USB power supply puts 220 Mains power out on USB jack
If you are wondering "How could an isolation transformer ever get past QC with abraded or nicked insulation?", you might find this video interesting:<p><a href="https://www.youtube.com/watch?v=HEJn74Z3wHk" rel="nofollow">https://www.youtube.com/watch?v=HEJn74Z3wHk</a>