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corner grounded delta

Discussion in 'Commercial' started by Rather B Riding, May 5, 2017.

  1. Rather B Riding

    Rather B Riding New Member

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    186
    Have you seen this? A 3 phase unit with one leg being a neutral. We have a lot of different power feeds in this town 208/3 phase. 240/ 3 phase. 480/ 3 phase. But I had never seen this till a few years ago.
     
  2. MOFO the psychic gorilla

    MOFO the psychic gorilla sitting on two achers

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  3. Catpower

    Catpower The Crowd Pleaser

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    Yeah there are a lot of old systems still being used, some are real close to insane
     
  4. newtech

    newtech 636

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    Yes, and be careful. What you call a neutral, will light you up.
     
    jrbenny likes this.
  5. 4x4Freak

    4x4Freak New Member

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    I ran into one yesterday on a school with a step down transformer but it was a 240v system. It's the only time I've seen it in this area.
     
  6. jrbenny

    jrbenny Yuge member

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    Not here but over there.
    Yep. Real fun the first time ya see it.
     
  7. MOFO the psychic gorilla

    MOFO the psychic gorilla sitting on two achers

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    1,404
    I though what he said was a neutral is actually a ground....... neutral ground it's kinda the same difference I guess. They call it corner grounded for a reason :p
     
  8. doc havoc

    doc havoc A cunning linguist

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    Is this what is also referred to as two phase?
     
  9. flange

    flange Act like you care and do SOMETHING!!

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    IMT--in my truck
    negative. two phase is its own animal, and comes in three varieties, 3, 4 or 5 wire. its fun the first few times you see it.
     
    Bustawrench likes this.
  10. Rather B Riding

    Rather B Riding New Member

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    186
    They are almost the same but in this case they marked it with white tape. So I referred to it as a
    No only maintenance guys use the term 2 phase.
     
  11. flange

    flange Act like you care and do SOMETHING!!

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  12. crackertech

    crackertech assholiness *

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    Rather B Riding likes this.
  13. crackertech

    crackertech assholiness *

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  14. jamesyarbrough

    jamesyarbrough Amateur Gynecologist

    Messages:
    3,282
    Location:
    Denison TX
    Its not a neutral. Its a bonded leg and it will **** u up. Only one place here has it and thats the fresh water treatment plant. When i went to a unit and found it had 480 to ground on two legs and 0v to ground on the others i tried to condemn the whole damn place. Told them they needed a lineman out now before the whole place burned down. :mrbill:





    A lesson i will never forget.:nono:
     
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  15. jamesyarbrough

    jamesyarbrough Amateur Gynecologist

    Messages:
    3,282
    Location:
    Denison TX

    I read about it. Seems they tried all kinds of things before 3 phase was the standard.
     
    Rather B Riding likes this.
  16. Rather B Riding

    Rather B Riding New Member

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    186
    Technically its a neutral. Only because it is a current carrying wire. That's why they marked it with white phase tape. Found this on a RTU replacement job. The new units were the same phase and voltage so we set the new and hauled off the old till I went wire them up. Had to make a few calls that day. And yes I was told to be very careful with that white wire but I already new that much. Always be careful white the white wires. Three phase buildings use shared neutrals. Just because you shut off the single pole breaker to the circuit you are working on fed from (A) phase the neutral can be carrying current from other circuits on the B and C phases. Its not the voltage its the amperage that kills you.
     
  17. jamesyarbrough

    jamesyarbrough Amateur Gynecologist

    Messages:
    3,282
    Location:
    Denison TX

    The one building i seen with a corner grounded delta system didnt treat the bonded leg like a neutral. They used 3 pole breakers and marked them brown orange and yellow. Like any other high voltage system. But things are different all over the country.

    The nec doesnt call the bonded leg a neutral, it doesn't call the white in a house a neutral either. They are both called " current carrying grounded conductor"..... so yeah i guess in reality its a neutral. Lol

    I used to do commercial electrical. Only thing i ever saw out there were wye systems. We shared every neutral back then to save wire, now the rules are a little different. It wasnt until i got into hvac that i seen deltas.
     
  18. Catpower

    Catpower The Crowd Pleaser

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    Dallas is or was almost all delta wound, I think the power companies owned stock in drill motor companies, they sure didn't last long when you clipped on the wild leg
     
  19. flange

    flange Act like you care and do SOMETHING!!

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    Ha. One of the old buildings I had early in my career used the conduit as the current carrying grounded conductor. As they started to upgrade air handlers the contractors didn't realize and used nonmettalic sealtite whips which caused lots of callbacks.
     
  20. crackertech

    crackertech assholiness *

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    I thought the Delta was bad and sent to the corner to be grounded :D
     
    Rather B Riding likes this.