Suffix ‘N’ is generally used in preference to ‘G’ for devices that are connected in the secondary of a current transformer whose
primary winding is located in the neutral of a machine or power transformer. ‘N’ may also be used for devices connected in
the residual circuit of the three secondary windings of the CTs connected in the primary as shown in Figure 7.12. However, if
there are relays in both the neutral connection to ground and the residual circuit of the three phase CTs, it is common practice to
differentiate between these two sets of relays by designating one ‘N’ and the other ‘G’. In the case of transmission line relaying,
the suffix ‘G’ is used for those relays that operate on ground faults, regardless of the location of the CTs.