2-pronged to 3-pronged electrical outlets

Factual Questions
1

Hi. I know this has been done before (I’ve read Chicago Faucet’s threads here and here) and a few older ones. I don’t have the luxury of breaking down walls. I have a box of 20 three pronged outlets here, and my house is about 3/4 wired with two-conductor Romex with two pronged outlets. What is the easiest option for converting the two pronged outlets to three pronged ones? Of course, I asked the guy at Home Despot, and he said just hook up the two prongs and leave the third one dangling in the wind. I understandably don’t trust him, but looking at one outlet in the kitchen, it is apparently wired exactly like that (it is actually a two-pronged outlet with a screw-on outlet cover with a six three prong outlet expansion). This predates our purchase of the house, and apparently passed inspection the last time around. The ones in the computer annex are standard three-conductor Romex so this is not true of the whole house.

I want this to be “to code” or at least be able to pass inspection because we don’t want to stay in this house forever. Is it OK to just go get some 12 gauge wire and drop them from outlet to outlet, following the Romex, then connecting each circuit to the breaker box ground? Or do I need to replace all of the Romex with 3 conductor wire? Do I need to necessarily follow the breaker circuits – that is, if I only want to convert 6 or 7 of the outlets, can I just wire a ground between all of these and back to the box? Is there some way that I can take advantage of the 3 conductor Romex already in the attic – can I hook my other grounds up to these outlets and be good with that?

Thanks for the help. If it proves too complicated, I’ll leave the old outlets in place or phone an electrician friend. Since I have dropped CAT-5 and speaker wire all over the house, though, I suspected this might be something I could do myself. Something tells me that it is going to be a problem, though.

2

Assuming you really have two conductor Romex (sometimes you find that the cable actually has a bare ground wire in it that just isn’t connected) you can run an independent ground. As long as you have the outlets grounded back to a good quality ground, there is no reason they have to run along with the other wiring. Once you have a feel for the construction of the house, running a single ground wire is usually not that difficult. It does not have to be an insulated wire.

3

IANA electrician, but the best approach would be to run a single conductor ground wire to each outlet as suggested by KenGr. Each wire should go back to the bus bar in the breaker box, but daisy-chaining between outlets is O.K.

While running a ground wire to each outlet is certainly the best approach, most people don’t do it because it’s a pain in the ass. An alternative is to install GFCI outlets. With six or seven GFCI’s strategically located throughout the house, most (or all) of your outlets would be protected. You would then be allowed to install 3-prong outlets in the absence of a ground wire, provided each outlet is correctly labeled.

4

You were right not to trust him. That’s a blatent code violation.

5

Spoke to a few handyman/electrician friends tonight. A few problems, and I would like to know if anyone has run in to them or has an easy solution.

The first is that of logistics. It is all well dropping 3 conductor Romex instead of the 2 conductor stuff that is in there right now. With drywall, though, this apparently means that I would have to first drill a hole above the metal plug bracket, pull the new wire down (not an easy task if the old 2 conductor Romex is nailed to the stud), take the old stuff out of the bracket (removing the clamp holding it into the bracket), and wire it. Then, patch up the drywall, mud, texture, prime, paint. This seems like an awful amount of work for one silly wire. Any shortcuts? My electrician friend quoted me $25 an outlet to do this, so I’m thinking that there probably isn’t. He said that if he fixed one outlet, an inspector may demand that all outlets are fixed, so it would be best to leave everything alone. This sounds like BS to me – our inspector had no problem with only a few outlets being 3 prong – but he does this for a living.

The second is a follow up on Crafter_Man’s GFCI suggestion. I know our inspector complained because we don’t have GFCI in the kitchen and bathrooms, and he wanted them there. The previous owners gave us a few hundred dollar allowance or something upon sale of the house, but we never pursued it. So, if I do the GFCI thing without touching the 2 conductor Romex, I’ll fix those problems. So, is there a reasonable reference that can tell a relative newbie handyman how to do this? Namely, how do I hook up the GFCI, how do I hook up the 2 conductor Romex to 3 prong outlets downstream of it, etc. Or is it back to my electrician friend?

6

edwino: Installation instructions are included with each GFCI. They’re very straightforward.

One option is to simply replace all your receptacles with GFCI outlets. While this would certainly work, it would be wasteful and expensive.

When your house was originally wired, the electricians “daisy chained” many of the outlets like this:

Breaker box --> outlet A --> outlet B --> outlet C --> outlet D
Breaker box --> outlet E --> outlet F --> outlet G
Breaker box --> outlet H --> outlet I --> outlet J --> outlet K --> outlet L
Think of it as a two-wire bus system where each arrow consists of one “hot” wire and one “neutral” wire. The “hot” is usually a copper conductor w/ black insulation, while the neutral is usually a copper conductor w/ white insulation.

Note that outlets B, C, and D are “downstream” from outlet A; outlets F and G are “downstream” from outlet E; and outlets I, J, K, and L are “downstream” from outlet H. If outlets A, E, and H were replaced with GFCI outlets (and only these three), all the outlets would be protected.

On each GFCI you’ll see “line” connections and “load” connections:

The “line” connection for outlet A (which is a GFCI receptacle) should connect to the breaker box; the “load” connection for outlet A should connect to outlet B.

The “line” connection for outlet E (which is a GFCI receptacle) should connect to the breaker box; the “load” connection for outlet E should connect to outlet F.

The “line” connection for outlet H (which is a GFCI receptacle) should connect to the breaker box; the “load” connection for outlet H should connect to outlet I.

The only difficult task is determining which outlets are “closest” to the breaker box, and replace only these with GFCIs. In the above diagram, these would be outlets A, E, and H.

7

A few more things:

  1. The easiest solution is to replace your regular circuit breakers with GFCI breakers. But last I checked they were $50 a pop. Maybe they’ve gone down in price.

