Adding Outlets and Lights from ungrounded AC outlet

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Old 09-20-20, 01:24 PM
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Adding Outlets and Lights from ungrounded AC outlet

Hi,

I have an old 1938 house with just one electrical outlet in a bedroom that is supplied by only a 2-wire (original wire) line with no ground and no way to add a ground.

I wanted to add a number of outlets branching in two different directions from this original outlet and also add a couple of lights from this circuit to an attic room on the other side of the bedroom. My idea was to replace the original outlet with a GFCI outlet and then branch from it in two different directions.

I would route most of the new wire by notching into the studs behind the existing baseboard and then protecting the wire resting in the notches with protective nail covers.

Since there is no ground coming into the outlet, I don't think it makes any sense to connect the grounds of the new outlets to the ground on the GFCI outlet (or am I mistaken)? So, in the proposed diagram below, the grounds on all the outlets would not be connected. This is what I am proposing. Will it meet code?

Proposed Wiring Diagram to upgrade a single ungrounded outlet to a GFCI protected series of outlets and lights.
 
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Old 09-20-20, 01:41 PM
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Unfortunately ungrounded circuits should not be extended. Can you get a new cable and install a new grounded circuit?
 
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Old 09-20-20, 01:55 PM
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No, there is no easy way to add a new cable with a ground without doing some serious ripping up of a couple of walls (and the walls that would be involved have unique texture and/or beautiful tile work on them).
 
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Old 09-20-20, 04:24 PM
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The intent of the code is to encourage the stringing of new wire or cable and decommissioning of the old.

Surface wiring using Wiremold(tm) and similar products can be used.

A separate ground wire can be added after the fact from the existing ungrounded outlet down to the panel holding the breaker for the branch circuit, exactly, approximately, or vaguely following the route of the existing circuit conductors. Should the other end of this separate equipment grounding consuctor first reach a fat ground wire (grounding electrode conductor) going to a ground rod, to an approved water pipe grounding electrode, or an approved concrete re-bar electrode or (new) first reach an outlet box that is properly grounded, it may end and be attached there.
 
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Old 09-20-20, 06:05 PM
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No, there is no easy way to add a new cable with a ground without doing some serious ripping up of a couple of walls
You might think that but in many cases, there are ways to fish between multiple floors without opening the walls. One of the most common places to fish is along the main plumbing stack. I have fished from an attic, past two floors, into a basement along the main stack using #12 jack chain. Also, a house built in 1938 may have been balloon framed which makes fishing between floors a snap.
 
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Old 09-21-20, 03:36 AM
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Just for "giggles" are you sure there is no ground. Did you test the receptacle box with a meter to see if the box is in fact grounded. Old style was to wrap the ground wire out the clamp to the metal box. You may not be able to see this since it would be in the back of the box.

Also more than likely there are only a few circuits in the home. You want to add more receptacle and lights to that existing circuit you will be stretching it.
 
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Old 09-21-20, 04:43 AM
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<< Did you test the receptacle box ... >>

Getting continuity between the box and the house ground* does not prove that a good and sufficient equipment grounding path exists. For example BX or similar spiral flex conduit without a bare wire or strip running the full length within can show continuity if measured to determine grounding but it does not qualify.

<<... likely there are only a few ... >>

Again the hint is that new wiring should be strung for all of those new receptacles no more than 12 feet apart etc.

A separately run equipment grounding conductor can be hidden behind the baseboard or fished along with the other wiring you planned to add.

Simply extending an ungrounded circuit does not meet code.

A ground fault circuit interrupter, in addition to providing near perfect protection from accidental electrocution, makes it l code compliant to replace a broken receptacle in an ungrounded circuit when you cannot find a new 2 prong receptacle.

* House ground -- Aka grounding electrode system. The neutral bus bar in the panel with the first whole house disconnect (switch or breaker) together with grounding electrodes and interconnecting wiring.
 

Last edited by AllanJ; 09-21-20 at 05:02 AM.
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Old 09-21-20, 10:12 AM
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Thanks for all the feedback. I learned a lot here. I'm going to try and find away to bring in a grounded line through the attic and just use that line to feed all the outlets.
 
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