I'm preparing my mother's home for sale. It was built about 1953 and the
wiring lacks the usual third ground conductor. To make it possible to
conveniently plug in stoves, refrigerators, and power tools with
three-wire cords, my father simply replaced two-wire outlets with
three-wire ones, leaving their ground lugs disconnected.
At this point, every switch and outlet in the house is worn out,
paint-covered, or installed up-side-down, so I plan to replace all of
them. I started out intending to turn the clock back and replace all the
outlets with two-wire ones, but it appears that I can't even buy them
any more. Certainly the local HD doesn't have any.
So the question is whether there's a proper way to connect a three-wire
outlet to antiquated two-wire cable?
Your simplest option is to put a GFCI receptacle in every location. It may
not sound cheap but the alternative is replacing the 2 wire cable with 3
wire cable. Not really practical unless you are already doing a gut and
There should be a sticker that comes with the GFCI to alert users that the
plug is not really grounded. It does provide protection as it will trip if
any current flows into the ground tab.
That is pretty reasonable advice with one exception: Where the
3-wire is actually needed, such as for computers, stereos, etc..
Further: You don't need a GFCI at every location: You only need
one per circuit, placed in the right location, meaning the
receptacle which physically connects to the fuse/breaker box.
Then that receptacle and all those beyond on the same circuit are
You can also buy ckt brkrs with gfci functionality, along with
arc suppression and detection. IMO that would be the most
desired from a new buyer perspective. Don't be too surprised if
the lack of a third wire hurts some prospects, though.
If you're in doubt about anything, it's easy to just call your
local code enforcement office to get details: Every locations
adds its own laws and rules to the mix.
Use of a single GFCI or a GFCI breaker does not solve the problem of not
having a ground wire in the first place. If you use a GFCI receptacle and
connect several receptacles downsteam, you will get some GFCI protection but
not from current into ground (the ground tab on those will still be open).
Only at the GFCI receptacle itself do you get virtual safety ground
I think I understand you. But just to be sure, are you saying that even
without a ground wire connected to it the first GFCI receptacle would
trip if an appliance plugged into it equipped with a three wire cord and
plug developed internal leakage between hot and ground (or on the
fancier GFCIs also between neutral and ground.), but that you don't get
that level of protection on the downstream ones?
I'd assume you wouldn't get that protection on the first receptical
either if there was no ground wire connected to it. I can't see where a
leakage current to ground would flow if there was no ground wire for it
to flow through.
If what you said assumed there WAS a ground wire to connect to the GFCI
receptical then I agree with your statement, but that's prolly not what
the OP has, unless he's lucky and the wall boxes are grounded, perhaps
via the bare ground wire used in some of the old BX cables.
The ground fault device and anything plugged into any outlets connected to
the load side of it, will cause the GFCI to trip if any leak of current to
ground occurs, regardless if the outlets are grounded. The GFCI does not
need a ground connected to it to function
Of course, but that's NOT what I asked.
I was talking about (internal fault) leakage to the safety ground lead
(chassis) oF an appliance with a three wire cord and plug. And, that
faulty appliance is plugged into a GFCI outlet which does not have a
ground wire run to it. i.e. an outlet which would require the little
label stuck on it warning that there was no safety ground there.
Take a look at Sam Goldwasser's diagrams and explain please how the GFCI
can sense internal leakage to the safety ground lead of the appliance if
the ground pin hole in the outlet isn't connected to anything.
The GFCI will not immediately sense if there is a leak to chassis
ground in a faulty appliance. However, the instant a person touches the
live chassis and completes a path to ground, the GFCI will trip,
preventing injury. A live chassis by itself isn't dangerous - only when
someone touches the chassis and gets shocked is it a problem, and a
GFCI outlet will protect against this.
For the last time I'll say that I agree completely with all that. I
checked into this thread when I questioned this statement by PipeDown,
when he said:
Use of a single GFCI or a GFCI breaker does not solve the problem of not
having a ground wire in the first place. If you use a GFCI receptacle
and connect several receptacles downsteam, you will get some GFCI
protection but not from current into ground (the ground tab on those
will still be open). Only at the GFCI receptacle itself do you get
virtual safety ground protection.
If by "safety ground protection" PipeDown meant that the GFCI would trip
on an internal ground fault in an appliance I didn't believe it would
unless there was a ground lead connected to it.
As Goldwasser says:
GFCIs and safety ground:
Despite the fact that a Ground Fault Circuit Interrupter (GFCI) may be
installed in a 2 wire circuit, the GFCI does not create a safety ground.
