What does a breaker do when it goes bad?

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  #1  
Old 08-08-05, 04:17 PM
lostinthejungle
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What does a breaker do when it goes bad?

I was here two weeks ago with a problem regarding my new table saw and not enough Amps on a 20 amp circuit to run it. I was using a cheap 100 ft extension cord, and changed to a 12/3 25 foot and things workd OK yesterday, and then the breaker started breaking and today the saw won't even get going before the breaker breaks.

Could I have messed up the breaker? (I have a refrigerator on that circuit (when I'm not using the saw and it still works.) Maybe the switch on the saw short circuited? Any thoughts? I've only got an hour on the saw, max.
 
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  #2  
Old 08-08-05, 05:18 PM
Eddiebx
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have u tried pluggin the saw directly to the wall on another circuit?

could be the saw for all you konw, maybe an internal short
 
  #3  
Old 08-08-05, 06:33 PM
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If the extension is coiled up for the unused part stretch it out.
 
  #4  
Old 08-08-05, 07:50 PM
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Sorry, but you're going to have to find another circuit for the refrigerator (or for your saw). The refrigerator cycles on and off automatically. If you're lucky and it doesn't cycle on while you use the saw, it works okay. But if you're unlucky and it does cycle on while the saw is in use, you trip the breaker. This isn't good for you, it's not good for your house, and it's not good for your refrigerator.
 
  #5  
Old 08-09-05, 12:25 AM
Eddiebx
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oh yeah one thing i found out the hard way is, its very bad for a fridge to leave it plugged in to a receptacle with the circuit breaker in the off position.

it seems that there will still be a very low voltage present, which willl overheat the compressor and kill it if you leave it plugged in like that too long

not really pertinent to the topic but a cool fact i learned the hardway
 
  #6  
Old 08-09-05, 04:09 AM
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Originally Posted by Eddiebx
oh yeah one thing i found out the hard way is, its very bad for a fridge to leave it plugged in to a receptacle with the circuit breaker in the off position.

it seems that there will still be a very low voltage present, which willl overheat the compressor and kill it if you leave it plugged in like that too long

not really pertinent to the topic but a cool fact i learned the hardway
This makes no sense whatsoever. A properly functioning circuit breaker in the off position means no current and no voltage.
 
  #7  
Old 08-09-05, 07:03 AM
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I tend to agree with RAC on this as once the breaker is off the circuit should be " DEAD" unless you have yourself a faulty breaker or a neutral issue...but regardless the intent of a breaker is to stop the voltage so again I would have to ask where you received this fact....other than the unit was probably going anyway.
 
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Old 08-09-05, 07:52 AM
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Agreed. I think this "cool fact" is so cold that it's dead.
 
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Old 08-09-05, 09:50 AM
Eddiebx
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darn really? i always thought unless you unplug it from the wall, theres still some voltage traveling through the neutral, enough to kick the compressor over and over till it burns out.

thats what the fridge repair man told me when he came to replace the compressor. something about a low voltage causing the compressor to want to start repeatly, thus over heating it
 
  #10  
Old 08-09-05, 09:52 AM
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If that really happened to you, then you need to get an electrician to come out and remedy the hazard in your house wiring. It's not normal.
 
  #11  
Old 08-09-05, 11:09 AM
Eddiebx
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ok i just went downstairs and checked at the breaker box. pretty much all of the breakers will have about 3-4 volts with respect to neutral when off. does that mean the breakers are leaking current, they are i woudl estimate 25yrs old?
 
  #12  
Old 08-09-05, 11:18 AM
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Are you measuring with a digital voltmeter?
 
  #13  
Old 08-09-05, 11:26 AM
Eddiebx
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yes i am using a fluke dmm
 
  #14  
Old 08-09-05, 12:26 PM
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Digital voltmeters are too easily influenced by phantom voltage. The reading is not reliable. The problem is that a small static charge can make the voltmeter think that there is voltage there.
 
  #15  
Old 08-09-05, 12:49 PM
Eddiebx
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hmm....so there really isnt any charge on there? or there is?

most importantly, do you think the breakers need replacing?
 
  #16  
Old 08-09-05, 01:39 PM
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You use the terms "charge", "voltage" and "current" interchangeably. These mean very different things. There is probably a very small charge. The voltage is there, but it's not coming from the breaker--it's being induced by nearby wires--and it carries virtually no power behind it. Even though you read 3 volts on your voltmeter, you would not be able to connect and run a device that ran on three volts there. There is no current since the circuit is open, and if the circuit ever were to close, both the voltage and charge would instantly disappear.

And no, I don't think the breakers need replacing.

Try this. With the breaker off, take a reading from your neutral wire to a known good ground (not to the hot wire). That should tell you how much voltage is really on the neutral with the breaker off.
 
  #17  
Old 08-09-05, 02:57 PM
Eddiebx
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so i should go measure the voltage at the receptacle in question, and measure between the neutral wire and a ground?

you said that the voltage showing up on the DMM is caused by induction from near by wires, but what if i measure directly at the breaker, on a breaker that is not connected to any wire. cuz i stuck in one of the old breakers and measured directly at the screw, with respect to neutral and still got a voltage reading
 
  #18  
Old 08-09-05, 07:15 PM
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Do not use your DMM. It is giving you inaccurate readings. The voltages are meaningless because of the EM (electro-magnetic) field created by the other wires.
 
  #19  
Old 08-10-05, 06:53 AM
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Measuring it directly at the breaker will not be any better.

If you want another test, stick the two probes of your voltmeter into a potato or an apple. It will register a couple of volts there too. But I don't think the potato is dangerous either, nor will the potato kick over the compressor on your refrigerator.

Disclaimer: The voltage you read from the potato is not caused by the same thing as the voltage you read from the breaker. But the idea is the same: voltage is not a problem in the absense of any significant power.
 
  #20  
Old 08-10-05, 03:41 PM
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P.S. No LIVE potato's were harmed in any way, shape or form in this experiment for all the potato activists out their.
 
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