In my building where I am Secretary I was contacted by NBN prior to installation seeking OC permission. I had to sign forms agreeing to the work and attesting that I had the authority to sign for the OC.
One submitted the work proceeded using some of the existing Foxtel cabling and box. Then the installers of the NBN box either used existing Foxtel points or at a mutually agreed and reasonable point in the unit.
There were no external changes to the building for the installation of the NBN box in each unit. This box is only installed when the owner chooses to engage an NBN RSP.