AU person here with electric background. 3kw / 240volts is 12.5Amps (average). But the manual clearly states 20Amps. Most AU domestic circuits are 10A for ALL (total burst) outlets on that circuit. Hence the reason for 2 plugs. Even if your workshop had a 15A outlet for welders and such it might still blow the breaker/fuse). So you need to find 2 different circuits on your property. I do NOT recommend touching your main fuse box but there may be some sheet inside which says which rooms are in what circuit. Either way your missus ain't gonna like the extension cords snaking around the house or thru windows so I see a sparky in your future 🔮 Disclaimer: electrics will kill you. Nostr opinions and advise won't protect you from that. Take care.