  2. My diagram is (obviously) a simplification; homes also have lighting circuits, outlets controlled by switches, etc. But as long as the circuits are isolated from each other you should be O.K. (If, for example, the neutral for outlet D is also connected to the neutral for outlet G, the GFCIs won’t function properly.)

  3. Test your GFCIs monthly, as they have tendency to get zapped after lightning storms. This is also why I do not like GFCI breakers; they’re expensive to replace!

  4. A Grounded GFCI does not need a label. An ungrounded GFCI must have the following label: “No Equipment Ground.” Regular outlets downstream from a grounded GFCI must have the following label: “GFCI protected.” Regular 3-prong outlets downstream from an ungrounded GFCI must have two labels: “GFCI protected” and “No Equipment Ground.”

  5. Most equipment with the third “ground” prong is grounded for safety reasons. And it is because of this reason that the NEC says you’re allowed to install ungrounded, 3-prong receptacles as long as they’re GFCI protected. But some equipment needs a ground for reasons other than (or in addition to) safety. A bunch of them are listed in this thread.

8

The above is why always, always, always have a competent electrician inspect the wiring in any home prior to purchase. The stories I’ve heard after talking with licensed guys would make your hair curl. Everyone wants to “save” money by DIY home-repair. Oftentimes it’s the work done inside the walls that’s not visible that is the most hazardous, too.

9

Consult with you local building inspectors. As a home owner you are entitled to do the work yourself…BUT if you do it, do it according to code(NEC).

GFI’s are required protection for Kitchens and toilet/bath rooms. Otherwise they are superfulous.

Run one of more # 10 bare copper ground wire from the main breaker box to the vicinity of each outlet which must be converted to NEMA std. 3-wire/prong. Connect from the #10 to the green/ground terminal with the same size wire as the original wiring (or a size smaller.) Connect to the #10 using split bolt connectors.

Bewqre of the Cog"

10

As others have already written, you don’t have to run romex with ground, you can just leave the old stuff in the walls and run a ground wire to each outlet.

The only problem is getting to each outlet. If your basement isn’t finished, or if the basement ceiling is removeable (panels, whatever), then you should be able to access the first floor walls from the bottom. If you can’t figure out where the walls are, use a small (say, 1/8") long drill bit, and drill a hole though the floor directly below the outlet. Go to the basment, and see where the drill bit is poking through. Now locate the cetner of the wall (probably 2" away from the little drill bit) and drill a larger hole (say, 1/2") from the Basement. Now you should be able to feed the ground wire through the outlet box, into the hole, then to the panel. If you need to, remove the old outlet box (sawzall with metal-cutting blade will make short work of it) and replace with a old-work box (I like Carlon Super Blue).

2nd floor is harder. You can work from the attic. It is easier because you can usually see the tops of partition walls, so you don’t have to drill from the other side to locate things. However, it is harder because you have to fish a ground wire through 7 feet of wall, which might have some blocking in it. It is still possible to do, though you are more likely to have to pull out the old outlet boxes. A long drill bit (6 foot log, flexible) can be really useful if you hit blocking halfway down the wall.

When doing an outlet, check on the other side of the wall to see if there is another outlet back-to-back. You see a lot of this with old wiring. If you see this you are in luck - that’ll be an easy run.
Make sure your panel is grounded.

11

Basement? What’s a basement? I live in a place with a water table that is like 2 feet below street level. Integral parts of home inspection are mold testing and checking to see if the foundation is cracked or even failed. Neither are particularly unusual and neither are particularly going to kill a home sale. I understand this is not the way it works if you don’t live in a swamp.

If I am going to drop an extra wire, what I probably will have to do is drop the ground wire with the Romex from the attic in between the wall. I will have to drill a 1 inch or so hole about the outlet, then fish the ground wire out. Then I will have to somehow get it into the outlet box, probably by drilling a hole in the outlet box. Then wire, then patch the drywall, then texture, prime, and paint. I don’t particularly want to do this, especially since we just patched and painted most of our walls.

You will all be glad to know that for the newly remodeled room (the John D. and Catherine T. MacArthur Guest Estate), I chickened out and just replaced the old ivory 2 pronged jacks with new white 2 pronged jacks. So Dun Edwino won’t be burning down due to shoddy wiring any time soon. For the rest of the house, I have left a message for electrician friend (he’s hard to get in touch with, which is why I came here) to see if the GFCI way works in our region (Are there city- or state-specific ordinances or modifications to the NEC?) If it is all good, I’ll have him help me out with those or at least inspect my work when I am done.

Thank you all for the awesome answers.

12

Assuming the electrical boxes are mounted in the usual way, there’s just two nails holding the box to the stud. Using a screwdriver, pry the box a little bit (1/16" or so) away from the stud, slide in an appropriate saw, and cut off those two nails. Pull out the box. You now have a 2" by 3" hole to fish through, and no wall repair is needed (unless you are sloppy with the saw). Plastic old-work boxes should fit right into the hole (although you’ll probably need to enlarge the hole in the wall a bit).

Appropriate saw is a sawzall with a metal-cutting blade. Alternatives are a handle that accepts sawzall blades (with a metal cutting blade attached, of course), or a “stubby” hancksaw handle with blade.

Given that the water table is so high, do you have a problem with flooding? If so, GFCI everywhere isn’t a bad idea.

13

Yeah we have a problem with flooding. My street is flood-prone, but my house has been spared the previous two floods, including a flood in June 2001 that just about flooded the whole damn city. It is a good point though. We had a heavy spot of rain a few months ago which brought the bayor two streets away out of its banks. We had three feet of water in our street, but luckily none in our house (although we saw the telltale roll of carpet and padding on a few of our neighbor’s curbs the next day…)