Why neutral is not used in Delta Circuit?

Neutral is to allow a complete close loop system. while ground is to provide low impedance path way for leakage current to the ground, where it would return back to a transformer. I don't plan to use a load directly connected from a phase to ground, scared it may effect other equipment.

in delta circuit there is no need of  neutral becase the the current needs a path to flow which is provided by the corresponding phase. and also delta ckt is usually balanced.

neutral is not used in delta because  for example in high voltage step down transformer.secondary side is connected on earthing. on primary side delta side .it is connected on  power generation side..like high voltage generator is connected in earthing after generator it was connected to transfer and switch gears so that is was already connected on earthing on power generation side

mv generator is earthing ------>switch gear------->transformer(delta side)

Because the line in Delta connection connected to each other in a closed series connection 

In  delta connection, the phasor sum of the three line currents is zero in  balanced and unbalanced loads, then the neutral is not necessary and this is a benefit of the delta connection where voltage drops are less.