What does it mean...?

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Old 03-20-07, 12:50 PM
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What does it mean...?

...when you have an outdoor outlet supplied by a buried UFC cable from the house main panel, and you can read voltage from the hot wire (at the outlet location), but when you plug in say a power tool, it doesn't work???? It worked no problem last summer with no work done in between to the wire or panel anyway.

Could that mean that maybe the neutral wire hase been compromised maybe like shorted or cut somewhere along the line?

Wires are properly connected to the breaker panel haivng never been touched. How would you use a volt meter to check this problem?
 
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Old 03-20-07, 12:53 PM
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The term "read voltage from the hot" is ambiguous. Can you clarify EXACTLY what you mean? Exactly what test instrument did you use and exactly how did you use it?

You need to wires to get power. A hot and a neutral. Even if the hot wire is hot, you can get no power unless the integrity of the neutral wire is also good.

Answer the question above, and we can go from there.
 
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Old 03-20-07, 01:11 PM
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I used one of those handy "pen style" voltage checkers that when you touch or place it near a hot wire it chirps loudly with a blinking light repeatedly even when near to a hot wire, and has been very reliable in several instances.

The whole cable itself is a UF 12/3 (I think) with a red, black, and a white. I disconnected the red wire at the main panel to make it a dedicated 120v line vice the fomer 240V about three years ago. The line used to feed my dock. I located the cable's path near my deck, dug it up, cut it and placed a 120v outlet there for tools, rope lighting etc (making use of an exisiting line). Worked fine up until now. I replaced the outlet first thinking it simply went bad over the winter from corrosion, but still no luck. As mentioned above, the little tool i have gives me a strong "chirping/blinking" on or around the black wire. None on the disconnected red or neutral.
 

Last edited by Boater59; 03-20-07 at 01:58 PM.
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Old 03-20-07, 01:41 PM
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So far you have not verified power, but rather you have verified that the hot wire is hot.

Use an analog meter or a two wire tester and test between the hot wire and the ground wire and between the hot wire and the neutral wire.
 

Last edited by racraft; 03-20-07 at 01:52 PM.
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Old 03-20-07, 01:50 PM
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It's pretty clear that you have an open neutral. The white wire is disconnected at either end, or broken underground. Follow Bob's directions to confirm.
 
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Old 03-20-07, 01:56 PM
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Scoping out the other post, You may not need that ckt much longer.

But it does sound like an open neutral. However, those tik tracers will read thru a Tripped GFCI. So try the 2 wire tester to confirm wether there is a neut or not.
 
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Old 03-20-07, 02:05 PM
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I was planning on keeping that circuit just for the outlet at the deck location which is roughly 75 feet form the new dock sub-panel location. Broken/cut wire wire would pretty much kill that as I wouldn't replace it.

My volt-meter has crapped out (sort of got crushed in the shed). Guess now's the time to go get a replacement. I'll report back with my results once done....Thanks
 
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Old 03-21-07, 02:33 PM
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Okay one final 3 part question looking ahead after I get my new meter, just to be sure no operator error, and I understand what my results mean.

Using the 2 wire meter:

1) What position do I place the meter selector on?

2) When checking hot to ground, what does it mean if I read voltage, and/or if I read no voltage?

3) Same question when checking the hot to neutral?
 
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Old 03-21-07, 02:57 PM
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Hard to say since we don't know exactly what your "2 wire meter" is.

But if it has a 250V AC volts setting, put it there.

If you read 120 volts between hot and ground, it means you have voltage between these two wires (seriously--that's all you really know for sure). But the logical inference is that the grounding wire has a good connection to the ground at your panel, and that the hot has a good connection to the breaker, and that the breaker is on and working.

If you read some other crazy value, like 67 volts, then you're reading phantom voltage (google it), and you most likely have a broken or disconnected wire or open breaker.

If you read no voltage, then one wire or the other is broken or disconnected, or the breaker is off, or both wires are grounded, or both wires are hot.

Same answers for hot to neutral.

From the two readings taken together, you can draw other inferences:
(A) If both readings are 120 volts, then everything is probably working fine.
(B) If neither reading is 120 volts, then the breaker is probably off or the hot wire is disconnected somewhere or broken, or all three wires are hot (this last condition is very unlikely, but don't bet your life on it).
(C) If hot to ground is 120 volts, but hot to neutral is not, then you probably have an open neutral.
(D) If hot to neutral is 120 volts, but hot to ground is not, then the grounding wire is probably broken or disconnected.

You might consider taking one more set of voltage readings. Stick one probe in the dirt at your feet, and put the other probe one at a time on each of the three wires. Ideally, only the hot wire should read 120 volts.
 
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Old 03-22-07, 11:17 AM
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Perfect! Exactly the kind of answer I was looking for. Thanks John for the lesson.
 
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Old 03-28-07, 11:57 AM
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Well I tested the line as described and I got readings of approx. 26 volts on hot to neutral/ground. Basically the same when sticking the meter pin in the ground at my feet as well. Guess it means the lines somehow have shorted out underground somewhere and are now useless.
 
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Old 03-28-07, 12:16 PM
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Does "hot to neutral/ground" mean "hot to neutral" or "hot to ground" or both hot to neutral and hot to ground (two separate tests)?

Remember the rule. Treat 26 volts the same as zero.

And no, they aren't "shorted". They are "open".

If "hot to the dirt at your feet" also reads 26 volts, then the hot isn't hot. But you didn't really specify exactly where your other probe was when one probe was in the dirt.

Without precision in language, we know nothing.
 
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Old 04-05-07, 09:27 AM
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Yes separate tests with red voltmeter lead to hot wire, and black lead to neutral. Then same with black lead to ground wire. Then I stuck the black lead in the dirt as suggested.

I went in and re-checked that the wires were connected good at the breaker in the house and that it was in fact on.
 
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Old 04-05-07, 01:12 PM
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Okay then, is there perhaps a GFCI somewhere, maybe inside the house before the cable goes outside, that is tripped? Unless the underground cable is completely severed, it does not look a lot like a problem underground.
 
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Old 04-11-07, 08:27 PM
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No GFCI or connections in between. It's a UF cable that runs direct fomr the house panel outside underground. It used to go to my dock but shorted out some time ago. So I came across it while planting a bush adjacent to my new deck and decided to cut it there and place an outside receptacle and make use of it. Worked great for a year, now this? Only thing I can think of is that it shorted again between the outlet and the panel and is now useless to me?
 
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Old 04-12-07, 07:47 AM
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I predict that some time in the distant future, you'll find the GFCI that you previously did not think existed.
 
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