I’ve read that as an alternate to re-wiring your entire house to get more protection (and a 3-prong adapter) at your outlets, you can safely (and under code) just replace each outlet with a GFCI outlet (or a central GFCI, I suppose). It seems to me that’s cheating - is it? What level of safety does it provide using a GFCI on an ungrounded circuit versus a grounded circuit?
A GFCI and a grounded outlet do two different things and protect against two different scenarios, and one is not a replacement for the other. A grounded outlet protects against a short in the WIRING, specifically, a wire coming loose and contacting a metal electrical box or housing. If the box or housing is grounded, the fuse or breaker will blow and presumably you’ll realize you have a problem. If this DIDN’T occur, anyone who touched the box or housing would get a shock - whether you’ve got a GFCI outlet is irrelevant. A GFCI outlet protects against a short (or more commonly a current leakage) involving YOU and an electrical device plugged into the outlet. If an appreciable amount of current flows from the appliance through you to an earth ground (presumably because your hands are wet - typically GFCI outlets are installed near sinks), the outlet trips. So, in the first scenario, the problem usually is a frayed or broken wire, whereas in the second, the problem is carelessness on your part, because you didn’t dry your hands.
As far as buildings codes in the US go, the only acceptable way to replace a two-prong outlet with a three-prong outlet in an ungrounded circuit is a GFCI outlet. I wouldn’t use them for every outlet if the entire house is ungrounded, though.
In my mid-century, where some outlets are grounded and others not, I replaced the old two-prong outlets with GFCI outlets. It’s expensive, but it meets code. The tricky part is determining the polarity of the wires; color codes in the good 'ol days were much different than today, and the decades of dirt and nicotine that soaked into fabric insulation can make both wires look black. When you disconnect the old outlet, make sure you have a close look at the old outlet, and note what wire is hot. One advantage of a GFCI; if you reverse the wiring, the outlet won’t work, period.
In Canada, it’s acceptable to replace an ungrounded two-prong outlet with a three-prong outlet that had the ground hole plugged. This allows the use of Decora outlets and cover plates in ungrounded circuits. It’s not kosher in the US, though; if you have ungrounded outlets and want to go Decora, GFCI is the only way.
So in other words, if I don’t want to tear apart every wall in my house to re-wire every outlet, I can at least install GFCIs and get some additional protection against some faults, and meet code. Sounds decent to me for some outlets. And they’re not that expensive any more, about $10 an outlet or something, right?
That’s correct, although if you’ve got an ungrounded house, I’d look at rewiring if you plan on staying there.
GFCI outlets now cost about $12 to $15. Cheaper GFCI outlets may have passed UL tests, but reliability in the long run could be questionable. I prefer Leviton (usually made in the USA or Mexico) to Cooper or other manufacturers that outsource to China. GFCIs can go bad, so test them often.
EDIT: I don’t think you have aluminum wiring in your house. If you’ve got ungrounded outlets, it tells me that they date to the 1950s and earlier, before aluminum was used in the late 1960s. Never, ever connect aluminum wiring to a modern switch or outlet; most are designed for copper wire only.
The house was built in 1960, and AFAIK has copper wire all throughout.
But in terms of grounding it, there’s just no cheap or easy way to do that so it’s not going to happen. There are a couple of grounded outlets that the previous owner made by running wires to the plumbing, but I thought that was a code violation. Add to this the fact that I can’t even get an electrician to give me a quote… 
I can’t even say the people who built my house were cheaping out. Not only did they install all copper water and waste pipes, they used things like 28-foot 2x8’s (yes, single pieces 26 feet long) for joists.
You can replace non-grounded receptacles with GFCIs, but you do need to add a “No Equipment Ground” label to them. References to the NEC are in italics below. And note the exception to new work. This workaround only applies to existing wiring. As soon as you add anything, you have to rewire the circuit with a ground.
(From May NEC Questions)
I can see that my Thanksgiving holiday is going to be spent installing 30-40 GFCI outlets…fun for the whole family.
