In North America it is possible to connect a 120v Kapex to a 120v CT, which is supplied with a NEMA 120v 20a plug since this combination should be used with a dedicated 20a 120v circuit. The North America versions of the CT do ship with a adapter cable (sometimes called a "dongel") with a NEMA 120v 15a grounded male plug and NEMA 120v 20a female grounded receptacle.
However, it is not recommended trying to power the combination of Kapex and any CT from a 120v 15 a circuit even when nothing else is powered by that circuit.
In theory and often in practice 50' 12 gauge extension cables are enough power a 20a load, there will be a voltage drop. It is considered far better practice to use 10 gauge extension cables for prolonged use at 50' or longer. Of course these should have proper NEMA 120v 20a connectors on each end and a dedicated 20a circuit should be used.
My own practice is to not power any of my Kapex through a CT, even in my shop where all 120v 20a receptacles are home run to a circuit breaker within 100' using 10 gauge wire. Personally I see no reason to shut off the dust extractor when I finish a cut. Since the NA Kapex are supplied with a NEMA 120v 15a male plug, I connect those to a dedicated 120v 15a NEMA receptacle connected to its breaker home run within 100' with 12 gauge wire. Although in this case the CT does not require a full 20a, I still connect it to a dedicated receptacle as described above.
The two permanently located Kapex in my shop use accelerators for dust extraction. The idea is to provide the same high velocity suction as a Festool CT, yet using the collection capacity of our plant DC system. Those Kapex are powered by dedicated 15a receptacles. Within our shop the two mobile Kapex have dedicated CT22. Those sets are powered by separate circuits.
The Kapex we take on site goes with a new CT36 with the HEPA signs. All of our extension cords longer than 25' are at least 12 gauge. Some of those have grounded 120v 15a NEMA connectors. Others have 120v 20a NEMA connectors. We own no power extension cables smaller than 14 gauge. On sites we do use the Festool supplied dongels when needed.