I’m an apprentice - electrocuted under my bosses supervision

[Intoelectrics]

I think the key thing to take from this bad experience is - always do a test yourself, regardless! as much as you may trust someone, they may for what ever reason make a mistake that you or someone else might pay for.

Especially when working on boards like this where there is potentially 400v and lots of exposed conductors. I always, try my tester on a known live source to ensure its working correctly, then at least twice test across all the Phases to each other, to Neutral and to Earth both before and after safe isolation. Those few extra minutes proving its safe could be the difference between life and death!

 

[Midwest]

Continue to speak with your HR, and don't concern yourselves with repercussions. You could suggest you are a 'whistle blower', that gives you rights under law.

Sound like this guy may have developed a cavalier attitude to safety over the years, wake up call for him, and he will probably thank you at a later time, and others that follow you.