14

I just bought a 1955 house with 95% of the outlets 2 prong ungrounded. There seems to be one grounded 3 prong outlet in each room.

I reached out to my electrician for a quote to add grounds to all outlets in the house. He said I could do that or it would be cheaper to just replace the outlets with GFCI.

I can easily change out outlets for GFCI's myself. But I have 4 and 7 year old kids. What would be the safest or recommended action to take? Have an ungrounded GFCI or grounded regular 3 prong outlets?

9
  • 8
    @Ruskes This is completely wrong. Code specifically allows 2-prong outlets without ground to be replaced with GFCI outlets. In fact, a GFCI can be safer than a grounded 3-prong outlet.
    – DoxyLover
    Jun 13 at 0:43
  • 12
    Just for fun, you might check and see if those 3 prong outlets are actually grounded. Sometimes they are; you’ll find a bootleg ground; sometimes there’s no ground. Jun 13 at 0:57
  • 7
    @DoxyLover you are correct, I was wrong.
    – knowitall
    Jun 13 at 0:59
  • 6
    Minor fyi: old houses often have small junction boxes that don’t have room for gfci receptacles. One can change boxes, but there might be a lot of work involved. At that point, a gfci breaker swap starts to look cost effective. Jun 13 at 0:59
  • 5
    "95% of the outlets 2 prong ungrounded. There seems to be one grounded 3 prong outlet in each room." So according to basic math, each room has 20 outlets in total, 19 2 prong and one 3 prong. That's a lot of outlets.
    – Nobody
    Jun 14 at 13:54

5 Answers 5

21

The National Electrical Code specifically allows ungrounded 2-prong outlets to be replaced with GFCI outlets or 3-prong outlets protected by upstream GFCI outlets or breakers.

This can actually be safer than a properly grounded 3-prong non-GFCI. For example, if a child pushes a butter knife into the hot prong of a normal outlet, they can be shocked, while a GFCI will prevent any shock. A GFCI functions by comparing the current flow between the hot and the neutral wires. If the difference is more than a few milliamperes, it is assumed the the difference is leaking to ground, maybe through a person, and the GFCI trips.

Obviously, grounded and GFCI is best but GFCI alone is still good.

The only special requirements is that the GFCI outlet be marked “Not grounded” and any downstream outlet be marked “Not grounded, GFCI protected”.

BTW, for a downstream outlet to be protected, it must be powered from the LOAD terminals of the GFCI.

10
  • 4
    Fully agree 6ma (milliamperes) is the imbalance that will trip a U.S. GFCI it is a little bite less than my electric fence feels like anyway. GFCI is safer than grounding alone.
    – Ed Beal
    Jun 13 at 1:33
  • Good info thanks. So I would not need to replace every outlet in the room with a GFCI, just the one downstream and then the existing 2 prong in that room will also be covered?
    – richie894
    Jun 13 at 2:04
  • 1
    @richie894 Hopefully you meant the outlet UPSTREAM from the others, which is the correct method. The first outlet in the circuit would be the GFCI outlet and downstream outlets would be protected if connected to the load side if the GFCI outlet. Like others here said, code requires a label saying something like GFCI protected, no equipment ground. BTW, in a way, and others might snip me for this, but GFCI almost renders grounding obsolete for GFCI protected circuits. It's probably sacrilege for me to say that, but here goes! Jun 13 at 5:07
  • I am sorry but something is not clear to me. If you have a three prong outlet, I would expect the GFCI device to be somewhere upstream of the outlet, otherwise what purpose is ground serving? Can you really have a three prong outlet without GFCI? Jun 13 at 12:05
  • 9
    @VladimirCravero "GFCI" and the 3rd ground pin an an outlet are entirely unrelated. A GFCI detects an imbalance in the hot & neutral current and shuts off the supply, while the Ground pin provides a return path for fault current to flow should something like the enclosure of an appliance accidentally become 'hot' - leading to the 'regular' circuit breaker tripping due to the large fault current (orders of magnitude more than the GFCI trip current). You can have both, but they're not linked together.
    – brhans
    Jun 13 at 12:48
9

