Extending branch circuits off of ungrounded systems,
2 wire system no equipment ground.
Chelan Home Inspections
Dealing with older wiring systems can be a bit tricky for new homeowners and those who live in these older homes. Often in older homes (Pre-early 1960’s), we have ungrounded wiring systems and often fewer receptacles than what we are used to in more modern homes (What is a Sufficient Number of Receptacles? A historical review). So how do we deal with this? What can I and what can’t I do to add new receptacles and extend branch circuits?
So the question came up can you extend an ungrounded branch circuit without a grounding conductor?
Or, can you extend an ungrounded circuit without an equipment grounding conductor as long as you provide GFCI protection and mark it “GFCI Protected, No Equipment Ground”?
Well, the answer to both of these questions is “NO” . When extending circuits we need to now upgrade to grounding.
From the NEC Handbook-
Section 250.130(C) applies to both ungrounded and grounded systems, but its most common application is for receptacle replacement of branch-circuit extensions in single-phase, 120-volt, 15- and 20-ampere branch circuits, which are required to be supplied by a grounded system per 250.20(B). This section permits a non-grounding-type receptacle to be replaced with a grounding-type receptacle under the following conditions:
The branch circuit does not contain an equipment ground.
An existing branch circuit is being extended for additional receptacle outlets.
An EGC is connected from 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, to the equipment grounding terminal bar in the enclosure from which the circuit is supplied, or to an EGC that is part of another branch circuit that originates from the same enclosure where the branch circuit for the receptacle originates.
The requirement in 250.68(C)(1) does not permit this separate EGC to be connected to the metal water piping of a building or structure beyond the first 5 feet of where the piping enters the building or structure unless the conditions of the exception to 250.68(C)(1) can be met.
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.
There was a proposal in 2008 to allow the use of GFCI protection rule for ungrounded receptacle replacement for circuit extensions. This proposal was rejected.
18-16 Log #1396 NEC-P18 Final Action: Reject
George Stolz, II, Pierce, CO
Add new text to read:
(D) Replacement. Replacement of receptacles shall comply with 406.3(D)(1), (2), and (3) as applicable. Receptacles installed to additions to existing branch circuits shall be considered replacements for the purpose of this section.
The section in question (406.3(D)) effectively bends the standard requirements for new installations to provide relief for the installer when dealing with old work. Given the leniency put forth by this section regarding replacement receptacles, it appears that old 2-wire installations, while regrettable, do not present an imminent danger to occupants as stated in 80.5(B).
80.5(C) expresses that Additions...shall not cause a building to become unsafe.... By expressing explicit guidelines for additions to existing circuits, installers will be forbidden to connect an unbonded EGC between receptacles, decreasing the shock hazard in the event of an unbonded fault. In many cases, these existing circuits are extended to add receptacles to conform with 210.52.
The elimination of extension cord use should carry nearly as much importance as EGCs in this environment.
Panel Meeting Action: Reject
Section 406.3(D) addresses the installation of replacement receptacles. This proposal addresses the installation of new receptacles. Therefore, this text does not apply to this section. The panel rejects the concept of adding new receptacles to an existing two-wire circuit and applying the provisions for replacement receptacles rules. Replacement receptacles rules are to increase the safety of older two-wire branch circuits where a replacement receptacle is desired. Section 406.3(D)(3) does not address the extension of existing two-wire circuits. The applicable rules for extending two-wire branch circuits are contained in Section 250.130(C) and require the extension to provide an equipment grounding conductor. The references to Sections 80.5(B) and 80.5(C) are now contained in Annex G of the 2005 NEC as 80.9(B) and (C). Annex G is not enforceable unless specifically adopted by local ordinance.
Number Eligible to Vote: 12
So here is the code for the grounding conductor requirement-
Same in both 2014 and 2017 NEC-
250.130 Equipment Grounding Conductor Connections
(C) Nongrounding Receptacle Replacement or Branch Circuit Extensions.
The equipment grounding conductor of a grounding-type receptacle or a branch-circuit extension shall be permitted to be connected to any of the following:
(1)Any accessible point on the grounding electrode system as described in 250.50
(2)Any accessible point on the grounding electrode conductor
(3)The equipment grounding terminal bar within the enclosure where the branch circuit for the receptacle or branch circuit originates
(4)An equipment grounding conductor that is part of another branch circuit that originates from the enclosure where the branch circuit for the receptacle or branch circuit originates
(5)For grounded systems, the grounded service conductor within the service equipment enclosure
(6)For ungrounded systems, the grounding terminal bar within the service equipment enclosure
So, in conclusion, you must provide an equipment grounding conductor for any branch circuit extension and additional receptacles.
And sometimes you can get very lucky and find a grounding conductor in the box .
“Intelligence is the ability to adapt to change.”
If you find any errors or have additional information that would expand on any code, building standards or manufacturer requirements please let me know.
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