Ok this may be a long one I need to put in some detail so this makes
I am replacing all my receptacles/switches in the house to decora. In
my living room I found through much trial and error that there is a
plug that has a live ground. It's 120V from the ground to the box.
It was isolated or not touching the box when the old receptacle is on
there, but since I have tried to put it on there, it causes a short
and trips the breaker.
I have the cct on right now, but have to pull the wires out of this
one box so the ground doesn't touch anything. The plug to the right
of this one tests fine with my little tester. (kind iwth 3 lights you
plug into receptacles).
The plug to the left is weird. It tests for "open ground" (thus
because I assume I have pulled it's ground off the other box) and it
says Hot-Ground switched. I measure 70V from line to ground wich is
weird. There are 2 cables coming into this box, and I think it must
be 2nd from the end of the cct as there is one last plug behind our
dining room hutch which I won't replace.
Can anyone tell me what could be the problem with this cicuit? I
can't figure it out. I have inspected the cables coming into the
boxes and they seem to be fine. It's been working for the past 15
year as the ground in the one box wasn't touching ground, but I of
course don't want to put it back like that.
I will help you with what I can. H/G reversed means exactly that. There may
be a problem in another upstream box that is resulting in this reading at
this box. As a test only try switching the wires in the box you have and see
if your tester reads correctly.
How many wires attached to this device? Is it in the middle of the circuit
or at the end (2 wires only attached).
I think you are going to need to identify every device on this circuit and
go through each box to isolate the problem. The only one you can never find
is a nail or screw shorting the hot to the ground outside of a box. But
then if that were the cause your ground wire must be open at some other
point in the run.
AS a general rule once you identify every device on the circuit you can
usually figure out the wire run based on proximity to the breaker box.
The "hot" ground wire must be picking up voltage from somewhere, and if the
outlet that is feeding the "problem" outlet is fine, there must be something
in the circuit between them. Maybe an outlet on the opposite side of the
===> OK. Since it trips the breaker, it's definitely live! How many, total wires, are in the box, what color, and where to they go?
===> Not sure I understand this; pull wires out of the box so the ground won't touch?
The plug to the right
===> Those are usually decent for testing outlets; good.
===> What other box? The one with the hot ground?
===> Not necessarily: You can get a reading like that when using a high input impedance meter; it reads induced voltage from other wires. It MIGHT
be perfectly normal. I'll often read 90Vac on mine, in fact.
If you plug anything into the outlet that draws even a tiny amount of
current when it runs, I'll bet you'll read 0 Vac.
If you DO NOT read 0 Vac with something connected, then there is another,
possibly serious problem. For it to be less than the 120Vac or whatever
your normal line voltage is, you could have to have something badly miswired
elsewhere. I doubt that is the case, but it's important to prove it, just
in case you have crossed wires elsewhere and when you kill that ckt brkr,
you haven't actually turned off ALL power into the ckt.
There are 2 cables coming into this box, and I think it must
===> Two cables? Do you mean two pairs of wires? If so are they black/white pairs? Is there a green or bare wire there also?
===> Maybe. The first thing to do is to figure out whether there really is 70Vac on the "ground" wire. Is there? What color is it? Where does it
connect to on the outlet? Rather, where was it connected? Is it connected
I have inspected the cables coming into the
===> Good decision. Whether it's a "spare" wire or a mis-used wire, it's fairly important to know what's up for safety's sake.
I TAKE NO RESPONSIBILITY FOR THE ACCURACY OF ANYTHING I'VE TOLD OR WILL TELL
YOU. IF IN DOUBT, GET AN ELECTRICIAN IN THERE. 120vAC CAN KILL IN LESS
THAN ONE SECOND IF IT GOES THRU THE RIGHT PLACES IN YOUR BODY.
For conversational reference, wiring annotations are as follows:
Black = "hot". This (hot) wire goes all the way back to the fusebox
eventually, and is black all the way.
white = neutral. The "other" side of the ckt. Picture it like black hot is
"in" FROM the fusebox, and white neutral is "out" TO the fusebox.
Green or bare wire = Earth Ground. Just what it sounds like, and eventually
goes to that ground rod outside the house.
Black goes to the small blade hole on the outlet.
White goes to the wide blade hole on the outlet.
Green or Bare goes to either the metal electrical box, or to the green screw
on the outlet box.
White and Green/bare are NEVER connected together ANYWHERE except all the
way back at the fusebox. Inside the breaker box, they connect together; no
place else. They MUST NOT be connected together in any outlet box.
Based on the foregoing, can you come back with:
1. Figure out whether that wire is hot?
2. Now describe the situation in terms of wire colors?
3. Add any details that seem relevant.
Once again, I have to say, ELECTRICITY KILLS AND MAIMS QUICKLY, so if you
aren't sure what your'e doing, get an electrician in there.
Yuo say you blow the breaker when you connect the box to the ground
wire and you conclude that the ground wire is somehow hot.
It could be the other way round.
The ground wire may be fine and the box may be hot somehow.
Per the symptoms you describe, someplace somehow, the black wire is
connected to something it shouldn't be connected to. Is there an
unintended connection from the black wire to box someplace? Is the
clamp so tight that it cuts into the cable and connects the box to the
black wire accidently?
This is Turtle
You might invest in a receptical analyzer or called by Radio Shack a AC Outlet
Analyzer to plug into the receptical and it will tell you what is wrong with the
wiring or the problem spell out for the very unknowning of electrical problems
from $3.00 to $6.00. Walmarts, Home Depot, Low's, and Radio Shack has these
testers. Here is one that you can look at and see about it.
http://www.radioshack.com/ go here and then type in the search area section the
number 22-141 . this number is the catalog number of this AC Outlet tester and
it will take you to it. This is the best but cost about $6.00.
Now at some stores they have a cheaper version but does not test GFI receptical
properly for $2.99 . If it is not a GFI type this will do fine too.
FWIW, I wouldn't put all my faith in the little 3 light tester. I had one
that showed a 3 prong outlet as "good" when in fact the previous owner
decided to take a 2 wire knob & tube circuit and make it "grounded" by
jumpering a small wire on the back of the outlet from neutral (or was it
hot?) to the ground prong. I only discovered this when I plugged in a new
plasma TV VGA cable into the back of an HDTV tuner and the VGA port exploded
in sparks. Everything on that circuit (TV, stereo, etc) appeared to work
correctly until that incident.
So the moral of my story, if you're getting weird voltage readings, inspect
every outlet on the circuit to be sure someone didn't jury rig something
dangerous inside a box.
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