What kind of GFCI outlets are you using? I have a new one, purchased recently, still in the box. I tested it just now in the basement. It works fine either way - white to silver terminal, black to brass, or the other way around. Perhaps you’re talking about getting the LINE and LOAD terminals mixed up, which is a different matter.
I get uncomfortable when I hear talk like this. For one thing, you’re talking about a major project. Have you done anything like this before? Also, to repeat what I said earlier, a grounding outlet and a GFCI outlet do two different things. If you install a GFCI outlet in an ungrounded box, the socket for the third prong won’t be electrically connected to anything. I know the outlet will work and is allowed by code, but if you do the whole house this way your wiring will still be missing a major safety feature and whoever buys the place from you won’t realize it. If it were my house I’d limit the GFCIs to the places where they’re recommended, namely bathrooms, damp locations, etc.
BTW, I take it your house is wired with Romex with no bonding wire?
Just replacing outlets? Yes. Is there more to it than that? And it’s not so big a job as long as I do one outlet at a time and test each one as I go. I doubt I’ll do more than 12-15 in truth before I get tired of it.
Well, the house isn’t going to be re-wired completely, and the way I see it the GFCI is safer than what I have now. Right now I’m using 3->2 prong converters for all my appliances, the new way I have no converters and at least I have GFCI protection. Also, I will be putting the little sticker on that says “No Equipment Ground”. And I guess another thing is I have no intention of selling the house, but if I do, and forget to mention it, their home inspector can plug his little tool into the outlet (like I have) and see that there’s no ground.
That’s what it looks like, but I haven’t checked all outlets.
I’ll e-mail you.
This post is over ten years old but I’m posting an update for anyone reaching it via a web search. Some of the information provided previously is incorrect. A GFCI works by constantly sensing the current running though both the hot and neutral wires. If there is even the slightest difference between the two, the circuit is shut off immediately.
Therefore if any current is flowing from the hot wire to ground instead of back through the neutral wire the power will be instantly disconnected. That is why no ground wire is needed.
Also, it is usually NOT necessessary to replace EVERY ungrounded outlet with a CFGI outlet. Typically several outlets are on the same circuit. As long as the FIRST outlet in the chain that has its power coming directly from the circuit breaker is a GFCI, then the rest of the outlets on the circuit AFTER the GFCI outlet are also protected by it.
This is why is is critical that ALL of the following be identified correctly:
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Hot vs. Neutral wires
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Line vs. Load wires (The wire coming IN from the source or previous outlet in the chain is the LINE, and a wire going out to the next outlet is the LOAD)
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The FIRST outlet in a circuit must be determined, as that must be the one replaced with the GFCI outlet. The others can be replaced with regular three prong outlets (with no connection to the ground screw).
So use the money saved by not needing to replace every outlet with a GFCI and invest in a good meter or voltage detector. Turn the circuit breaker off and verify that every outlet you plan on replacing is unpowered. If not, then it is on a different circuit. Work on only one circuit at a time. Find ALL outlets on that circuit then disconnect ALL wires from each one (be sure the power is still off). If all wires on all outlets are not disconnected then there is the possiblity of power feeding back through the neutral and you will get misleading results (and possibily a shock from the neutral wire).
Make sure no wires are touching each other or anything else, and that all exposed wires are proected from childern, pets, etc. then have someone turn the power back on and find the ONE hot wire. This will be the HOT LINE for the FIRST outlet. Turn the power off again and connecte this wore to the HOT, LINE terminal. The corresponding wire will be the NEUTRAL LINE connection for that outlet. If there is another pair of wires at that outlet that go to the next outlet, connect these to the LOAD terminals, again observing which is hot and neutral.
Now the rest of the outlets on that brach circuit can be replaced with regular three prong oulets. There is no distinction between line and load on these, but be sure the hot wires (usually black) go to the darker of the screws (usually brass colored) and the neutral wires go to the lighter screws (usually silver coloered). If you look closely at an outlet you will see that one of the vertical slots is longer than the other. The hot is the shorter of the two.
