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Thread: 220.61 exception

  1. #1
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    220.61 exception

    220.61 (A) exception says for 3 wire 2 phase. Does this include 120/208V single phase derived from trough 120/208v three phase? It would have 2 phase.

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  2. #2
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    Instead of each one of us grabbing our Code books for all your questions, please take the time to cut-and-paste it into your question. Let's all get on the same page with the exact wording of the exact year Code you are using.

    What does "derived from trough 120/208" mean? Is that another typo? These questions would probably be easier and more accurate to ask if they weren't from your phone.

    What are you calling 2-phase?

  3. #3
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    Quote Originally Posted by MAC702 View Post
    Instead of each one of us grabbing our Code books for all your questions, please take the time to cut-and-paste it into your question. Let's all get on the same page with the exact wording of the exact year Code you are using.

    What does "derived from trough 120/208" mean? Is that another typo? These questions would probably be easier and more accurate to ask if they weren't from your phone.

    What are you calling 2-phase?
    Tapped from trough. The 2 phas 3 wire is wording from nec 2014 text.

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  4. #4
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    Sorry ignore previous post. Thats the wording coming from nec 2014.



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  5. #5
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    Quote Originally Posted by codequestion View Post
    220.61 (A) exception says for 3 wire 2 phase. Does this include 120/208V single phase derived from trough 120/208v three phase? It would have 2 phase.
    No, that reference is for a 2-phase system not single phase from a 3 phase system.
    Rob

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    All responses based on the 2014 NEC unless otherwise noted

  6. #6
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    Quote Originally Posted by infinity View Post
    No, that reference is for a 2-phase system not single phase from a 3 phase system.
    What are these 2 phase system 120/240v or 120/208v?

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  7. #7
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    Quote Originally Posted by codequestion View Post
    What are these 2 phase system 120/240v or 120/208v?

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    A two phase system has at least two phase conductors whose phasors differ by 90 degrees.
    It can be two hot and one "neutral" where L1-N is offset 90 degrees from L2-N.
    Or it could be four wire "square" with no neutral conductor and 90 degree rotations as you go around the square.
    Or it could be a star with four hots and a common neutral.
    Or a couple of other unlikely combinations in between. The common thread is the 90 degree phase rotation.
    The star configuration can be looked at as two crossed three wire single phase 120/240 systems with both neutrals sharing a wire.

  8. #8
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    Quote Originally Posted by GoldDigger View Post
    A two phase system has at least two phase conductors whose phasors differ by 90 degrees.
    It can be two hot and one "neutral" where L1-N is offset 90 degrees from L2-N.
    Or it could be four wire "square" with no neutral conductor and 90 degree rotations as you go around the square.
    Or it could be a star with four hots and a common neutral.
    Or a couple of other unlikely combinations in between. The common thread is the 90 degree phase rotation.
    The star configuration can be looked at as two crossed three wire single phase 120/240 systems with both neutrals sharing a wire.
    Nope, I told you all since I have never seen it, do not like it, and is confusing:

    Two phase does not exist.

    It nothing more than a conspiratorial plot to drive me bonkers......
    "Electricity is really just organized lightning." George Carlin


    Derek

  9. #9
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    Quote Originally Posted by GoldDigger View Post
    A two phase system has at least two phase conductors whose phasors differ by 90 degrees.
    Sott and Le Blanc connections are usually two phase.
    Si hoc legere scis nimium eruditionis habes.

  10. #10
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    Quote Originally Posted by Besoeker View Post
    Sott and Le Blanc connections are usually two phase.
    One of these?

    Name:  Scott-T.JPG
Views: 45
Size:  24.9 KB
    "Electricity is really just organized lightning." George Carlin


    Derek

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