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home wiring failure

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by pfile, Jun 1, 2012.

  1. pfile

    pfile Member

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    a couple of days ago my Toyota EVSE stopped working. upon investigation, i found that most of the outlets in my garage were dead, but the breaker for the circuit had not tripped. eventually i figured out that some of the outlets are daisychained from a GFCI outlet, per code. that outlet was extremely well hidden in my garage, but when i found it, it was not tripped either.

    the EVSE was plugged into the outlet immediately downstream from the GFCI.

    figuring the GFCI was bad, i went out and bought a new GFCI. however, when i removed the old one, the "load" wires popped right out of their receptacles. the insulation on the load hot wire was a bit melted and the GFCI itself showed signs of heat damage. it appears that what happened is that under the stress of heating and cooling the load wires simply came loose from the GFCI.

    the house is relatively new (15 years). in theory there should be no problem with drawing 12A continuously from an outlet, and of course i'm only drawing 12A for ~3h per day, if that. at this point i'm assuming that the electricians simply did not tighten down the wires enough on the GFCI and the stress of the EVSE current draw was enough to make the mechanical connection fail.

    anyway, i replaced the GFCI with the new one and tightened everything down as best as possible. also, i've moved the EVSE to the GFCI outlet itself to avoid stressing the output of the GFCI. downstream of the GFCI there was very little load other than the EVSE, so i'm not sure this will really help.

    it might be worth keeping an eye on the circuit you have your EVSE plugged in to, or even inspecting it, to avoid problems like this.
     
  2. fjpod

    fjpod Member

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    It's generally not a good idea to use the push-in type wire connectors on outlets. The amount of contact area is so minimal that even small amounts of electricity can cause things to heat up. It is best to wrap the wire around the screw and screw it down tightly.

    Also, a breaker may be blown but not look like it. Sometimes it helps to turn the breaker on and off once or twice to make sure.
     
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  3. pfile

    pfile Member

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    the breaker was not blown, believe me i toggled the thing several times to no effect. it took me several hours to debug this problem because the GFCI outlet was ridiculously well hidden. during that time i tried everything multiple times :)

    i guess i can go re-do the outlet to get rid of the push-in connection. i believe you when you say the contact could be weak with push-in connections, in theory you should get at least twice the contact by wrapping it around.

    at the time i was working on it i could not be 100% sure that i had turned off the right breaker. the push-in connections were a little safer to do in that circumstance... i did not want to be holding wires with both hands. but now i can test that the circuit is really dead before working on it again.
     
  4. jdcollins5

    jdcollins5 Senior Member

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    Was there a GFCI sticker on this outlet? This is part of the electrical code also that this receptacle be clearly marked on the outlet cover if the receptacle is the first device in the GF string.
     
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  5. pfile

    pfile Member

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    yes, all the outlets that are part of the GFCI daisy chain have stickers on them. the GFCI itself does too, but it's pretty obvious what it is since it looks so different than the other outlets.

    i had a hard time finding the outlet since it was not in a logical place and turned out to be hidden from view by a duct. there are at least 2 more outlets on the same circuit that are not part of the GFCI chain. i think when the house was built, code permitted garage outlets that are on the ceiling or way up high to be non-GFCI. from some googling i did it sounds like the NEC code now requires all garage outlets to be GFCI.
     
  6. If you are working on unknown fixtures, wiring, always identify your HOT lead with a multimeter, or at least keep a nightlight to check outlet.
     
  7. bisco

    bisco cookie crumbler

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    thanks for the heads up p. i guess this is why they recommend a dedicated circuit.
     
