Section 250.130(C) applies to both ungrounded and grounded systems. It permits a nongrounding-type receptacle to be replaced with a grounding-type receptacle under the following conditions.
1. The branch circuit does not contain an equipment ground.
2. An existing branch circuit is being extended for additional receptacle outlets.
3. An equipment grounding conductor is connected between the receptacle grounding terminal to any accessible point on the grounding electrode system, to any accessible point on the grounding electrode conductor, to the grounded service conductor within the service equipment enclosure, or to the equipment grounding terminal bar in the enclosure from which the circuit is supplied.
The requirement in 250.52(A)(1) does not permit this separate equipment grounding conductor to be connected to the metal water piping of a building or structure beyond the first 5 ft of where the piping enters the building or structure unless the conditions of the exception to 250.52(A)(1) can be met.
Exhibit 250.49 shows a branch-circuit extension made from an existing installation. This method is also permitted to ground a replacement 3-wire receptacle in the existing ungrounded box on the left, where no grounding conductor is available.
