I have some extra Spindle power cable from my 800W VFD Upgrade Project for sale. It’s 18/4 (3 wire with ground). They had a 50ft minimum order when I bought it. It has NO CONNECTORS on it so you’ll have to solder your own connectors on it yourself. It’s a tight fit but I can share how I did mine with my 800W G-Penny spindle.
I’m recommending it for 800W spindles only as the 1500W and above should be using 16 gauge wire. If you’re interested PM me the length you’re interested in and your zip code and I’ll PM back a price.