I have one of those gadgets that looks like a plug in with 3 lights on
According to the lights, I have a "Open Ground".
What is that?
I think it means that I have a ground wire unhooked, but I cannot find
one that looks like it is.
Would it not being grounded to earth also be an open ground?
The meter is grounded to earth, but the breaker box in the house is not
grounded to earth.
Also, the trailer skin its self may also not be grounded to earth.
Any help would be appreciated.
It means the ground (bare or green wire (usually)) is not connected to
three prong plug installed in an 'ungrounded' circuit (circuit with
only a hot and a nuetral)
bad receptical - unlikely
broken wire - unlikely
in any one of the junction boxes leading to that outlet the ground is
ground not connected inside breaker box - unlikely
start with pulling the outlet and work your back to the main box from
The key piece of information here is the word "trailer". I would be
very surprised if your trailer was wired with ungrounded wire, but your
meter may not be grounded correctly, or the tester may not be
sophisticated enough to test a trailer circuit. Everything should be
grounded thru the "main" panel (actually it is a subpanel) but the
neutral should be insulated from ground at this point. Neutral and
ground are connected at a point external to the trailer
If your trailer is connected by a 50A cord, you may have the plug wired
incorrectly and all your grounds are floating. Or maybe you are running
this off a generator and the generator neutral is not bonded to its frame.
That's all I got. I'll let the real electricians take it from here; I'm
not that familiar with Article 550 of the code.
Here is how the breaker box is wired.
Black wire = breaker.
White wire & copper wire on ground bar.
Is there two ground bars?
Is one a case ground, while the other one is not a case ground but a
Can you tell me the correct wiring of the breaker box.
It is a trailer house that is wired direct to the meter and not threw a
Further symptoms is that when you turn on the AC window unit, the fan,
the fan will run but the AC compressor will not come on.
Then the AC burned out.
Also, when a refrigerator was plugged into a separate breaker, it
instantly over heated a channel changer and a fan to the point that
they were dead permanently.
If I were to make a wild unqualified guess, I would say you have a loose
neutral wire somewhere between your panel and the utility pole. This is
a very dangerous situation. Whether I'm right or not, you need to get
an electrician (or at least the utility company) to look at it.
I think you are still supposed to have your ground interconnection at
the meter instead of in your panel, then 4 wires from the meter's
disconnect to the house instead of the usual 3 wires.
If there is only one 'bar' it's typically called the 'neutral bar'. If
all the wires in the box look ok, no dangling wires, loose screws,
etc. Then I would start at the receptacle diagnosing the problem.
I'm not sure how having an open ground could cause individual
components of the AC to not work, so it might be a seperate issue.
As for using an AC with an open ground..... so many people have hurt
themselves that way, I've been hearing that future AC units will have
a 'current leakage' detector built in. Like a GFCI on the plug.
Be careful and get a qualified electrician involved.
First the 'ground' at your receptacle is an "eqiupment grounding
conductor" so it actually should run back to the main panel, and
should tie into either the neutral bar, or a ground bar bonded to your
Back to your question, it sounds like you have a 'break' in
continuity, also called an 'open circuit" or this case an "open
ground". Now this could be that your equipement grounding conductor
isn't installed properly, broken, or nonexistant. What is the wiring
method (knob and tube, romex without ground, romex with ground, AC,
etc) in you house? When was it built?
Now the 'grounded to earth', grounding to earth isn't for 'grounding'
applicances, or items plugged into receptacles, but to stablize
voltages at your panel (and in the network of panels) during voltage
Now this couldl be too much information, but then not enough. I am
not there to look at your circuit/panel/etc. So just guesses basedon
my understanding of the NEC, and you should seek help of an electrican
If you have an open neutral outside the trailer, the tester may also say you
have an open ground, or may say you have open hot, depending on what other
appliances are turned on. In other words, if you have an open neutral
outside, the tester is going to give you confusing indication.
Like the other poster said, an open neutral is very damaging. You could
potentially burn out everything except one appliance.
To check whether you have open neutral outside the trailer, turn off all
breakers. Then connect a light bulb (1W to 100W, pick smaller one) between
black and white, and the other black (or red?) and white. The bulb should
glow normally on both circuit. If it does not glow, or if it burns out,
there is something wrong with the neutral outside your trailer.
Where to connect the ground wire to the ground rod is a different issue
unrelated to your problem. You should look up the code and verify it after
you solve the current problem.
Trailers have very strict electrical requirements when it comes to
grounding. It was not always so. During the 1950's and early 60's,
there were many electrocution incidents of people touching the surface
of an energized, not-properly-grounded trailer. The code was changed
because of this.
This, combined with the possibility of an open neutral (as mentioned
above) would justify investing in a licensed electrician to have a
look at your situation and take corrective steps, if necessary.
Avoid amateur electricians and unlicensed handymen who just "think
they know" how a trailer should be wired. You'll just get yourself
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