Although I am not in a union, I do work around electricity every day every thing from 12 volts to 480volts AC and DC.
The best advice I can give to someone starting out in the electrical trade.
#1 RESPECT electricity.
#2 Take your time
#3 Most important of all, no matter who tells you the circuit is dead always, always, always, always put a meter on it and test the circuit for yourself before you touch it.
#4 Treat every circuit as if it were live even if power is off.
Good luck in your new career choice. Just don’t rush around electricity