On a call Saturday, i discovered this improperly installed subpanel.
The handyman had installed a 100 amp sub panel without any conduit between the panels. He also fed the sub panel with only 3 conductors (4 are required) to make matters worse the third wire was a bare piece of ground wire instead of a true neutral. The panel was full of breakers from other manufacturers. Be careful who works on your electrical system, just because an outlet ot light "works" does not mean it is safe.