TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker or making a Paypal contribution here: paypal.me/SupportTMC

The GFCI topic

Discussion in 'Technical' started by TEG, Jun 3, 2009.

  1. TEG

    TEG TMC Moderator

    Joined:
    Aug 20, 2006
    Messages:
    17,249
    Location:
    Silicon Valley
    A GFCI (Ground-Fault Circuit Interrupter) is a device inline with a power cord that attempts to detect wiring faults further down the line. If it thinks some of the current is "leaking" then it will disconnect the power. This is meant as a safety system so, for instance, if you were standing in grounded water, and touched one of the energized leads it would try to quickly stop the power flow.

    Sometimes GFCIs can be touchy and trigger in cases when the circuit is basically working but there was a momentary anomaly.

    More information about GFCIs:
    Residual-current device - Wikipedia, the free encyclopedia
    HowStuffWorks "How does a GFCI outlet work?"
    False GFCI Tripping

    Related posts:
    Stefano (stefspec) on Twitter


    The ACP Reductive charging may introduce some leakage and perhaps could trip a more touchy GFCI.

    Thoughts on EV Charging Interfaces
    EV digest 5003
    [EVDL] camping at the charging station - DIY Electric Car Forums
     
  2. TEG

    TEG TMC Moderator

    Joined:
    Aug 20, 2006
    Messages:
    17,249
    Location:
    Silicon Valley
    GFCI as seen on the plug of a Tesla MC120 charge cable:
    [​IMG]
     
  3. TEG

    TEG TMC Moderator

    Joined:
    Aug 20, 2006
    Messages:
    17,249
    Location:
    Silicon Valley
    GFCI as it relates to 240V EV charging discussion here:
    [/FONT]
     
  4. TEG

    TEG TMC Moderator

    Joined:
    Aug 20, 2006
    Messages:
    17,249
    Location:
    Silicon Valley
    #4 TEG, Jun 4, 2009
    Last edited: Jun 4, 2009
    It seems one reason why some think a GFCI is required is because of NEC 625-22:
    About the NEC

    NEC 625 isn't followed everywhere, so including GFCI may be just to satisfy certain locations / jurisdictions.

    Apparently the mobile charge kit Martin made for himself doesn't include GFCI.

    Is it time to revise the NEC based on what has been happening to Tesla with their GFCI problems?
     
  5. TEG

    TEG TMC Moderator

    Joined:
    Aug 20, 2006
    Messages:
    17,249
    Location:
    Silicon Valley
    From PG&E EV CHARGING ESSENTIALS:
    So that sounds like the NEC was already revised to say you could use something else (but what?) instead of GFCI.
     
  6. TEG

    TEG TMC Moderator

    Joined:
    Aug 20, 2006
    Messages:
    17,249
    Location:
    Silicon Valley
    #6 TEG, Jun 4, 2009
    Last edited: Jun 4, 2009
    Las Vegas Electric Vehicle Association - May 2009 Newsletter

    http://www.electricity-tool.com/doc/36373-ES8/

     
  7. TEG

    TEG TMC Moderator

    Joined:
    Aug 20, 2006
    Messages:
    17,249
    Location:
    Silicon Valley
    California Uniform Building Code As It Relates to Electric Vehicles
     
  8. Tdave

    Tdave Member

    Joined:
    May 16, 2008
    Messages:
    721
    Location:
    Columbia, MD
    What's this talk of a required 40A-240V GFCI? Does such a beast exist? Word from Tesla as to why the 240V connector is only 30A right now is because there is no 40A-240V GFCI on the market for them to incorporate into it.
     
