bay, with breakers, disconnectors and transformers represented by schematic
symbols. In CT current circuits, only the current coils of the measurement instruments
and the protection relays should be drawn, indicating clearly which coils are
connected to each phase and which to the neutral. The polarity of equipment should
be indicated on the drawings. It is useful to indicate equipment whose future
installation can be foreseen by means of dotted lines.