My sparky used 4mm^2 cable for my 32A single phase. I did ask for the 6mm, but he said 4 is fine and rated at 32A
32A on 4mm is fine unless you run it inside a wiring enclosure, then it should be derated. even then its on the border so I wouldn't panic. If your sparky says its fine based on the installation methods he adopted then I wouldn't lose sleep.
If you would like to change the charger to 32A then we will need to upgrade your main switch to a current limiting device. We won't charge anything to change the setting for the charger but there will be a cost of $165 incl GST to replace the main switch with a current limiting device.
Ok, so chances are (educated guess) you are limited to 63A single phase in your area by your supply authority. Based on this, they are required to assess or limit maximum demand of your house. They probably have a few calculations back at head office that support them on adding a 25A charger to a typical house, but adding 32A requires either a new calculation which is specific to your house, or as they say you use a circuit breaker to cap the MD. Its not the intended purpose of the circuit breaker but it is a valid method of limiting MD to your installation. I've done the same thing at my house (32A 3 phase to the house with a 25A 3 phase to my charger).
Just be warned, in the 14 months I've had this installed it did trip once, my missus was using the oven and the aircon was on, and we wanted to go for a longish drive that day so I topped up the car. Not a big deal but be aware it can happen. You need to moderate your usage on these rare scenarios. I turned on the power again, got the oven going, aircon on and set the car charging again at 12A (3 phase), once the oven was done I put the car back up to its maximum of 24A 3 phase.
We’ve never had an issue whatsoever in the 4 years charging the cars at 32amps (we’re on single phase etc.)
Just double checked with my electrician (handy having one on call as we do developments) and he said he used a 6mm cable and 40amp rated circuit breaker. He also noted that when we renovated 5 years ago we completely re-wired etc.
Yep, different supply authorities have different allowable maximum demand, if yours is above 70A then depending on the size of your house there is every chance the electrician did assess MD and found it was fine.
Even if you were as low as 63A (fairly low but common allowance) you would not notice any problems as the fuses in your pillar are set higher than that. This will not be a concern for anyone ever until either you exceed your fuse rating, or 10 people in your street also get an EV and you all exceed your MD at the same time potentially causing your supply authority equipment to overheat and suffer damage.
In that event the supply authority has every right to seek damages from the electrician who installed the charger and failed to assess MD. Many electricians are unaware, many electricians see the chances of this event occurring so unlikely that they don't need to worry, but those that are aware and risk averse will insist on what jetcharge have here, and they are within their rights to do so.
. The HPWC is capable of 22 kW (3-phase, 32A per phase), but the on-board AC charger in the Model 3 is 11 kW. So for 3-phase you are unable to dial the charge current higher than 16A inside the car, regardless of the switch setting inside the HPWC.