In fact, shorting between the Hot and Ground holes in the GFCI outlet
will do absolutely nothing if the GFCI is not connected to a grounded
circuit (at least for the typical GFCI made by Leviton sold at hardware
stores and home centers). It will trip only if a fault occurs such that
current flows to a true ground. If the original circuit did not have a
safety ground, the third hole is not connected. What this means is that
an appliance with a 3 prong plug can develop a short between Hot and the
(supposedly) grounded case but the GFCI will not trip until someone
touches the case and an earth ground (e.g., water pipe, ground from some
other circuit, etc.) at the same time.
I'll say no more on the subject.
Have you checked to see if a ground wire is attached to the back of the
receptacle boxes? My house was built at the same time and I just added
a jumper wire to the existing ground and then to my new three pronged
receptacles. Fully grounded.
Ground tab is floating(=no ground) but in certain cases, if a device
plugged in has a leakage current it'll trip when person using it touches
the device housing(ground) after taking a jolt which could cause an
injury. Not a good adviuce from the safety point of view.
if its armored BX just add a pigtail between box and receptable ground
terminal while observing hot black side to brass screw cold white wire
to silver colored screw. please dont use those backstap receptables
they are cheap but junk quality
Also don't confuse the "pushwire" outlets which grab the inserted wire
with a crummy spring tab with the "backwire" outlets that clamp the wire
inserted in the hole when you tighten the screw. The "backwire" type are
just fine while the "pushwire" type are junk.
On Mon, 15 May 2006 19:03:15 GMT, "Richard M. Utter"
This is illegal, and life threatening, so you might want to fix that
Per the NEC you can find the first outlet, and wire that with a GFCI,
and have it feed the downstream outlets. So the first(the GFCI) and
the downstream receptacles are ground fault protected. Just be sure
the follow the rules, and mark each outlet with the normal "GFCI
protected" and "No Equipment Ground" stickers.
Side note, a local jurisidiction here in eastern Pa, will not allow
this. You either route a ground wire, or you use two prong outlets.
The idea is to not update the outlets, but to replace the wiring
method to include a equipment ground wire.
Check with your local codes, they usually are more stringent than the
I've seen them at our HD, but if I had to buy them in bulk, I would go
to an electrical suppy house.
As mentioned above, follow the codes, especially the requirement that
only qualified personal will work on electrical systems. :D
tom @ www.FreelancingProjects.com
I'm fairly sure that GFCI breakers have a limit to how many downstream
outlets you're supposed to be able to feed with them. (four, maybe?)
If I was going to live in the house, I'de replace all of them. Since
OP is preparing the house for sale, the cheapest option is probably
to replace the breaker(s). Anyone who cares is going to be unhappy
about the lack of ground-wire, using breakers instead of GFCIs isn't
going to make matters worse.
Another thing to check is whether you've got armored metal cable
that's grounded, in which case, pigtailing the receptical ground
to the box may be enough to satisfy the house "inspector"s little
LED tester. (Whether that's safe or code compliant in your area
is another question.) My second-floor circuts are like that.
I've not seen any that hint at such a thing in their instructions.
There's no reason I can think of where that would make any sort
of sense. They have to be rated for 20A passthru, otherwise,
you couldn't use them at all. The detection circuitry has no way
of knowing (or caring) about how many outlets are downstream of it.
If they somehow did have such a restriction, I suspect that
they'd fail UL/CSA approvals.
But who knows, perhaps some manufacturer does have that in their
instructions to try to trick you to buying more GFCIs than you need.
It _would_ make a certain amount of sense to limit the number of
outlets beyond each GFCI in order to minimize the number of outlets
going dead when one trips. That's a useability issue, not a safety
or operability one.
I'd test 'em, and if they tripped properly, leave 'em alone.
While the NEC does permit cable sheath as a ground, the CEC
hasn't for a long time, and I wouldn't recommend relying on
it unless there was no other alternative. Old armor can
get remarkably high resistances...
Chris Lewis, Una confibula non set est
It\'s not just anyone who gets a Starship Cruiser class named after them.
On Tue, 16 May 2006 05:01:00 -0000, firstname.lastname@example.org (Chris
It would still be plenty to trip the GFCI if you had a ground fault to
the case of attached equipment and eliminate one of the problems
mentioned here. Actually AC cable does pretty well if it was properly
installed. I did a survey of some old WWII buildings that were being
converted and all of the AC runs were <1 ohm under a test load (Ecos
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