# Rewiring and extending a circuit, but leaving an old branch



## csab_

Hello,

I have a 1955 house with some old and some newer circuits. I'd like to rewire one of them, because the particular one doesn't have ground, and I need an extra receptacle with grounding.

Now here is the problem: the furnace room lights are on this circuit: they're branched off at box. I want to leave that part of the circuit alone, mostly because it would be very difficult to rewire it without disturbing some asbestos tape. But the branch is not grounded, and has some (currently) illegal exposed wiring in the furnace room (stapled to the bottom of joist while running perpendicular to them), so it's certainly not up to code. But it may have been when it was built - for all I know that circuit may be 60 years old.

Is this allowed? All the new work would be up to code, but I would leave that branch as it is. It's just two lights. We are on NEC 2014 and AFAIK there are no local rules. I tried to talk to the city inspector, but I just got his voice mail and he didn't return my call.

Thanks in advance,


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## Stubbie

You can extend ungrounded circuits if the extension and receptacle meet these requirements

* (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) For grounded systems, the grounded service conductor​ within the service equipment enclosure​ (5) For ungrounded systems, the grounding terminal bar​ within the service equipment enclosure​ Informational Note: See 406.4(D) for the use of a groundfault​ circuit-interrupting type of receptacle.


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## AllanJ

deleted all;gsfgsfdh,mvcm


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## AllanJ

The remains of an old (ungrounded) branch circuit may be tied into a new branch circuit after its portion continuing upstream to the panel had been decommissioned.

An old branch circuit may be upgraded piecemeal in any sequence, but 3 prong receptacles may not be substituted beyond where new up to date upstream wiring from the panel reaches except according to the paragraphs of code above.

No extensions may be made to the remains of an old ungrounded portion even if ground fault circuit interrupter protection or retrofitted separately run equipment grounding conductors were installed.

The presence of a wired-in old subcircuit on an otherwise new or upgraded branch circuit does not impose additional restrictions on construction of or additions to the new wiring except as pertaining to overall expected load on the entire circuit.


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## Stubbie

Allowed installation by the NEC, gfci is not allowed last I read the code to extend the circuit. It is allowed for existing circuits but not extensions to the best of my knowledge.


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## csab_

Thanks! You guys don't disagree. Stubbie explained how it is possible to replace a receptacle on an ungrounded circuit with a grounded one. You agree that the ungrounded piece may not be extended. And AllanJ gave me the positive answer I was looking for!

To make it more clear: (1) the circuit goes from the panel to a box (2) from that box to the lights (3) from the same box to some receptacles.

I will replace (1) and (3) with grounded NM cable, bring it up to code, and install an additional grounded receptacle on piece (3). I will leave (2) alone, and I will not extend that part either.


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