I really think we have problems with technical terms different on both sides of the pond.
An "IEC-neutral" is connected to the star point of a transformer or genny. Almost always this constellation provides two different voltages A(V)= 1,73 *B(V) with three phases at 120°, although sometimes only on e voltage is used. Any conductor between this star point and a load is practically called "neutral" <>AE:~ grounded conductor.
So if your switchbord is running on two voltages you can't use a delta supply.
Let's assume your installation is running on just one voltage, then no neutral is necessary. Maybe it is like that in your case.
Next thing is protection when faulty. For this different systems/philosophies exist.
These will be described by the TN, TT or IT letter combinations.
Let's assume you need one voltage, but the philosophy ist TN. Then you will have to connect the gr/ye PE conductor to the star point AND to the ground. No star point ->no TN. If the short circuit current is sufficient, no RCD (~GFI) is necessary, otherwise yes.
Let's assume you need only one voltage, but the philosophy ist TT. Once more: no star point -> no TT. The star point and PE conductor are grounded separately. RCD is mandatory. In a local system like yours possible, but doesn't make sense from a German point of view.
Let's say you're philosophy is IT. Then no star point is necessary. Protection becomes a bit more complicated.
At this point I'd like to know whether it makes sense to continue? Did I get your point?
BTW: all other configurations like open deltas and corner grounded deltas or other weird stuff are extremely uncommon.
