An ROI is required if a registered electrician has done work on the mains supply, the switch board or the earth system on your property. Anything related to the main power supply or distribution system within an installation must be independently inspected by a qualified electrical inspector.
EWOF's are required for Mobile Homes, Portable Cabins, Caravans and Campervans, and are a requirement of law in New Zealand for all mobile buildings and vehicles designed to be connected to the 230 volt supply system. EWOF's are valid for 48 months from the date of issue.
An EWOF is provided by an electrical inspector and is required prior to connecting your Caravan or Campervan to the power supply and requires renewal every 48 months.
CoV's are generally required for properties or connections that have been "off the grid" (i.e. disconnected) for six months or more. they validate safety to reconnect and are usually required by banks, insurance companies and electricity retailers prior to reconnection, and also for pre-purchase of a property.
CoC's are issued by an electrician when electrical work occurs. A CoC documents and describes the work carried out and is issued prior to connection to valid that the work done is safe and compliant. In addition depending on the work done a CoC may also require an independent electrical inspection be carried out, and the work be signed off by a registered electrical inspector as well as the electrician.