New Zealand defaulted to the Caravan plug commonly referred to as Commando/CEE early on in the EV revolution. These plugs can carry a higher amp rating than the three-pin plug. Advice from WorkSafe and Master Electricians is that these devices should be fitted with an RCD Type B (for detection of DC current) in case of a car side charging fault. DC current going back into a switchboard could be an issue with potential fire risk in the extreme.
DC detection stops that; traditionally we have used an external RCD Type B to mitigate this threat, the issue has been the cost of supply and lack of definitive legal ruling about them. The cost of the device has often been a deterrent (often $600+). We offer 16 Amp portable device with DC detection built-in. Call us for friendly advice if you are not sure. No question is a stupid one