tapping off 3 phase to 1 phase

Discussion in 'General Electronics Chat' started by mvtop, Oct 6, 2009.

  1. mvtop

    Thread Starter New Member

    Oct 5, 2009
    3
    0
    Hi,
    I have a question about using 3 phase.
    This is what i have:
    I have some AC condensers positioned on the outside of a building with the cutoffs close by. The AC's are all 3 phase.
    I need to grab some 120v 1 phase power and run a few circuits. The cutoffs for the AC are in a good location to grab power from.
    So, can I use a leg of the AC power to run a circuit if I’m not overloading the circuit?


    thanks.
    MV.
     
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
    1,066
    Single phase power is usually taken line to line in a three phase delta feed. It is usally take Line to Neutral in a Wye feed. You need to figure out what you have...
     
  3. mvtop

    Thread Starter New Member

    Oct 5, 2009
    3
    0
    hmm. ok. let me check into it more.
     
  4. gerty

    AAC Fanatic!

    Aug 30, 2007
    1,153
    304
    The 3 phase going to the ac units probably doesn't have a neutral, which
    you'll need to get the 120v. If you use the ground as a neutral, that would be a code violation. All of this is assuming you're in the US.
     
  5. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    1,571
    230
    I assume you wanted to use that 120 for something other than the condensers. Your code would not allow that.
     
  6. mvtop

    Thread Starter New Member

    Oct 5, 2009
    3
    0
    thanks for the replies.
    but after looking at this again, and the time spent hacking this into subbmission, it would be just as quick to pull a few new circuits and would up to code.

    thanks.
    MV
     
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