Wiring A Switch For A 240v Power Outlet
A single receptacle has to be full circuit amperage [NEC 210.21(B)(2)], so the 15A (NEMA 6-15) receptacle would be connected to 15A breaker or you need a NEMA 6-20 or a duplex 6-15. Normally a 6-20R is a T-slot and will accept a 6-15P.
Also the 2020 NEC specifies 240v receptacles in garages now require GFCI protection too [210.8(A)(2)].