I also have a 1950s house with (until recently) most receptacles ungrounded. However, you may be pleasantly surprised, as I have been, to find good grounds available, despite currently having ungrounded receptacles. To summarize a little of everything, and add a few more things:

  • Ungrounded (2 prong) receptacles can often be replaced with grounded receptacles if there is a good ground (ground wire or, less frequently, metal conduit). This provides the default level of protection for most rooms except bathrooms, kitchens, laundry room, unfinished basement, garage
  • GFCI receptacles or GFCI breakers plus 3-prong receptacles can be used to provide equivalent protection to grounded receptacles if ground is not available. This is actually superior protection in certain respects, but does come at a cost as GFCI receptacles are more expensive than regular receptacles and GFCI breakers generally more expensive than GFCI receptacles. If you have an older panel then GFCI breakers may not even be an option.
  • Any 3-prong receptacles protected by GFCI that do not have an actual ground must be labeled "GFCI protected, no ground" (or similar language.
  • Tamper Resistant receptacles are required in most areas now and are definitely a good idea with little kids.
  • What you must not do is to bootleg ground to neutral. That will fool a 3-light tester but not provide any safety, and in fact be less safe that a 2-prong receptacle because it would give a false sense of security.
  • GFCI instead of ground provides life-safety protection but does not help with surge protection and other uses of the ground wire.
  • For bathrooms and kitchens (any location within 6 feet of a sink, tub or shower), always install GFCI, whether or not you have a ground wire available.
  • Properly installed, GFCI only needs to be on the first receptacle in a circuit and all later receptacles are protected. Doing this right is not rocket science, but requires a bit of thinking instead of mechanically replacing everything.
  • Old receptacle boxes may not be large enough for GFCI receptacles, and may not even be large enough for quality modern plain receptacles. Replacing boxes is easy in unfinished walls. In finished walls it gets more complicated, but not impossible, at least most of the time. There are rules for box fill, but the bottom line is that if you find it hard to fit new stuff in an old box, the old box is likely too small.
7
  • 1
    @richie894 Electrical box "extenders" are rings mounted to the front of an electrical box and provide additional depth/volume to the box. That may provide enough space to install a GFCI outlet without having to tear open the wall, but you'll have to decide if the aesthetics are OK for you.
    – Armand
    Jun 13 at 7:34
  • 1
    Even relatively expensive GFCI breakers might seem cheap, compared to the cost of pulling new 3-wire romex through (and patching) walls.
    – spuck
    Jun 13 at 22:49
  • @spuck Correct. But if OP's house is anything like mine (and we know it is at least a little like mine), the panel may be in no shape to accept GFCI breakers. Jun 13 at 22:51
  • @manassehkatz-Moving2Codidact, Updating the panel may still be the "less work/money" option compared to pulling wire. Guess it depends on how many outlets/rooms the OP is talking about.
    – spuck
    Jun 13 at 22:54
  • 1
    @EricDuminil no Jun 15 at 12:20
4

You should take look at the Temper Resistant GFCI, for added on protection.

They have mechanical device inside (Shutters) preventing "objects" from been inserted.

shutter

However, when the 2 gang up they can destroy anything :P

2
  • 1
    Technically required by code in most areas now. Annoying for adults. But a big deterrent for little kids, which is the goal. When I had little kids the temper resistant receptacles weren't really a common thing and it was all annoying plug in plastic placeholders except one different type of tamper resistant that I still have in one place in my kitchen. In any case, good idea if you've got little kids running around. Jun 13 at 1:33
  • 3
    @manassehkatz-Moving2Codidact The TR receptacles have gotten better. The current TR GFCI outlets I've been putting in aren't annoying.
    – Armand
    Jun 13 at 7:39
2

Don't make it harder than it is

Except maybe a little harder.

I'm sure 10 times a day electricians have a conversation like "Well, you could just install GFCI receptacles" and the customer decides "Well I don't need an electrician for that".

And you can guess where this goes wrong. GFCIs aren't quite as simple as that.

Now, the key point to GFCI is that GFCI is not a receptacle. It is a zone of protection which protects any number of outlets or loads.

GFCIs come in many form-factors: GFCI+breaker, GFCI+switch, GFCI "just a GFCI" and of course the receptacle with which you are familiar.

