Why can’t a separate ground wire from a water pipe to the outlet box be run in an ungrounded system to allow installation of a grounded receptacle outlet?
The NEC has strict rules for ground wires where they can be connected and how. Installing a separate ground wire may be possible if all conditions are met. Explanation: The NEC states that the equipment grounding conductor of a grounding-type receptacle outlet shall be connected to: • Any accessible point on the grounding electrode system. • Any accessible point on the grounding electrode conductor. • The equipment grounding terminal bar in the enclosure where the outlet branch circuit originates. • For grounded systems, the grounded service conductor within the service equipment enclosure. • For ungrounded systems, the grounding terminal bar within the service equipment enclosure.The grounding electrode system can consist of the underground metallic water piping system, but the grounding electrode conductor must be connected to the piping within five feet of where it enters the building. The NEC states that metal interior water piping located more than five feet from the entrance into
