Open Ground

Open Ground
I have one of those gadgets that looks like a plug in with 3 lights on it. 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.
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CanopyCo wrote:

It means the ground (bare or green wire (usually)) is not connected to ground. could be: 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 not connected ground not connected inside breaker box - unlikely
start with pulling the outlet and work your back to the main box from there.
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CanopyCo wrote:

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.
Bob
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zxcvbob wrote:

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 neutral?
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 plug.
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.
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CanopyCo wrote:

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.
Bob
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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.
imho,
tom
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If all of the receptacles show the same thing it is probably a missing main bonding jumper in the service.
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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 neutral bar.
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 transients.
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 for help.
imho,
tom
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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.
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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 into trouble.
Beachcomber
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1. Read the instructions that came with your device. 2. Buy a cheap ohmmeter and measure the actual resistance to ground.
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