The cable size range for the
56P420 (Australia) or PDL56P420 (New Zealand) plug is 2.5mm2 to 4mm2.

Please go to the website via the following links below and check under the Documentation Tab for more information.
Australia - https://www.clipsal.com/products/detail?CatNo=56P420&itemno=56P420-EO&backto=/search?q=56P420&tab-document-1=0
New Zealand - https://www.pdl.co.nz/products/detail?CatNo=PDL56P420&itemno=PDL56P420&backto=/search?q=56P420