The Electrical work that home owners may do themselves is controlled by the New Zealand Electricity Regulations 1997.
This is an extract from the Regulations, if in any doubt contact Energy Safety:
PO Box 165 Free-phone (NZ only): 0800 030 040
Electricity Regulations 1997
Home-owners' electrical wiring work
(1)For the purposes of section 110 of the Act, any person to whom that section applies may do or assist in doing the following work on low voltage electrical installations:
(2)A person who carries out work pursuant to section 110 of the Act must carry out the work in accordance with the requirements of ECP 51.