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    jonnynach's Avatar
    jonnynach Posts: 2, Reputation: 1
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    #1

    Jun 26, 2011, 05:58 PM
    How do I test which wire is hot and which is nuetral when I have two blacks and grnd?
    I'm trying to wire my pool pump
    hkstroud's Avatar
    hkstroud Posts: 11,929, Reputation: 899
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    #2

    Jun 26, 2011, 06:25 PM

    What is the voltage? Two black wires indicate 240 volts meaning that both are hot and there is no neutral. A meter should show 120 volts between each black and the ground.
    ma0641's Avatar
    ma0641 Posts: 15,675, Reputation: 1012
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    #3

    Jun 27, 2011, 12:59 PM
    Sounds like you have a 240VAC supply and there is no Neutral. What is the pump voltage? If it is 120VAC, open the breaker box and see if you do have 240, a double breaker. If so, and the pump is 120 VAC, disconnect one of the blacks, connect it to the neutral bar, wrap white tape around it at the panel and at the pump and you have 120VAC. Would be better to get a Single pole breaker, for the amperage you need, replace the double and close the open slot.
    ballengerb1's Avatar
    ballengerb1 Posts: 27,378, Reputation: 2280
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    #4

    Jun 27, 2011, 01:32 PM

    Based on the question and your description lets start by pulling the breaker. Now tell us what the breaker label says or what it looks like. This could well be 240 vac but you aren't sure exactly what's going on here so lets be safe. What was connected to this outlet before, what does the receptacle look like?
    jonnynach's Avatar
    jonnynach Posts: 2, Reputation: 1
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    #5

    Jun 27, 2011, 04:23 PM
    Thanks for everyone's input!

    I just may have 240 volts, when I use the voltmeter to test between the ground and both blacks I get 120 each time. When I use the voltmeter between the two blacks I get nothing, indicating they are both hot...

    I'm just nervous about connecting one of the hots to the nuetral bar on the pump, will this fry the pump?
    donf's Avatar
    donf Posts: 5,679, Reputation: 582
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    #6

    Jun 27, 2011, 06:12 PM

    Jonny,

    If you have your meter set up properly and you measure between the two wires, you should read 240V, certainly not nothing.

    If you are reading nothing, then you may have an incorrectly wired 240 VAC breakers.

    Instead of the breakers on different phases (one on top of the other), they are side by side. You really need to get inside that panel and tell us what is there or attach pictures for us to look at.
    Stratmando's Avatar
    Stratmando Posts: 11,188, Reputation: 508
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    #7

    Jun 27, 2011, 06:22 PM

    I would pull the panel cover, determine the circuit/breaker, wires coming out of the panel, and where they are attached inside.
    With both blacks hot, and zero between the both does need to be checked out.
    Check for 240 volts going into panel, and 240 volts is available at the breaker.
    hkstroud's Avatar
    hkstroud Posts: 11,929, Reputation: 899
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    #8

    Jun 27, 2011, 07:18 PM

    Something doesn't smell right.
    First read the nomenclature tag on the motor.

    You said,
    I'm trying to wire my pool pump
    You didn't say your were replacing the motor.

    Who did installed the wiring.

    Post back with more information about what you are doing and have done. We don't want to see you blow your motor up or get hurt. Pools require special attention to grounding.

    I'll bow out to TK or Stan.
    Stratmando's Avatar
    Stratmando Posts: 11,188, Reputation: 508
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    #9

    Jun 28, 2011, 05:04 AM

    Til TK or Stan gets here, You do need to verify the wire is correct size for the motor, breaker is correct size to protect the wire, and the voltage.
    2 blacks having 120 volts to ground and nothing between the 2 is not 240 volts.
    If 120 volts is what you need, you will need to tape one of the blacks with white tape and connect to the neutral bar.
    Then go to the other end and see which of the 2 blacks has voltage off ground, this wire remains black, and the 1 with zero voltage between itself and ground is the neutral and also needs to be identified with white tape.
    tkrussell's Avatar
    tkrussell Posts: 9,659, Reputation: 725
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    #10

    Jun 28, 2011, 07:46 AM
    John, based on this statement:

    Quote Originally Posted by jonnynach View Post
    I just may have 240 volts, when I use the voltmeter to test between the ground and both blacks I get 120 each time. When I use the voltmeter between the two blacks I get nothing, indicating they are both hot...
    Seems that you clearly do not have a good understanding of what your working with.

    We need to know:

    Horsepower of motor
    Voltage rating on Nameplate of motor
    Type of circuit breaker you have, a photo would be great.
    Size of all conductor you have.

    Others have asked for this detail, and you have not responded.

    In my opinion, I would suggest you hire an electrician to wire your pool. Not only do you not know how to use a volt meter, there are many other code issues with wiring a pool, I am sure you are not aware of.
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