Earthing neutral

Much simpler just to have one link, positioned after all the sources, but before any of the loads.

Unless those sources are require an earth for safety reasons - such as at a substation with the transformer primary at HV - in such  a case the secondary earthing link cannot safely be on the load side of any kind of switch, as if left to its own devices it may float up to some sort of mean of the primary voltage . This is more of a problem on single and split phase.

In such a case we quite often do really have 2 NE links, that may be in parallel, but arrange the path that may be shared to be short and fat enough that the full current of both sources could if need be be carried by any one link. Parallel transformer secondary windings are not that common but where it is needed, that is the easiest approach as the design of switched links requires serious thought about credible failure modes, and to be sure all of them are handled.

Much simpler just to have one link, positioned after all the sources, but before any of the loads.

Unless those sources are require an earth for safety reasons - such as at a substation with the transformer primary at HV - in such  a case the secondary earthing link cannot safely be on the load side of any kind of switch, as if left to its own devices it may float up to some sort of mean of the primary voltage . This is more of a problem on single and split phase.

In such a case we quite often do really have 2 NE links, that may be in parallel, but arrange the path that may be shared to be short and fat enough that the full current of both sources could if need be be carried by any one link. Parallel transformer secondary windings are not that common but where it is needed, that is the easiest approach as the design of switched links requires serious thought about credible failure modes, and to be sure all of them are handled.