3 phase lead-in minimum gauge

[ozgyrex]

Hi guys,

We're starting a build in Queensland of an all electric house and will have some pretty large loads so we're hooking up a 3-phase supply. Some of the large loads include a 22kW 3 phase electric vehicle charger, 3 phase ducted A/C, heat pump pool heater, heat pump HWS, induction cooktop etc.

For the lead-in, is there a minimum gauge cable (according to Australian Standards) that the sparky should be using? I'm struggling to get the builder to answer this question and I've suggested that we'll need at least 63A based on the large loads listed above.

Thanks for your help.

 

[telectrix]

I'dbe looking at 63A per phase as a starter , minimum. more in depth calculation is required if only to save cost of installing an over sized cable.

 

[pc1966]

Rule #1 don't ask a builder about electrics!

This question really will need one of the Australian folks to answer as no doubt the rules differ from the UK.

As @telectrix says you would be looking at a minimum of 63A and here in the UK if you get 3-phase it is normally 100A for domestic supplies. Usually that would require as least 25mm^2 copper cable from a current-carrying capacity point of view, but depending on how the cable is run, and how hot your location is, you might need a larger size to keep the working temperature down.

In addition there are usually regulations on voltage drop, that depends not just on the cable & load, but also on the length of the run so you might find you need heavier cable (beyond CCC value) to avoid excessive voltage drop.

But again, you really should be asking an Oz spark for guidance!