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Thread: Need clarification

  1. #1
    Join Date
    Apr 2016
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    new york city
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    3

    Need clarification

    Hello. My idiot foreman slash PM has tasked me with installing a hot water heater with a small pump. The heater is 3phase 480. The pump is 1phase 120 that draws nothing. I'm feeding the heater from an empty switch on an MCC board. What I was instructed to do is bring to bring 480 (3# 10's + 20 amp fuses) over to heater and to use one of the 277 legs to feed small step down transformer to feed pump. The problem I face is the primary side of the transformer requires a neutral. There is no neutral to be had in the MCC board it is only 3phase 480. The idiot I work is telling me to ground the neutral on the primary side of transformer. Any thoughts ???

  2. #2
    Join Date
    Feb 2016
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    mi
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    70
    Do it, it's on him. Btw, can you hook 1ph 480 to the tranny?

  3. #3
    Join Date
    Apr 2016
    Location
    new york city
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    3

    Thanx

    Quote Originally Posted by MiElectrician View Post
    Do it, it's on him. Btw, can you hook 1ph 480 to the tranny?
    Its on me also. Boss is POS. I'm not following the term tranny

  4. #4
    Join Date
    Jul 2003
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    I would tell him to get someone else to do it or buy a 480 volt primary transformer (tranny).
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

  5. #5
    Join Date
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    Fl
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    Quote Originally Posted by infinity View Post
    I would tell him to get someone else to do it or buy a 480 volt primary transformer (tranny).
    Ditto

    Roger
    Moderator

  6. #6
    Join Date
    Dec 2007
    Location
    NE Nebraska
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    33,512
    other option is to pull a neutral.

    I wouldn't connect it to the EGC either.

    If the heater is wye connected one thing that will work is to connect the transformer from one line to the wye point of the heater.

    ETA:I take that back, it will work if the heating element were always on, but the pump wouldn't have any voltage whenever the thermostat isn't calling for heat, so it probably doesn't work out for the application.
    Last edited by kwired; 07-17-17 at 10:41 AM.

  7. #7
    Join Date
    Jun 2006
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    Ohio
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    Quote Originally Posted by kwired View Post
    other option is to pull a neutral.

    ....
    He probably would if the MMC had a supply neutral. He said it does not,
    I will have achieved my life's goal if I die with a smile on my face.

  8. #8
    Join Date
    Aug 2004
    Location
    Northern illinois
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    15,657
    sounds to me like his only real option is to get the right transformer.
    Bob

  9. #9
    Join Date
    Jul 2006
    Location
    San Francisco, CA, USA
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    It's harder to find a single phase transformer with a 277V primary than it is to find one with a 480V primary by the way.

    I thought it was illegal to use the EGC as a neutral, because you are making it a CCC?
    __________________________________________________ ____________________________
    Many people are shocked when they discover I am not a good electrician...

  10. #10
    Join Date
    Jan 2009
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    Quote Originally Posted by Jraef View Post
    .

    I thought it was illegal to use the EGC as a neutral, because you are making it a CCC?
    It is.
    "Electricity is really just organized lightning." George Carlin


    Derek

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