  8. JamesBurke

    JamesBurke Senior Member

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    OP's circuit failed to an open state. No reason for the breaker to trip. Just because a breaker works as an on/off switch (maybe just once on install) doesn't mean it will trip under an overload. Really how do we know any of them in our electric panels will work? At least GF 's have test buttons

    Excellent explanation of why pushin spring type connections should not be used. Screw clamped pushins are just fine.
    Receptacles - Wiring Electrical Receptacle Circuits Through A Receptacle - Electrical Outlet Wiring

    "And of course, the method that makes me cringe, back-wiring receptacles, by inserting the wires into the back of the receptacle in holes that sport small tension strips that contact with the stripped wire, making the connection point."
    "The downfall is that the wire can still rotate and is theoretically still a loose connection within the receptacle itself. If the connection tension isn't tight, flickering or arcing can take place and the wires could come out of the receptacle all together. For these reasons, electricians, local electrical codes, and the National Electrical Code often discourage and even disallow such connections."
     
  9. bisco

    bisco cookie crumbler

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    i like wrapping the wire around the old sidescrews. they've been working well for a long long time.
     
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  10. pfile

    pfile Member

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    well what's strange about this is that i *was* using a nightlight (my plug-in prius swag nightlight no less!) and that outlet was dead while the breaker was on, even though apparently the input was still hooked up.

    that's why i had concluded that something had gone wrong with the GFCI itself, since after all the outlets on the GFCI socket are protected as well.
     
  11. pfile

    pfile Member

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    well these are screw-clamped push-ins. i didnt realize that there was any other kind... that seems pretty scary.
     
  12. Not scary, just cheap electrical household outlets that are typical in the US. I used to love working on German plugs when I was over there. They are made very well and twice as expensive. My relatives would cringe everytime they saw me working on anything electrical. They were scared to death of electricity? I think it is ingrained.
     
  13. Rebound

    Rebound Senior Member

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    I have a question about that. It seems that with the standard Leviton outlets I purchase at Home Depot, the push-in connectors do clamp down on the wire when you tighten the screw. I usually loosen the screw, push the wire in, and tighten the screw. Am I incorrect about this?
     
  14. bisco

    bisco cookie crumbler

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    when you loosen the screw, does the wire pull back out?
     
  15. Rebound

    Rebound Senior Member

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    yes. I thought they all worked that way, but I'm just an amateur.
     
  16. KK6PD

    KK6PD _ . _ . / _ _ . _

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    No there are two types of push in sockets. The cheap badly made fire hazard socket that takes 3 seconds to install and saves the electrician what, all of 2.5 more minutes for a proper wrapped around the screw, and in the proper direction mind you, and then torque the screw down nice and tight. Instead they use a socket that has two thin fingers of cheap metal that loosely grabs the wire as it enters the hole, and somewhat grabs it. These little suckers are a fire just waiting to happen.
    The others have two plates that squeeze the wire between them as you tighten the screw down, those are good sockets!
    On a side note, I thought the charger units already had a GFI built into it already. If that is the case you should not daisey chain GFI units. Bad things happen when you do!
     
  17. Jeff N

    Jeff N The answer is 0042

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    Such as what? Multiple gfcis on a single circuit certainly would not be an inherent hazard, right?

    I spent an entire year charging my Volt on a GFCI protected receptical without any problem. It can be a safety advantage of you are using an extension cord because it will help protect against damage caused between the wall socket and the EVSE. For example, kids playing with the extension cord plug, animals biting into the extension cord, etc.
     
  18. KK6PD

    KK6PD _ . _ . / _ _ . _

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    Multiple Non GFCI outlets from one GFI daisey chain socket is OK.
    Multiple sockets on or in separate locations on a single single GFCI breaker is OK.
    Plugging a system that has it's own built in GFCI unit into an GFCI socket or GFCI breaker is WRONG and should never be done!
     
  19. ryogajyc

    ryogajyc Active Member

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    On the contrary, the Owner's Manual pg. 77 explicitly states that that a GFCI outlet should be used:
     
  20. KK6PD

    KK6PD _ . _ . / _ _ . _

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    But does the charger unit have a GCCI ALSO built in, that's the the question and my point, yes or no!