I think that Eddy has already pointed out that the inverter manual takes into account over-current. Not sure what that inverter is rated at, but I use a 5KW inverter on my lathe which is rated at something like a few seconds at 100% overload and 30 sec at 50% overload. I think that this is probably to allow for motor run-up initial surge, although I'm not driving it that hard. However, let's say max load for a normal Chinese VFD/spindle combination is a nominal 2.2KW, and allowing for conversion inefficiency, that's going to draw maybe 2.5KW from the supply. That's about 10A. Short-term permitted overload is about twice that, which neatly comes out to about 20A - which is where we started!

In real life, though, I would suggest that there are two possible times when the inverter is likely to trip the supply fuse/breaker. One is when you first switch it on. These devices typically rectify the incoming single-phase supply to give a DC supply internally which then drives the 3-phase output generator. There will be a small surge at that time which can give problems. Sometimes the problem is due to funny phase relationships between input current and voltage which can trip RCDs. However, my limited experience with my 2.2KW inverter is that this never happens (although it is a problem for the big inverter I use). Second time it might trip is when the load comes on, i.e. motor startup. However, the inverter is generally set to soft-start the motor - ramp up speed over a few seconds - and that keeps the peak load down. Anyway, you will be spinning up a motor when it is not cutting, so that reduces the load as well.

Upshot of all this in practical terms - it works fine for typical router purposes off a standard 13A socket!