Reddit reviews 14-30P 4-Pin Male Dryer Plug To 6-15R 3-Prong Female Socket Receptacle Outlet Electric Power Cord Cable Adapter/Converter NEMA 220/250V input 220/250V Output. FX837
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So for 240V it's two 120V lines in parallel. A dryer outlet should be 240V 30A with two 120V lines (red and black), a neutral (white), and a ground (green). The Foundrywired for 240V with the correct fuses, as seen in the manual will be two 120V lines and a ground. My guess is you'd need something like this with a male adapter end like this on your Foundry.
If you can get the correct ends you could make all these yourself relatively easily. However, I'd only say to do that if you're comfortable working with electrical components yourself. Also I'm not an electrician, but I did wire up my DIY brewery and have converted a table saw from 120V to 240V so I do have a bit of experience with it.