I'm encountering a situation where I'm installing a Electric Water Heater in basement and there's a existing unused out for 240 (30 Amp) available right in room above.
Unit specifications are to use 12/2 guage with 20 Amp, independent circuit.
Running a new line is bit of work until is must. Connecting 12 guage to 10 guage with 30 amp is not safe either. Any suggestions would be awesome.