Wall plugs or outlets have no top or
bottom. Unlike light switches, it does not matter which way is up
or down. However, most buildings have switch-controlled outlets
mounted upside-down with the center hole on top. Normal position
for plugs is to have the center hole below the two prongs. Very
handy to know when moving into a new place and you want to place a
lamp that you want to be controlled by a light switch.