I wonder - does a usb c fit into the live side of the plug?

Was the metal box grounded through conduit or did you run a separate ground back to the panel or separate grounded circuit?

Good job! Howd you ground it?

A quick mnemonic device for wiring receptacles:

black guys like gold, white guys like silver..

the black wire goes on the gold lug, the white wire on the silver lug. Green is ground if you've got one. another common mistake- the larger of the 2 slots is the neutral and on any receptacle/plug/whatever the SMALLEST hole or prong or blade is always the one that carries power (black wire).

the reasoning is that you always want to grant the largest surface area/conductor to the white and green wires which take electricity to ground and away from you so that YOU don't become the ground yourself.. when that happens it's what we all think of as "getting shocked".

People who don't know better very commonly miswire receptacles and cords, falsely thinking that the biggest blade/prong/hole must carry the power because.. power big, ground little.. </caveman voice> when actually the reverse is true for some rather abstract safety reasons.

And presumably you're still alive, hence this post! Kudos!

My life has NOTHING to do with electricity and electronics, but one day, I hope it'll have EVERYTHING to do with it. This is so cool!

Is that metal box connected through to your electrical panel via metal conduit? If so, the box itself might be grounded, so you wouldn't need to actually steal the power from your shed. Of course you'd want to test any outlet with the tester you have, but you'd just wire the grounded outlet like normal but w/no ground cable, and make sure the upper/lower metal tabs are screwed tight against the box.

Also, congrats, that's a great achievement!

Is it legal to DIY that if you're not a certified electrician?