In addition, as noted earlier, ALL outlets affected must be labelled properly. The GFCI needs to be marked “No Equipment Ground” and EACH of the downstream outlets marked "“GFCI Protected” and “No Equipment Ground”. Generally, the GFCI outlet comes with several stickers for this purpose.
Finally, I recommend that all outlets be oriented with the “ground” hole on top if installed vertically or with the neutral slot on top if mounted horizontally. Contrary to popular belief there is no requirement that these look like a “face”. Using the suggested method means that if a metallic object (for example a fork) were to fall on a plug that migh have worked loose a fraction of an inch, it will contact the “ground” prong (if preset) in the case of a vertical outlet or the neutral prong if a horizontal outlet.
I just found this site while searching Google for electrical issues. I am in Wisconsin, I know very little about codes. 4-5 yrs. ago, I had the house “re-wired”. The swiftness of the contractor was impressive, he really looked like he knew what he was doing. I didn’t think it was necessary to check his work.
(The fuse box, which contained 8 circuits, was replaced with a 200 amp breaker box with 18 circuits.), as well as a 60 amp sub-panel in the garage.
There were some outlets in place already with a three prong recepticle,without the ground port connected to anything. It was the same after he left.
There was an exterior outlet that he said he re-wired that wasn’t grounded after he left. I found out about that much later, after my wife got shocked by it.
I know how to read those little golfball sized testers which told me the outlet was reverse polarity and open ground. I fixed that one.
Yesterday I got shocked by the light switch in the bathroom, (no wet hands) which has a GFCI outlet right next to it. One outlet has 60 volts when the breaker is off. The one behind the refrigerator, I specifically told him to run a new circuit to because sometimes it works and sometimes it doesn’t. It worked for quite awhile after he left but it went out again. I checked the voltage with the breaker closed, i.e. in service, and my meter said it had 97 volts.
I don’t know if it’s been too long to go after him or not. I’m on disability and the wiring was done with a government re-hab loan.
Any thoughts?
get an electrician, different from the one who did the wiring, out to look at your situation.
don’t use receptacles or switches that have given you shocks.
don’t try to fix things yourself, even if you don’t die in the process you could create a hazard that would produce shock or fire later. it takes skill to sort out incorrect or poor previous work or deteriorating wiring.
I am not sure how old the post is at this point… But THANK YOU so very much for correcting the misinformation, I was just randomly reading through some of the “web” and saw this, the information that was being given was.. mmmm partially true. At any rate thanks for clearing this up, I was going to do the same thing you did!!
–Ele
As I gathered the green wires I’d run to replacement 3 hole duplexes
and tightened the split-bolt to connect them to the white-wire bus
in the fuse box I wondered:
Why isn’t it appropriate to connect the Equipment Ground screw of a
duplex to the Neutral [white] wire when a separate ground is not
available as is the case in our 1950 vintage house ?
Would it defeat the GFCI detection ?
If so, would it be appropriate on a non-GFCI protected duplex ?
How timely that someone resurrected this zombie. My wife and I are closing on a 1959 house next month, and I don’t think I saw a single 3-prong outlet throughout the house!
OMG where to start!?
First, if you do not know why, then you should not be in your fuse box at all. In fact, technically only a licensed electrician should remove the cover from your box.
That said, it is extremely dangerous to connect any ground wire to a the Neutral (white) wire at a receptacle or anywhere else. Simply, it would energize the ground as well as defeat any other safety that would be provided by having aground.
The neutral bus in your box is grounded so that in case of a short at the panel, it is grounded.
And yes, the GFCI will not work.
Hopefully, this message reaches you alive and well.
in a fuse/breaker box is a deadly hazard there are many places to come in contact with electricity and die. only an experienced and knowledgeable person (beyond a DIY person) should go in there. if you weren’t an immediate hazard to yourself you could create a hazard for anyone in the house later.
the grounding connection of anything does not carry any current except when something wrong is happening. do not connect it to anything but something grounded.
if a house has vintage wiring it might be a good idea to get an estimate on upgrading the electrical. if the total house is not upgraded then some new circuits could be added where higher current or grounding is needed.