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A contractor looked at our house and told me that you can't fix a house (with old wiring) that has some outlets that are not grounded. He said that you can go on YouTube and search the internet and it will tell you that you can. He says that the only way to properly fix and ground everything is to do a whole house rewire.

Is he correct?

If, theoretically, you have an old house that has no ground whatsoever, can you run a grounding wire from the panel to all of the outlets to fix this?

updated

We have BX/AC wiring. And also apparently we have "...old-style AC (BX) with cloth insulated wires in a paper overall wrap under the spiral armor (no bonding tape)" Courtesy of @ThreePhaseEel.

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    I think the contractor's point was probably that if you're running a single grounding wire to each box, you might as well just re-wire everything. Fishing 3 conductors isn't really much different than fishing one. – Comintern Sep 17 '16 at 4:41
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    It depends on what kind of old wiring you have -- K&T, old NM, BX/AC, and conduit all require different techniques to fix this. – ThreePhaseEel Sep 17 '16 at 12:15
  • Hi @ThreePhaseEel...we meet again...from this post diy.stackexchange.com/q/99366/672 people (including you) helped me determine that we have AC/BX. – milesmeow Sep 18 '16 at 3:31
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It's perfectly legal to run JUST a ground wire to retrofit old work. You do not need to also pull all the conductors. This is legal as of NEC 2014, so if your region hasn't adopted it yet, just wait.

People who say "might as well pull all new conductors" do not fully understand what the new rule permits. Retrofit grounds do not need to follow the same path as the conductors. What's more, you can borrow/share grounds from one circuit to another as long as they all terminate back at the same panel, and are of large enough size. That is much easier than pulling all new homeruns! For instance you can run a 10 AWG ground to a clothes dryer, and any nearby 20A outlet can simply ground to that, etc. etc.

It is also both legal and safe to put GFCI protection on ungrounded receptacles or circuits. GFCI protection is safer than a ground, although not as awesome for surge suppressors and radios.

  • Could the grounding wire that we run from the panel and for sharing be an uninsulated wire? What gauge wire should it be? – milesmeow Sep 18 '16 at 23:51
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    Bare wire is fine. It must be thick enough to be legal as a ground for the circuit it is protecting, or in the case of circuits sharing grounds, the largest circuit it is protecting. Rule of thumb, ground wire should be same size or larger as conductors, though I believe there are exceptions for 8 and 6 AWG conductors. I would use nothing smaller than 12AWG generally, the cost difference is negligible. – Harper Sep 19 '16 at 0:34
  • If I'm running this ground in my crawl space, can I use these waterproof wire nuts: amazon.com/King-Safety-62225-Waterproof-Connectors/dp/… to connect/share ground wires? – milesmeow Sep 19 '16 at 6:21
  • Can't speak to the code compilance of those, but the best place to get good product info is patronize your local electrical supply house, the one whose parking lot is full of electrician trucks at 7:30am. They deal with this stuff all day and can advise products. Home Depot and the big box stores are pretty worthless. – Harper Sep 21 '16 at 1:15
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You didn't state what you want. It appears that you want grounded outlets in some places that do not have grounds. If your house is very old you may have metallic tubes that contains the wires. If you open an ungrounded outlet and find a metal box with metal conduit connections, simply replace the outlet with a grounded outlet and connect the ground by a wire to the metal box.

Romex always has a ground wire. Before Romex wires had to be in a metallic tube. The metallic tubes are connected to a ground rod outside your house. You might want to look for the ground rod connection below the meter can outside your house.

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    Romex/NM without grounds was used in the 50s and probably the 60s as well -- I have a 50s era house wired almost entirely with NM and it has no grounding basically anywhere. – ThreePhaseEel Sep 18 '16 at 1:57
  • And before the 50s there was knob and tube which also didn't have a ground and was run in the stud space as 1 wire per stud. – bobpaul Jan 28 at 17:07
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He is not correct. You can fish new 3 conductor wires yourself by attaching them to the old 2 conductor wires and pulling from the electrical panel. Keep in mind, it won't be easy and in some cases you may have to open walls. You can buy tools for fishing wires, just look on amazon.

If you can get by with just a few outlets grounded, say for your computer and appliances, then you can install a GFI outlet in the remaining ones. That way, your home is safe.

Keep in mind, an ungrounded plug is both dangerous, and won't allow surge protectors to function correctly. So while you wait to figure it all out, make sure any expensive electronics (TV, computer, sound systems, etc) are unplugged when not in use to prevetn damage from surges.

  • So your saying that I can potentially rewire the whole house myself...add ground, add the appropriate wires and receptacles, etc.? – milesmeow Sep 18 '16 at 5:38
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    Just to clarify, I believe this answer is referring to pulling an entirely new cable assembly, correct? Fishing new wire through an old AC cable assembly's outer sheathing would technically not be legal because you would be reusing the outer sheathing of a manufactured cable assembly as though it were flexible metal conduit. The sheathing of AC in this case is most certainly not UL listed to be used as FMC if the listing can even be determined based on the age of the home. – statueuphemism Sep 18 '16 at 12:45
  • No I'm talking about about taping the new 3 conductor cable to the end of the 2 conductor wire and pulling the 2 conductor wire at the breaker box. If all goes well, you'll end up with a brand new 3 conductor wire that you can connect to the breaker box. If the breaker box has no grounding, have an electrician put it in. It's a lot less expensive than having him rewire all of your plugs. Also, there is very little you can do yourself when it comes to electricity in homes and still be "legal". This is no exception. – Matthew Goulart Sep 18 '16 at 14:20
  • If OP really has conductors in conduit this MAY work. Sounds like the conductors have that thick cloth covering and the conduit is spiral rather than smooth so I'd expect this to be quite challenging on longer runs. I'd try one of the shortest first to see how well it works. – topshot Sep 18 '16 at 17:25
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    @MatthewGoulart 'there is very little you can do yourself when it comes to electricity in homes and still be "legal".' Not true--I am rewiring my entire home myself with all applicable permits pulled from the city and inspections so that it is entirely legal. It can be tough to get permits to do electrical work yourself with regards to submitting plans or demonstrating knowledge of the NEC (depending on local requirements) but electrical is one trade you absolutely do not want to mess around with if you are not familiar with the legal (and safe) way to perform the work. – statueuphemism Sep 18 '16 at 17:48

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