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Thread: 120/240 v single phase panel

  1. #1
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    120/240 v single phase panel

    Can a 120/240v single phase panel be powered from 120/208v three phase panel with 120/208V three phase power? Does the code allow?

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  2. #2
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    Quote Originally Posted by codequestion View Post
    Can a 120/240v single phase panel be powered from 120/208v three phase panel with 120/208V three phase power? Does the code allow?

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    I think you'd need a single phase 120-0-120 transformer.
    Si hoc legere scis nimium eruditionis habes.

  3. #3
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    Yes, it is considered a 120/208Y; with that said, your 2pole loads must be capable of operation at 208V. If 240V is needed than as stated a transformer would be required.
    "Just because you're paranoid, doesn't mean they're not out to get you"

  4. #4
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    Quote Originally Posted by Besoeker View Post
    I think you'd need a single phase 120-0-120 transformer.
    And why would you need that?

    JAP>

  5. #5
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    Quote Originally Posted by kingpb View Post
    Yes, it is considered a 120/208Y; with that said, your 2pole loads must be capable of operation at 208V. If 240V is needed than as stated a transformer would be required.
    I think he's wondering about the voltage rating issue with the 240v panel being fed off of a 2p breaker in the 3ph panel.

    You actually do not have 120/208 Y at the subpanel if it's fed that way.

    JAP>

  6. #6
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    Quote Originally Posted by jap View Post
    I think he's wondering about the voltage rating issue with the 240v panel being fed off of a 2p breaker in the 3ph panel.

    You actually do not have 120/208 Y at the subpanel if it's fed that way.

    JAP>
    All is new work. Transformer secondary is 208v/120v feeding 208/120v panel three phase. Feeder breaker from 208v feeds 240/120 V panel. I think as mentioned by someone here earlier 240/120v panel can be used in 208/120v as long as there is no 240v loads.

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    Last edited by codequestion; 04-12-18 at 03:50 PM.

  7. #7
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    Quote Originally Posted by jap View Post
    And why would you need that?

    JAP>
    To get 120-0-120 Volts.
    Si hoc legere scis nimium eruditionis habes.

  8. #8
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    Quote Originally Posted by Besoeker View Post
    To get 120-0-120 Volts.
    And why would you need that if the panel is fed 120/208v 1ph from a 120/208v Y 3ph panel?

    JAP>

  9. #9
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    Quote Originally Posted by jap View Post
    And why would you need that if the panel is fed 120/208v 1ph from a 120/208v Y 3ph panel?

    JAP>
    There would be no 240V - see the thread title.
    Si hoc legere scis nimium eruditionis habes.

  10. #10
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    [QUOTE=codequestion;1909520]All is new work. Transformer secondary is 208v/120v feeding 208/120v panel three phase. Feeder breaker from 208v feeds 240/120 V panel. I think as mentioned by someone here earlier 240/120v panel can be used in 208/120v as long as there is no 240v loads.

    I just am not sure where in code it says that.





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