4.0 A pickup will operate only if the current through the relay is 4 A or greater. This pickup value
is determined by the application of the relay and must be available on the specific relay type being
used. The setting is first calculated considering the maximum load and minimum fault currents in
terms of the primary current and then, using the CT ratio, the secondary current is calculated. It is
then specified in terms of the pickup of the relay being used so the relay can be set and calibrated.