One of the most important reasons for grounding electrical currents is that it protects your appliances, your home and everyone in it from surges in electricity. If your electrical system is grounded, all of that excess electricity will go into the earth — rather than frying everything connected to your system.
In this way, what does it mean to have a ground wire?
The ground wire is an additional path for electrical current to return safely to the ground without danger to anyone in the event of a short circuit. In that instant, the short would cause the current to flow through the ground wire, causing a fuse to blow or a circuit breaker to trip.
Do Ground wires need to be insulated?
Whether it's bare copper ground wire or HMWPE insulated wire, those working with the electrical circuit can feel safe knowing that a ground is established. It does not have any sort of protective coating, however, the lack of insulation allows bare copper to have the best conductive properties.