If you know which breaker controls the outlet, turn it off before proceeding. (You can always turn off the main to be extra careful.) Test for power with a non-contact voltage tester, multimeter or ...

GROUND WIRES. Grounding prevents a conductor not meant to carry current ... In a properly grounded system, appliances and metal boxes connect back to the grounding bus of the breaker panel.

The ground wire, like the neutral wire, safely brings electricity back to the breaker box. If electricity cannot reach the neutral wire and there is no safety ground wire, it will seek other ways ...