I don’t intend on going with a 50 amp breaker, I just want to feed off of the exsisting 30 amp breaker in my garage panel which is apparently a sub panel since the main breakers are on the outside of the house near my meter. I want to run a 3 prong dryer cord 10 gauge from my dryer outlet to a spa panel which has a 50 amp GFCI. The reason this would work for me is because the sub panel in my Garage is full and all the outlets in my garage are 15amp and like I mentioned previously for portability. When We’re not using the dryer I can plug in the sub panel and do what I need. Having the sub panel setup properly with 4 wire would enable me to run a heating element so I can continue to brew beer, enable me to use my welders and possibly add another circuit off the spa panel to run a couple 20 amp breakers for power tools and whatever else in the garage. When I was in Germany I ran a 3500 watt element off my kitchen outlet 220v with an auber pid with no issues, I loved it and would like to adapt that at my new place. I appreciate the advice and replies, sorry again for the confusion!