Grounding electrical circuits is a safety practice that enables electricity to take an alternate path back to the breaker box when an electrical device or appliance short circuits. Without a grounding path, the current would flow through someone that was holding the
appliance. The grounding wire in a circuit is connected to the third pole in a typical household receptacle.
The grounding wire in this power drill connects to the third prong on the plug and the drill's metal case. This connection is tied back to the breaker box and subsequently to a grounding rod driven deep into the ground.
In the event of a short circuit, the electricity can follow two available paths. The easy path is through the case of the drill and the grounding wire to the breaker box. The harder path is through the person using the drill. Without the grounding wire, the current would flow through the person using the drill since there is no other possible path for the current to follow. This could be catastrophic.
