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Need a crash course on 100 amp US shorepower

Discussion in 'Technical Discussion' started by Pascal, Sep 10, 2021.

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  1. Capt Ralph, Sep 11, 2021
    #21
    Capt Ralph

    Capt Ralph Senior Member

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    I am calling 408Vac at your slip un-usual also. Anybody tested with a volt meter yet?
  2. Capt Ralph, Sep 11, 2021
    #22
    Capt Ralph

    Capt Ralph Senior Member

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    Narrow and specialty use market. Are you going to plug your boat into a container power grid?
    Not sure if container service was in mind when the slip was updated.

    For boat service, neutral is at the dock.
    Pending the boats transformers on board, neutral may be artificially inserted at these transformers output.
    Last edited: Sep 11, 2021
  3. Capt Ralph, Sep 11, 2021
    #23
    Capt Ralph

    Capt Ralph Senior Member

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    The usual for most rebuilt and new marinas I have witnessed. Y transformers, 115/208Vac single phase.
    Rebuilt and new service may also include GFI-GFCI type service breakers.

    It is going to get harder and harder in the future to avoid these services.
  4. Slimshady, Sep 11, 2021
    #24
    Slimshady

    Slimshady Senior Member

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    No of course not but they are nema standard plugs.
  5. Slimshady, Sep 11, 2021
    #25
    Slimshady

    Slimshady Senior Member

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    I've never seen 208v single phase it's always 3 phase
  6. Capt Ralph, Sep 11, 2021
    #26
    Capt Ralph

    Capt Ralph Senior Member

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    208Vac single phase uses 1 of the 3 (3 phase) leads.
    3 phase uses all 3 of the 208Vac leads.
  7. Pascal, Sep 11, 2021
    #27
    Pascal

    Pascal Senior Member

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    To clarify:

    the boat has isolation transformer in the Atlas system and does not bring Neutral on board. Same with the 84 which had a Charles isolation transformer. The neutral was not connected. Actually 100amp shore power cable can be bought with or without neutral.

    I checked the voltage on that 4 pin outlet. Getting 470+ between either of the 3 hots and 260 between the G (smaller pin, at 7 o clock) and each of the hots

    what I still don’t understand is what the other 2 adapters I found on the boat are for (pictures in first post), they are different from everything

    2FF77758-86F1-41D6-8A14-9DD05B8DE2C2.jpeg
  8. Slimshady, Sep 11, 2021
    #28
    Slimshady

    Slimshady Senior Member

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    Good news is you have 480v 3 phase which is plenty of power.
  9. Pascal, Sep 11, 2021
    #29
    Pascal

    Pascal Senior Member

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    I never mentioned 408vac.
  10. Slimshady, Sep 11, 2021
    #30
    Slimshady

    Slimshady Senior Member

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    Sorry not trying to be a jerk. 115/ 208 is 3 phase. Each of the 3 hot lines are 115 volt each measured from line to ground and 208volts across any 2 hot lines.
    MBevins likes this.
  11. Capt Ralph, Sep 11, 2021
    #31
    Capt Ralph

    Capt Ralph Senior Member

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    Back to theory;
    Single phase in normally in a pretty sine-sinus signal, peak to peak cycle, 180 degrees apart.
    Now, split that nice pretty signal 3 ways thru a Y transformer. The 3 new peaks are 120 degrees apart. Measured peak to peak, each leg is now 208Vac.
    Each leg is still in its own single phase, just not as pretty as before.

    Input to these transformers may be 480 or taller in Vac.

    https://electricalacademia.com/electric-power/three-phase-system-explained-star-delta-connection/
    Last edited: Sep 11, 2021
  12. Capt Ralph, Sep 11, 2021
    #32
    Capt Ralph

    Capt Ralph Senior Member

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    OOppps, I meant 480Vac.
  13. Capt Ralph, Sep 11, 2021
    #33
    Capt Ralph

    Capt Ralph Senior Member

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    Incorrect. It is one of the three phases.
    Output from a Y or Star transformer that generates or passes 3 phase service.

    Correct. Each line is a phase, 120 Degrees out of cycle from the other, Hence - 3 phase.
    Last edited: Sep 11, 2021
  14. Pascal, Sep 11, 2021
    #34
    Pascal

    Pascal Senior Member

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    As I said earlier I tested the outlet and it is 480VAC 3 phase which the atlas system can accept. As evidence by the thread title I m no expert on 100amp power and high voltage but I m learning
  15. Slimshady, Sep 11, 2021
    #35
    Slimshady

    Slimshady Senior Member

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    I'm an engineer, I understand 3 phase power. 115/208 is 3 phase electrical. 115v is only one line of 3 . 208 is all three. That's why it's 115/208 and not just 115.
  16. Capt Ralph, Sep 11, 2021
    #36
    Capt Ralph

    Capt Ralph Senior Member

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    The dock outlet has 4 pins and 480Vac?
    What pins made 480V?
  17. Capt Ralph, Sep 11, 2021
    #37
    Capt Ralph

    Capt Ralph Senior Member

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    Then what is 115/230V ?
    115/208 is a part or component of 3 phase electrical. It is a single wave form of 3.

    You state it here your self but still argue some point?

    https://electricalacademia.com/electric-power/three-phase-system-explained-star-delta-connection/
  18. Slimshady, Sep 11, 2021
    #38
    Slimshady

    Slimshady Senior Member

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    I already explained it not doing it again
  19. Capt Ralph, Sep 11, 2021
    #39
    Capt Ralph

    Capt Ralph Senior Member

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    Good day then.
  20. Pascal, Sep 11, 2021
    #40
    Pascal

    Pascal Senior Member

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    Thank you got the replies. Yes indeed. I m now starting to understand this better and as mentioned the table found at the back of the Atlas manual now makes sense.
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