I removed my range hood (switched off the electricity for it first) and there are three wires coming out of the wall. There's a white insulated, black insulated, and totally not insulated copper wire. What is the non-insulated copper wire? When I flip the electricity on, will it have a charge? It was weirdly wrapped around a screw in the box with the wiring...I'm not sure if it was doing anything. Thanks!
The copper wire is for ground. If there's a short, it is supposed to send the electricity into metal that leads into the soil. When you flip the switch, no charge should be in the copper wire... unless there is a short. Screw the weirdly-wrapped screw into something metal. If you have a metal utility box, screw it onto that, and you're range will be safe if there is a short.
The bare wire is ground, perhaps the most important wire because it is there for safety. Sure the hood would have worked with out it but you may have gotten electrocuted if it wasn’t connected. Whenever connecting wires in anything the ground wire must be connected. If the box you are connecting the wires in is metal, not only do you have to connect the ground wire to any other ground wires you also have to connect it to the metal box so that the box is grounded. Otherwise later you may come back and touch the box and get electrocuted. The ground wire is there to ensure the breaker/fuse gets tripped if a hot wire touches any metal part of any appliance that is connect in the circuit. If not it will be like touching a hot wire just by touching the appliance. Hope this helps!
