Jackson wrote:
"Em" was just pondering this little gem:
I added a light fixture to an existing 20A 12awg circuit, and didn't
realize I used 14awg romex until I was done. The new fixture wouldn't
overload even a 15A circuit, so a) are you gonna tell me I have to
fix my error and put in the larger cable,

YES!

and b) why is that?

So you can sleep at night?


What if he turns off the light at night? Could he sleep then?