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Extra wire on MC240 GFCI

Discussion in 'Roadster: Technical' started by btown, Oct 27, 2011.

  1. btown

    btown Member

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    Does anyone know what the extra (light gauge red) wire on the the MC240's GFCI is for? I'm sort of assuming it's some sort of remote control line, but I can't find any information on it. It connects to the pilot board.
     
  2. dwegmull

    dwegmull 2013 Model S 85

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    I guess you've opened yours. I have yet to see the inside of one of those. Could you post some pictures? It may help getting you some answers.

    That being said, let's speculate!

    High power GFCI do not have built-in contactors (unlike the 120V GFCI outlets commonly used in houses). Maybe this is the control signal that energizes a contactor located on the main board. I'm currently building my own EVSE as a learning exercise. Its overall design is very similar to the MC240: compact and portable. In the design phase, I quickly came to the conclusion that by using a secondary small relay located along the GFCI sensor control wire on its way to the main contactor, I only needed one contactor. The relay is controlled by the J1772 state machine, running in a micro-controller.
    A further refinement would be to replace the off the shelf GFCI sensor by a coil and an amplifier, feeding its signal into the micro-controller. This would save the need for a second relay and significantly reduce the size of the EVSE...
     
  3. btown

    btown Member

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    I've done a lot more than just open mine..... I hijacked the Tesla cable/connector to create a J1772 adapter, hijacked the pilot circuit to make my Spare Mobile Connector operate at 240V and all that is left is the GFCI. I have a use for that as well, but I need to understand what the extra low current red wire is for.

    Here's a link to the specs and what it looks like. The model number is PGFS-23105-184, but the specs don't show any application data.

    PGFS-23105 datasheet, Pinout ,application circuits 30 Amp Permanent Series (Splice-In) GFCI/ELCI
     
  4. TEG

    TEG TMC Moderator

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  5. btown

    btown Member

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    Found an ever better link from North Shore Safety's site:

    http://www.nssltd.com/pdf/30%20Amp%20Perm.pdf

    According to their table, this particular model does not have fault output notification. Yet the red wire definitely was connected to the pilot board. It doesn't really matter at this point because I think I've determined that the extra wire is for fault notification. I was sort of hoping it was some sort of external trip line which would have been useful for me to use it as a sort of 240V relay.
     
  6. btown

    btown Member

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  7. TEG

    TEG TMC Moderator

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    I think I beat you to finding / posting that link...
    But from the way I read it, it does have the output.
    It shows "1" in the column labeled "ANNUN", right?
     
  8. TEG

    TEG TMC Moderator

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    Check the timestamp... I beat you by 6 whole minutes!
     
  9. VolkerP

    VolkerP EU Model S P-37

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    It is very rare for someone beating TEG on posting information in this forum that you find only by hard & deep research...
    Special celebrations were held at that occasions.
     
  10. GSP

    GSP Member

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    TEG, you are the greatest. But, the truly great do not need to brag. :)

    GSP
     
  11. rabar10

    rabar10 FFE until Model 3

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    So how are you planning to use the GFCI? EV-related or separate application?
     
  12. btown

    btown Member

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    Yep. I bet we were looking at it at the same time, but I just typed more and therefore took 6 minutes longer to post. :biggrin:
     
  13. btown

    btown Member

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    I don't see a "1" in the annun column for the "23105" row. Are you sure you're looking at the right row?
     
  14. btown

    btown Member

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    I was hoping maybe it was a control line which would allow me to use the GFCI as a safety relay for my 120V to 240V combiner.
     
  15. TEG

    TEG TMC Moderator

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    I think I was looking at 23015... :redface:
     
  16. TEG

    TEG TMC Moderator

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    Does it look just like this? :
    PGFS-23105.JPG
     
  17. TEG

    TEG TMC Moderator

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  18. scott451

    scott451 KWH-PWR#1349Sprt,S Sig#96

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    IIRC. The extra red wire is a 240v control for the contactor inside the gfi. The pilot board uses this signal to turn on/off the 240v to the car.
     
  19. btown

    btown Member

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    That's what I was hoping it might be for, but I see nothing in the spec sheet regarding it. Do you know what sort of control stimulus you apply to this line in order to call for the contact closure? If I remember right (I don't have the gfci in front of me right now) the unit has 2 line inputs and 2 line outputs. So I would sort of presume that the only natural thing to expect would be that applying ground to the red control might close the relay? That would be a pretty simple way for the device to work, as it would just require a 120V relay coil inside.

    Do you know Scott?
     
  20. btown

    btown Member

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    Yes it looks like that EXCEPT there is a 5th red wire, which is lighter gauge then the rest.
     

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