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This post mentions that it is now legal to add a separate wire to ground an outlet. What is the proper way to do this? Does the wire need to follow the same path as the ungrounded 2 wire path? How would the ground enter the junction box? How is it secured?

Is it legal to install 3 prong outlet without ground in the State of Georgia?

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What is the proper way to do this?

From the 2017 National Electrical Code:

(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

Does the wire need to follow the same path as the ungrounded 2 wire path?

No, it isn't required but if it did that would be preferable.

How would the ground enter the junction box?

It could be fished into another opening with a cable clamp.

How is it secured?

To the grounding-type-receptacle's ground lug and to the box, if it is metal, by means of a 10-32 ground screw.

There are many ways to accomplish this. These are the preferred methods of the trade but there are other acceptable ways.

Good luck!

  • So I would use a same gauge wire with green insulation and if I have junction box nearby with a ground on a different circuit that is ok to use? Does it need to be stapled before box entry or can I zip tie to another cable? – user1594257 Mar 1 '18 at 20:41
  • @user yes, nearby box will do if its ground wire is big enough (>= the size of the ground wire you must use) and it is served out of the same panel. You need to use the same wiring methods you'd use for any other wire or cable. You don't need green insulation, bare will do. As far as zip-tying it to another electrical cable, ask a separate question as that is a "complicated maybe". – Harper Mar 2 '18 at 17:47
  • I’m surprised @Harper didn’t add his usual advice which is this: if you anticipate needing to add a ground wire elsewhere plan ahead in how you route this ground wire. You might put in one or more junction boxes (or route it through existing boxes) so you have a convenient way to tap into this ground for other circuits that could use it. This will require some additional length of grounding wire and one or more wire nuts. – Stanwood Mar 3 '18 at 11:36
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The only legal way to install a 3 wire outlet without a ground is to feed it from a GFCI. As far as adding a ground wire you can tap another ground wire on any circuit that returns to the same service panel. Code only says the new wire can be run but not the path that it needs to take. If there is a grounded circuit close that is fed from the same panel use that it will save on wire and climbing around.

  • Can the ground be a green THHN wire of same gauge as the circuit? Are there different rules for routing of the ground wire since it's not energized? Does it have to be protected the same way as a THHN wire or can it be stapled right to a joist? Does it have to pass through joists or can it go under them? – user1594257 Mar 2 '18 at 2:56
  • Can it be a green thhn yes but why pay for insulation ? thhn needs To be in conduit. The same rules are true or apply for a grounding conductor as for other wiring 1-1/4 from the face of the stud. Splice accessible/ in approved / listed boxes and secured by staples or through bored holes. Last since the largest grounding conductor required is #4 for ufer and #6 for all other methods it may be possible to reduce the wire size. – Ed Beal Mar 2 '18 at 5:20
  • So what kind of wire would you suggest using that does not require conduit? What kind of wire can I use that has similar rules to Romex? Use Romex and only use 1 wire? – user1594257 Mar 2 '18 at 14:08
  • I would use bare copper, it would be the cheapest. – Ed Beal Mar 2 '18 at 14:22
  • My circuit is 12 gauge wire. I would be looking for #12 solid bare wire? Or do they make #12 bare stranded? If the other box is grounded can it just attach to outside of metal box or does it go inside and pigtail with other ground? – user1594257 Mar 2 '18 at 16:34
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I found a nice overview here:

https://www.jadelearning.com/jadelearning/thejunctionbox/replacing-two-wire-receptacles/

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