I've just come across about 3 or 4 wall outlets in my parent's home that are
of the style that will only receive a male plug of 2 prongs. What is
involved in replacing the box innards with the receptacle that will take the
male plug of 3 prongs (2 plus the third below and in the middle)? My
recollection from school days is that the major difference is the addition
of a ground wire to a screw in the middle of the receptacle. Or, am I
thinking of something altogether different. The rest of their house has the
3 prong receptacles so this really is a bit of a mystery.
this is very common in homes built during the 50's and early 60's. the
actual wire is 3 conductor, however, the 'electricians' back then did not
fully understand the concept of alternate grounding. often, the ground wire
was cut, left coiled in the box and generally ignored as old stocks of 2
prong outlets got used up. dad told me that grounded outlets cost ten cents
and ungrounded were six.
Remember too that most builders back then were postmen, government clerks,
etc., that moonlighted as homebuilders when the need arose.
On Sat, 14 May 2005 22:22:01 -0400, " email@example.comSOB"
I knew a guy that used the bare wire as a 3rd conductor for switched
circuits and where there were 2 circuits being fed thru one cable. He
would just wrap electrical tape around the bare wire where it entered
the metal boxes and would use it as a hot conductor. I remember him
doing that when I was a teenager, and since I was always working with
electrical stuff from about age 10 on, even I knew that was wrong.
But he didn't care, he said "it works, and thats all that matters".
This was in the 60's. His house never burned down, so I guess he was
either lucky or he just used enough tape.
If the cable supplying the receptacles has three conductors (two insulated and
one bare), you're home free: just install 3-prong (grounded) receptacles as
- black wire to gold-colored screw terminal
- white wire to silver-colored screw terminal
- bare wire to green screw terminal
and you're done.
If the cable has only two conductors (both insulated), you have two choices:
1) Leave them alone. They work. The only problem is, you can't plug a grounded
device into them.
2) Replace them with ground-fault circuit interrupter receptacles. You will
need one GFCI per circuit, installed in the location that is *electrically*
nearest the breaker box, and connected so as to protect the remainder of the
circuit (full instructions are included with the GFCI). Other 2-prong
receptacles on that circuit can be replaced with 3-prong receptacles wired as
I described above, except that you don't connect the ground wire (since there
isn't one). *** NOTE *** All of the receptacles, including the GFCI, must then
be marked "No Equipment Ground" using the sticky labels that come inside the
package with the GFCI.
Doug Miller (alphageek at milmac dot com)
Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?
He's not done, is he, until he checks to make sure that the other end of the
bare wire(s) is attached to the proper place in the panel, and is actually
acting as it should? You never know what someone has done ahead of you. An
$8 circuit tester to check all the receptacles in the house might be smart,
just to see if they are wired correctly. It's a cheap, self-empowering
investment. They are also handy just to see if a circuit is live.
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