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Thread: Better pop quiz

  1. #1
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    Better pop quiz

    Newbies .... Walk up to OD unit and after checking current across the contactor terminals comming in you get 160 155 110 162 125 fluxuating all around on meter, checking line 1 to ground you get 120, line 2 to ground you get 40 volts.

    Whats going on here ????




    One for the Pro's .... walk up to a different unit , different neighborhood, and get 120 line 1 , 0 line 2 , go to main panel and get 120 , and 0 when checking to ground and neutral at MAIN breaker.

    What tha hell ....

  2. #2
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    I don't really know whats with the tests. But for the second one possible bad breaker or only one leg total coming into the house. Had that at my house just 3 days ago. One leg burned up at the transformer on the pole.

    Here is one for you,
    Will a 240-24volt transformer convert enough voltage to pull in a 24 volt contactor if it is only getting 120 volts to the supply side of the transformer?

  3. #3
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    What reading did you get from the other 120 leg when it was disconnected from transformer?

  4. #4
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    Quote Originally Posted by Snapperhead View Post
    ............One for the Pro's .... walk up to a different unit , different neighborhood, and get 120 line 1 , 0 line 2 , go to main panel and get 120 , and 0 when checking to ground and neutral at MAIN breaker.

    What tha hell ....
    One possible situation is the electrician wired the main panel wrong. He got L1 on one breaker and L2 on the adjacent breaker. Happened to come across this, this past summer. L1 wired to 40 amp AC breaker and L2 wired to 60 amp electric range breaker. Both breakers on and 240V at outside disconnect. AC breaker off and range breaker on and only 120V at disconnect.
    The picture in my avatar is of the Houston Ship Channel and was taken from my backyard. I like to sit outside and slap mosquitos while watching countless supertankers, barges and cargo ships of every shape and size carry all sorts of deadly toxins to and fro. It's really beautiful at times.....just don't eat the three eyed fish....

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  5. #5
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    Snap, is this a way to get answers to the issues YOUR having? lol

    Im just asking cuz it said in your profile, your part time hvac...???

    Plus you never even gave YOUR answer as to what YOU would do for the 1st test?

    ...waiting still??? LMAO

    Just jokin wit ya, but dam man..."what would snapper do?"
    “If I have seen further than others, it is by standing upon the shoulders of giants.” ~ Sir Isaac Newton


    I'm learning all the time, the tombstone will be my diploma!!!


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  6. #6
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    Quote Originally Posted by Cooked View Post
    One possible situation is the electrician wired the main panel wrong. He got L1 on one breaker and L2 on the adjacent breaker. Happened to come across this, this past summer. L1 wired to 40 amp AC breaker and L2 wired to 60 amp electric range breaker. Both breakers on and 240V at outside disconnect. AC breaker off and range breaker on and only 120V at disconnect.
    Thats funny because i've seen this too in a restaurant where the owner did his own wiring

    But the answer i was looking for was what FL HVAC said ... and he got lucky enough to see it first hand 3 days ago.

    There are fuses at the elec pole outside.

  7. #7
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    Quote Originally Posted by Tommy1010 View Post
    Snap, is this a way to get answers to the issues YOUR having? lol

    Im just asking cuz it said in your profile, your part time hvac...????
    Been doing it part time for 9 years. I've seen a thing or two




    Quote Originally Posted by Tommy1010 View Post
    Plus you never even gave YOUR answer as to what YOU would do for the 1st test?
    Im not going to just give you the answer without you first guessing there buddy.
    I know the answer because ive seen it several times , do you ?

  8. #8
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    Quote Originally Posted by Snapperhead View Post
    Been doing it part time for 9 years. I've seen a thing or two

    I know you have..I can tell by the questions..lol


    Im not going to just give you the answer without you first guessing there buddy.
    I know the answer because ive seen it several times , do you ?

    For this one, i havent even really read it. For the other one, I misread it, and actually didnt realize the part where you said..NOTHING was running. So I retract my answer from that one. LMAO...
    “If I have seen further than others, it is by standing upon the shoulders of giants.” ~ Sir Isaac Newton


    I'm learning all the time, the tombstone will be my diploma!!!


    Did you ever stop to think, and forget to start again?

  9. #9
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    First of all, how do you check CURRANT with a VOLTMETER????????

    For the first situation, I would say that the house has a loose neutral and that the VOLTAGE is fluctuating due to varing electrical loads within the house.

    In the second situation, you have lost power on one leg of the 240/120 volt service to the house. You could also possibly read a lower voltage (leg to neutral) on the "dead" leg if a 240 volt device was operative and feeding through the device to this leg. However, in this instance, you would not read any voltage from the "hot" leg to the "dead" leg.

  10. #10
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    Quote Originally Posted by Bill Lee View Post
    First of all, how do you check CURRANT with a VOLTMETER????????

    For the first situation, I would say that the house has a loose neutral and that the VOLTAGE is fluctuating due to varing electrical loads within the house. .
    There is no neutral in a 240 device.

    And its CurrEnt

    Ok how about Voltage and not current (amps).... but you know what i meant.



    Quote Originally Posted by Bill Lee View Post
    In the second situation, you have lost power on one leg of the 240/120 volt service to the house.
    Correct





    Quote Originally Posted by Bill Lee View Post
    You could also possibly read a lower voltage (leg to neutral) on the "dead" leg if a 240 volt device was operative and feeding through the device to this leg. However, in this instance, you would not read any voltage from the "hot" leg to the "dead" leg.
    Again ... no neutral on 240 , and if you had the problem i stated above , yes you would have voltage reading hot leg to hot leg, but fluxuating all over.

    ALTHOUGH you would be correct in what you are saying though ""if"" one leg was dead in YOUR scenerio, there would be a reading of 0 across both legs.

    The one leg Im talking about in the quiz has 40 volts reading on the (Multimeter) to ground , and the other 120 to ground, but fluxuating voltages across both legs.

    BUT.... what i think you meant to say ... if you have a 240 volt system and you are checking power at the contactor with it calling , you will read 120 on both sides to ground because it going through the device, even if one leg is dead from the disconnect.

    Unhook the wires from contactor and (if you lost a leg totally like say through a fuse) you will have one dead leg to ground reading 0 , and one reading 120to ground , and 0 across both.
    Last edited by Snapperhead; 10-06-2011 at 09:50 AM.

  11. #11
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    Quote Originally Posted by Snapperhead View Post
    Newbies .... Walk up to OD unit and after checking current across the contactor terminals comming in you get 160 155 110 162 125 fluxuating all around on meter, checking line 1 to ground you get 120, line 2 to ground you get 40 volts.

    Whats going on here ????




    One for the Pro's .... walk up to a different unit , different neighborhood, and get 120 line 1 , 0 line 2 , go to main panel and get 120 , and 0 when checking to ground and neutral at MAIN breaker.

    What tha hell ....
    Quote Originally Posted by Bill Lee View Post
    First of all, how do you check CURRANT with a VOLTMETER????????
    .
    '


    That's were I was confused as well. So you were saying check voltage across the contactor right?

  12. #12
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    I will admit, the places i've seen this problem has been where a store owner , or homeowner tries to do their own work and doesnt understand you must get everything tight when messing with electrical stuff, whether you rig it , or go by code, and make sure its water tight as well.

  13. #13
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    FLHVAC- "Will a 240-24volt transformer convert enough voltage to pull in a 24 volt contactor if it is only getting 120 volts to the supply side of the transformer? "
    NO

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