In Sydney, Digital Reality opened a site in 2012 out in the western suburb of Erskine Park, almost 40 km from the CBD, but within 3 km of the Transgid Sydney West 330/132kV Substation, one of the key pieces of power supply infrastructure in the Sydney Metro. That facility has 4 separate bays where a tenant can operate a full data center [1].
NextDC is in Macquarie Park, ~10 km from the CBD, and is adjacent to one from Fujitsu and one from Macquarie Telecom.
Siting in these three areas, for example, would confer a decent amount of geographic separation.
[1] https://www.digitalrealty.com/data-centers/sydney/#goto-1718