Yes, obviously a GFCI receptacle protects its own sockets. But all GFCIs can protect, really, an entire circuit. Heck, in Europe, one GFCI protects the entire house - although that has some, um, compromises.

This is done via terminals that every GFCI has, called "LOAD". If a load or several loads or outlets has its hot and neutral wire attached to the "Load" terminals of the GFCI device, then they will be protected by that GFCI.

That is the only thing "Load" should be used for.

Of course the novice who is smarter than the electrician watches a Youtube video or two and is putting a GFCI at every receptacle, and using the "Load" terminals anywhere there are 4 wires. And then a ground fault trips them all, and they never figure out how to get them all reset!

So, the trick is to use one GFCI to protect the whole circuit.

Easy mode is to use GFCI breakers if your service panel has modern breakers available. These are more costly than receptacles, though.

The second option is to carefully map every circuit (via trial and error disconnections). Locate the first receptacle past the service panel, and put the GFCI there.

Either case requires identifying all the receptacles on that circuit and marking the receptacles (as relevant):

 GFCI Protected
 No Equipment Ground
 Reset west wall this room

(the last line is purely optional). Making your own labels is legal so long as they are not handwritten.

And you are free to convert them to 3-prong outlets, even though they don't have a ground. Plain 3-prong outlets will suffice, but they probably need to be Tamper Resistant.

Or, grounds can be retrofit

But grounding protection is not as good as GFCI protection for humans.

Retrofitting grounds is allowed under certain fairly generous rules, and is handy when you have electronic equipment that needs grounding to suppress static electricity to reduce ESD damage.

Don't forget AFCI

AFCI is Arc Fault protection. It is designed to detect failing wire connections that are likely to start a fire. It "listens" electronically for the "sound" (waveform) of wire arcing. That can be just the thing for a house with old and suspect wiring, particularly if the wiring is aluminum.

(Other measures can help greatly with aluminum wire; I feel those + AFCI breakers make aluminum perfectly reliable).

AFCIs also can help with a child sticking 2 things in the hot and neutral slots, which a GFCI cannot detect if someone is being shocked between hot and neutral (the GFCI thinks that's just a normal load, but the AFCI notices the current curve isn't normal).

-2

The US National Electrical Code allows GFCIs to be fitted with missing grounds in retrofits, but NOT in new installations.

What that says to me is that the people writing the code thought that GFCIs with missing grounds were a "lesser evil" than the realistic alternative of people using cheater plugs or cutting off ground pins but that they did not consider GFCIs a proper replacement for grounding overall.

Proper grounding and breakers should disconnect the fault as soon as it occurs, a GFCI with a missing ground cannot do anything until after the shock starts.

Also, grounds aside if the house was wired in 1955 and hasn't been rewired since I would be very worried about the condition of the wiring. Afaict 1955 was before PVC became common and old rubber often degrades over those kinds of timescales.

5
  • 3
    The GFCI vs. grounding is a bit more complicated than that. From a pure life-safety standpoint, GFCI can actually be better than grounding alone. But there are other aspects (e.g., surges, noise, etc.) that GFCI does not resolve. When functioning properly, GFCI actually reacts much faster than a regular breaker to anything except a "dead short". Jun 13 at 2:48
  • 2
    You seem to be confused. “Proper grounding and breakers” are not a substitute for GFCI in any way. Not every fault is a dead short to ground. If a person manages to touch hot and ground, a 15A breaker (best case) is not going to save their life! A 6ma GFCI will.
    – nobody
    Jun 13 at 2:51
  • 4
    Case in point, I had a fault in my hot tub heater. Corrosion developed on the power terminals and electrified the shell of he heater, electrifying the water. The leakage was nowhere near enough to trip the 50A breaker supplying the hot tub, but it tripped the GFCI immediately.
    – nobody
    Jun 13 at 2:54
  • 1
    I've heard a quick and dirty summary that breakers are to protect equipment, and GFCI is to protect people. Jun 13 at 21:39
  • 1
    @MichaelRichardson: Breakers are primarily to prevent fires, which could endanger both equipment and people. A GFCI without an equipment ground will protect people, but may fail to protect equipment from some ground fault scenarios.
    – supercat
    Jun 14 at 21:57

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.