I'm not a licensed electrician, but here's how it was explained to me by a licensed electrician:
There should be only one ground point in your home's electrical system. More than one can cause a ground loop potential. The only other time you would need to drive another copper rod into the ground would be for a roof antenna, and that's to direct atmospheric static/lightning to the ground.
Electrically, the power comes to your house on 3 wires, 2 hot (each 110 volt), the other neutral. The neutral gets connected to the ground lug on your meter pan and the ground/neutral bus bar in your service panel (circuit breaker box). The ground/neutral bus bar also gets bonded (connected by strap) to the cabinet of the service panel. Two forms of earth ground now get connected to the ground/neutral bus bar of the service panel, one appropriately sized wire to the water main where it enters the building, the other to a copper ground rod driven into the ground. I would have to check the current National Electric Code book to see what's done if your water main is PVC.
Every circuit needs to be complete to work. Power coming from the electric company on those hot wires still has to return to the power station for the circuit to be complete. Believe it or not, in some places, it travels though the ground. That's why they call it an earth ground.
All outlets in the house should have the same grounding point; that is to the original neutral/ground bus bar in the service panel. If you run a sub-panel from the main service panel, it too gets it's ground from the same ground/neutral bus bar in the primary panel, you don't ground it to another earth driven rod or more local pipe.
Any structures outside that could be electrified such as a metal fence, swimming pool, or pool pump must also be bonded to the main panel.
All outlet boxes, switch boxes and wires in metal junction boxes get connected back to the original ground as well.
If your house has copper hot/cold water plumbing, a bonding strap is placed at the hot water heater between the cold in and hot out water pipes to maintain continuity between the hot and cold water lines as they become physically separated inside the tank. Example why- if an energized bare wire were to contact an ungrounded hot water line, the hot water line would become energized too. Same kind of recipe for disaster can occur outside, if a bared extension cord were to energize an ungrounded metal fence, the fence would become energized.
In a 110 volt circuit, the black wire is hot, the white wire is neutral and the bare or green wire is ground. The circuit is completed when power flows from hot to neutral once the switch is thrown. The purpose of the ground is to trip the breaker supplying the circuit should any exposed metallic surface (switch box, outlet box, junction box, copper pipe) become energized accidentally; short circuit to ground trips breaker.
Let me give you an example of a near disaster I experienced at my brother's house. He had an outside flood with the hot and neutral wires reversed and no ground. In his situation, the metallic housing for the light became energized by a bared hot wire. Since polarity of the circuit had been reversed, the switch was on the neutral wire rather than the hot wire, and the exposed housing was always energized, even when the switch was in the off position. Had a proper ground been in place, the circuit breaker would have tripped off as soon as it was turned on, because power would flow straight back to ground, a short circuit condition tripping the breaker.
The answer to your question should be you shouldn't need another ground rod if one is already in place. If not, it should run from the neutral/ground bus bar in the primary panel on an appropriately sized wire. If you were to drive another copper rod into the ground, it must be connected to the main panel's ground bus bar. I personally don't see a problem having multiple insertions into earth ground, as long as they are all connected to the same bus bar of the service panel.
If you have a dedicated circuit, make sure it is properly grounded back to the service panel. If it's coming from a sub panel, make sure the sub panel has been properly grounded as described above.
If you connected your dedicated outlet to it's own ground rod and a short occurred, your breaker might not trip so fast. Current will run to ground using the path of least resistance. Imagine what would happen if you took just a hot (black) wire from your neighbor's circuit panel and completed the circuit using the ground and neutral wires from your panel. If a short occurred, your neighbor's circuit breaker might never even trip.
There should be only one ground point in your home's electrical system. More than one can cause a ground loop potential. The only other time you would need to drive another copper rod into the ground would be for a roof antenna, and that's to direct atmospheric static/lightning to the ground.
Electrically, the power comes to your house on 3 wires, 2 hot (each 110 volt), the other neutral. The neutral gets connected to the ground lug on your meter pan and the ground/neutral bus bar in your service panel (circuit breaker box). The ground/neutral bus bar also gets bonded (connected by strap) to the cabinet of the service panel. Two forms of earth ground now get connected to the ground/neutral bus bar of the service panel, one appropriately sized wire to the water main where it enters the building, the other to a copper ground rod driven into the ground. I would have to check the current National Electric Code book to see what's done if your water main is PVC.
Every circuit needs to be complete to work. Power coming from the electric company on those hot wires still has to return to the power station for the circuit to be complete. Believe it or not, in some places, it travels though the ground. That's why they call it an earth ground.
All outlets in the house should have the same grounding point; that is to the original neutral/ground bus bar in the service panel. If you run a sub-panel from the main service panel, it too gets it's ground from the same ground/neutral bus bar in the primary panel, you don't ground it to another earth driven rod or more local pipe.
Any structures outside that could be electrified such as a metal fence, swimming pool, or pool pump must also be bonded to the main panel.
All outlet boxes, switch boxes and wires in metal junction boxes get connected back to the original ground as well.
If your house has copper hot/cold water plumbing, a bonding strap is placed at the hot water heater between the cold in and hot out water pipes to maintain continuity between the hot and cold water lines as they become physically separated inside the tank. Example why- if an energized bare wire were to contact an ungrounded hot water line, the hot water line would become energized too. Same kind of recipe for disaster can occur outside, if a bared extension cord were to energize an ungrounded metal fence, the fence would become energized.
In a 110 volt circuit, the black wire is hot, the white wire is neutral and the bare or green wire is ground. The circuit is completed when power flows from hot to neutral once the switch is thrown. The purpose of the ground is to trip the breaker supplying the circuit should any exposed metallic surface (switch box, outlet box, junction box, copper pipe) become energized accidentally; short circuit to ground trips breaker.
Let me give you an example of a near disaster I experienced at my brother's house. He had an outside flood with the hot and neutral wires reversed and no ground. In his situation, the metallic housing for the light became energized by a bared hot wire. Since polarity of the circuit had been reversed, the switch was on the neutral wire rather than the hot wire, and the exposed housing was always energized, even when the switch was in the off position. Had a proper ground been in place, the circuit breaker would have tripped off as soon as it was turned on, because power would flow straight back to ground, a short circuit condition tripping the breaker.
The answer to your question should be you shouldn't need another ground rod if one is already in place. If not, it should run from the neutral/ground bus bar in the primary panel on an appropriately sized wire. If you were to drive another copper rod into the ground, it must be connected to the main panel's ground bus bar. I personally don't see a problem having multiple insertions into earth ground, as long as they are all connected to the same bus bar of the service panel.
If you have a dedicated circuit, make sure it is properly grounded back to the service panel. If it's coming from a sub panel, make sure the sub panel has been properly grounded as described above.
If you connected your dedicated outlet to it's own ground rod and a short occurred, your breaker might not trip so fast. Current will run to ground using the path of least resistance. Imagine what would happen if you took just a hot (black) wire from your neighbor's circuit panel and completed the circuit using the ground and neutral wires from your panel. If a short occurred, your neighbor's circuit breaker might never even trip.