Reply by EEngineer

Just a quick note:

This will not work if you have GFCI protected circuits. GFCI works by comparing the currents in the “hot” and “neutral” and tripping if there is any difference between them. This little trick allows current to flow from one “hot” to the other “hot” with no neutral return current.

Recent NEC requires GFCI protection in attached or detached garages, so if you have a garage shop and your house is fairly recent, you have GFCI.

I am currently (pun intended) rewiring my detached garage shop and have spent way too much time with the NEC lately.

-- "Find out what you cannot do and then go do it!"