Adding an external socket in New Zealand (Ed.)

[wondernz]

I have an existing exterior single 10a power socket and I want to change it to a double 16a power socket and run new cable to a sleepout I have which is all using 16a, is this a simple to do or do I need special cable etc?

 

[FrodoOne]

I have an existing exterior single 10a power socket and I want to change it to a double 16a power socket and run new cable to a sleepout I have which is all using 16a, is this a simple to do or do I need special cable etc?

(Hopefully, you mean "run an Extension Lead [not a "new cable"] to a sleepout".)

One does not use 16 A Socket-Outlets in Australia/New Zealand.
The usual Socket-Outlets are (normally) rated at 10 A.
However, 15 A, 20 A, 25 A and 32 A Socket-Outlets are "available".

The FIRST thing that you need to do is to
look-up the PDF File, with the rather long winded title of
"NEW ZEALAND ELECTRICAL CODE OF PRACTICE FOR HOMEOWNER/OCCUPIER’S ELECTRICAL WIRING WORK IN DOMESTIC INSTALLATIONS",
and
download it.

Having done that
try to understand that which it tells you (on Page 24 etc.)

The "Power" Cables used have 2.5 mm² conductors and are "rated" at 20 A.
Hence you may connect one (or more) 10 A, 15 A or 20 A Socket-Outlet to one of these cables.

If the "Exterior" Socket-Outlet looks like this Single 10 A socket-outlet pictured in
https://www.starsparky.com.au/cdn/s...-b9a1-9c80dabec97d.png?v=1624946250&width=493
change it for a Double "Socket-Outlet",
such as this Dual 15 A Socket Outlet

Clipsal WSC227/2/15-RG

However, why do you "need" more than 10 A?

Externally, 15 A is "usually" used only for Caravans and "Mobile Homes".

15A "Extension Leads" (for Caravans etc.) are readily available.
(https://www.bunnings.co.nz/hpm-20m-15a-extra-heavy-duty-industrial-extension-lead_p0248221 )