The earth or the ground is the reference point in an electrical circuit from which voltages are measured. Grounding gives electricity an efficient way to return to the ground by way of the service panel. The electrical current flows from the panel to the device that needs to be powered up, with the neutral or third wire acting as the return path to the ground for any unused current. The ground wire serves as an additional path through which electrical current can safely return to the ground without posing any danger in the event of a short circuit. When a short circuit occurs, the electrical current will flow through the ground wire, blowing a fuse or tripping the circuit breaker.
Ground wires on power tools and portable devices are safer when they incorporate a third prong, which is a ground connection. When there is a polarized plug and the outlet has no ground, the third prong of a power tool or an extension cord is often cut.
Ungrounded electrical devices are dangerous. Because they lack a ground path, the person holding the device will act as the ground path and may experience electric shock or electrocution. This is the reason appliances and devices today come with three-pronged cords, which include a wire for ground protection.
For grounding to be effective, it has to produce less resistance than a human being. Any resistance to the current will obstruct flow and increase the risk of electrocution. To keep resistance low, the ground impedance must be less than 1 ohm.
To further ensure safety, a pigtail connection can be used to connect multiple wires to a screw terminal. Pigtails are insulation displacement connectors filled with dielectric grease that prevent moisture from getting inside the connector.
A contract electronic manufacturer should improve the safety of the devices they produce by incorporating grounding that will prevent electric shock or electrocution.