Questions about Splitting 3/P

Discussion in 'The Projects Forum' started by pmiller87, Aug 9, 2010.

  1. pmiller87

    Thread Starter New Member

    Aug 9, 2010
    I am looking for a little help with a project I am working on.

    I have 230V 3P (30Amp) power source and want to power equipment using 120V S/P. How do I hook it up?

    Since this is only a 30 amp circuit, am I limited to 10 amps per leg or can I pull 30 amps per leg…or is there a calculation I need to perform to get the max draw.

    Thanks for you help
  2. gerty

    AAC Fanatic!

    Aug 30, 2007
    You'll need a neutral, you didn't mention if it was 4 wire ( 3 phases and a ground) or 5 wire (3 phases, a neutral, and a ground).
  3. pmiller87

    Thread Starter New Member

    Aug 9, 2010
    The system I am working with is a 4 wire system.

    Hooking to ground on an AC circuit is not something I think I should be doing.
    Last edited: Aug 9, 2010
  4. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    You should hire an electrician
  5. marshallf3

    Well-Known Member

    Jul 26, 2010
    230V implies a high-leg Delta 3 phase system in which there is 240V across any two of the three phase legs, 120V to neutral on two of them and around 169V or more to neutral on the third one.

    Find which leg is the "high leg" and ignore it, you can then use either of the other two to supply 120V to neutral.

    It will probably make more sense if you read through this:

    Oh, and 30A is 30A here.
    Last edited: Aug 9, 2010
  6. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    Ground, or more specifically bond, is typically not quoted as a member of the service, so the question requires clarification. Is your 4th wire neutral, or bond?
  7. AlexR

    Well-Known Member

    Jan 16, 2008
    To me a 3 phase 230Volt 30Amp system implies that you have 3 phases and each phase is at 230 Volts and each phase capable of delivering 30 amps. If this is the case then you will need to install a transformer to run your 120Volt device.
    In any case a qualified electrician will be able to make the proper connections.

    If you have to ask about mains wiring then you should not be touching it as you obviously don't know what you are doing. Incorrectly installed mains wiring can kill not only yourself but also innocent users.