Im looking to add a circuit to this sub panel box but when I opened it up I noticed that the neutral (black) connection bar is connected to the ground bar, as circled in red in the photo. Is this normal? Also what is the orange wire?
Orange wire looks like Orion NZ Ripple Signal. Used to manage peak load and related things. Have a look over this link: Orion Ripple Signal Guide
As far as the grounded neutral I suspect this is a main panel (nz “switchboard”) and not a sub-panel
Time to hit the books. Consider at least reading through
NZECP 51:2004 ISSN 0114-0663 NEW ZEALAND ELECTRICAL CODE OF PRACTICE FOR HOMEOWNER/OCCUPIER’S ELECTRICAL WIRING WORK IN DOMESTIC INSTALLATIONS