  9. TEG

    TEG TMC Moderator

    Joined:
    Aug 20, 2006
    Messages:
    17,249
    Location:
    Silicon Valley
    EVDL Archive / Forum Interface - Electric Vehicle Discussion List
     
  10. TEG

    TEG TMC Moderator

    Joined:
    Aug 20, 2006
    Messages:
    17,249
    Location:
    Silicon Valley
  11. vfx

    vfx Well-Known Member

    Joined:
    Aug 18, 2006
    Messages:
    14,792
    Location:
    CA CA
    I told SP about the double GFI Roadster trip problem when Doug posted the info on his Milbank installs. About that time Tesla announced the "fix".
     
  12. TEG

    TEG TMC Moderator

    Joined:
    Aug 20, 2006
    Messages:
    17,249
    Location:
    Silicon Valley
    Did the fix work?
     
  13. vfx

    vfx Well-Known Member

    Joined:
    Aug 18, 2006
    Messages:
    14,792
    Location:
    CA CA
    Apparently not all who have had the firmware upgrade have had a resolution. Many have replaced the GFCI plug on the MC120 with a standard plug. Don't know if the MC240 has any GFCI issues.
     
  14. vfx

    vfx Well-Known Member

    Joined:
    Aug 18, 2006
    Messages:
    14,792
    Location:
    CA CA
    In the home GCFIs are required outdoors and in rooms like kitchen and bath. I was told yesterday that bedrooms are next (very soon) and you might as well just do the whole house if you are building new.

    Could this be another tiny time bomb issue for charging future EVs?
     
  15. TEG

    TEG TMC Moderator

    Joined:
    Aug 20, 2006
    Messages:
    17,249
    Location:
    Silicon Valley
    I don't know if this info is correct, but here is a site that claims "experts" say that two GFCIs are more dangerous than one:
    2007 HOT SPRINGS SAFETY SEMINAR - Tips from industry experts


    Questioning the accuracy of the above... For one, I think many GFCIs are 5ma, not 30ma. For another, I am not sure I believe that two in series doubles the ma rating before trip. I would think it would be the lower of the two, but supposedly the above site was advice from an expert.

    ---
    I spoke with someone who was frustrated that the MC120 had a GFCI because they said that the code required that the outdoor outlet, not the plug have the GFCI so there would be many cases where the outlet already had GFCI. Perhaps there should be two versions of the MC120 - the existing one for indoor / garage use where there is no GFCI on the socket, and another for outdoor use (which doesn't include a GFCI) that expects the outlet to already have the GFCI?

    Apparently the firmware change ramps up the current draw more slowly to avoid tripping one (or more) GFCIs in the circuit.
     
  16. vfx

    vfx Well-Known Member

    Joined:
    Aug 18, 2006
    Messages:
    14,792
    Location:
    CA CA
    What if they only made the non GFCI and included one of these:
    Prime Wire & Cable Portable GFCI Adapter and Surge Protector, Model# GFP10000 | Switches + Fuses | Northern Tool + Equipment

    http://www.tycothermal.com/assets/Americas/English/Document/Datasheets/1632/H55402_H931_DS_032006.pdf

    Tower Shock Buster Portable GFCI
     
  17. TEG

    TEG TMC Moderator

    Joined:
    Aug 20, 2006
    Messages:
    17,249
    Location:
    Silicon Valley
    Yep, that might of worked... I guess they didn't want to take the risk that someone would forget to install the add-on GFCI when there wasn't already one behind the socket.

    By the way, more GFCI fun:
    Two GFCIs in series - OK or not? [Archive] - Straight Dope Message Board
     
  18. W.Petefish

    W.Petefish Active Member

    Joined:
    Apr 29, 2011
    Messages:
    1,059
    Location:
    North Texas (DFW)
    Has anyone, other than me, had their HPC's GFCI trip?
     
  19. bonnie

    bonnie Oil is for sissies.

    Joined:
    Feb 6, 2011
    Messages:
    14,241
    Location:
    Columbia River Gorge

    I bought one of those and threw it in my bag when I removed the GFCI from my cable assembly. Had Tesla done that to begin with, it would have saved me from much charging frustration on a roadtrip.
     

Share This Page