Legislation concerning electrical work you are allowed to do in your home can be found here http://www.legislation.govt.nz/regulation/public/1997/0060/latest/DLM229444.html]http://www.legislation.govt.nz/regulati ... 29444.htm Disclaimer: Inexperience & improper wiring is dangerous and can cause fire, personal injury or death. With electricity, there's no room for errors. In some cases it may also void your insurance if not compliant. Water and electricity do not mix The FNZAS recommends getting any electrical wiring work around your aquarium done by a suitably qualified person. IN SHORT FORM You are allowed to remove and replace light fittings, cords, etc, this does not mean you are allowed to DIY new fittings from scratch. You are allowed to install new or extent sub circuits, PROVIDED they are inspected and signed off by a qualified sparky. Replacing a plug or broken bulb holder is fine but building new fittings is not.