transformer - A-C delta-wye phase shift

^{simulate this circuit – Schematic created using CircuitLab}

My question is, because the delta primary in this case is connected A-C, rather than A-B, does this effect the direction of the 30 degree phase shift? I have read that if the primary is connected A-B then the primary phase is leading, and if it is connected A-C the primary phase is then lagging the secondary by 30 degrees. Can somebody please shed some light on this for me? I would like to know exactly what is shifting, leading or lagging, and why. Thank you !