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3 prong AC for main cabin

Discussion in 'Gen 5 Prius Main Forum' started by Will B, Aug 22, 2023.

  1. ChapmanF

    ChapmanF Senior Member

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    There might not be a GFCI.
     
  2. sam spade 2

    sam spade 2 Senior Member

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    I was going to post something similar......but you said it better.

    IF a ground fault should occur in the AC powered equipment, the stray voltage would then also be connected
    to the chassis of the CAR. NOT A GOOD SITUATION.

    I feel kind of guilty pointing this out.......because now he likely will feel uneasy about the situation again.
     
  3. bumblebee_prime

    bumblebee_prime New Member

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    I might be crazy but I just plugged mine into the back port, it has three prongs and the cable is more than long enough to reach the front seats
     
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  4. Tom_06

    Tom_06 Active Member

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    I have an old Statpower 12V to 120 AC inverter that I used to use from the early 1990's to charge my laptop while I was traveling (gave it up when I switched to using an iPad in 2010). Like yours, the ground of the 3 prong outlet is connected straight through to the chassis ground of the 12 V input plug.

    Using a mains tester, I get all three lights on, which is not listed as a known condition. I don't think yours is showing open ground in the photo if all three lights are on. Definitely neither of us is getting a circuit OK result.

    I then used a fluke multimeter to measure AC voltages on the inverter. Hot to ground and neutral to ground both gave about 76 volts A/C and measured 115 Volts between hot to neutral.

    As I am still waiting for my ordered 2023 Prime, I can't check the outlet on that car. I would suggest if the mains tester gives the same result as your old inverter and/or the 3 prong outlet in the hatch as you get with your 3-to-2 prong adaptor with your added ground wire, then you have the equivalence with what you had using the old inverter.
     
  5. Trollbait

    Trollbait It's a D&D thing

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    I second this KISS solution.
     
  6. Will B

    Will B Active Member

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    Tom_06: All three lights on is really weird, but that may correlate to what you measured with the Fluke. 120VAC clearly between hot and neutral but then for some reason each floating to their midpoints around ground. For those testers to light, there has to be enough current flowing from hot and neutral to ground to actually light the neon bulb, so that is more than "the tinglies" class current, so yea, that seems pretty spooky.

    Again, I still mostly agree with Sam and others, the danger is very low. The whole purpose of ground and GFCI is redundancy. Ground is there if you have a failure where hot somehow touches the chassis. GFCI is there in case hot touches the chassis *AND* for some reason the chassis ground failed (or your double-insulation fails). Neither of those envision what is in the car which has neutral floating relative to ground. Having said all that, with 120V at 1500W being available, I kinda like the idea of a lot of redundancy.

    Trollbait and Bumblebee: Yea, just plugging into the back is by far the easiest approach and electrically what I want. But, this is my new Prius and draping extension cords over back seat passengers (which I will have for an upcoming road trip) seems a bit clunky. The cheater-adapter ain't exactly pretty, but seems arbitrarily a bit less ugly. I just really wish Toyota just had a 3-prong plug in the center console!

    Thanks to all for the feedback. This is nuanced stuff where there are going to be different opinions. It's nice to be in a forum where we discuss them politely!!!

    will
     
  7. Tom_06

    Tom_06 Active Member

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    I expect your solution with the cheater-adaptor will give you exactly the same situation as the hatch area 3 prong outlet. Try the mains tester on both to give an indication of this.
     
  8. Will B

    Will B Active Member

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    Tom_06: Yep, 99% sure it would be the case and it was, same lights for the center console with my ground adapter. The way the manual reads, the two outlets are just wired in parallel. There's even chassis ground less than two inches away from the outlet with the USB connectors.

    As accurately predicted by others I'm over-cautious and looking at an inline GFCI breaker. They are not terribly expensive. I've also asked my buddy who is a Rivian owner to check out his outlets and see how they are wired. Despite the pages and pages of warnings, Toyota isn't doing anything bad. Lots of things would have to go wrong before GFCI or even ground would matter.

    will
     
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  9. ken2023

    ken2023 Junior Member

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    Noticed the lack of a ground pin as well. With your adapter it might have a few purposes: 1) ensure the prongs are inserted in the correct orientation wrt hot and neutral, the same reason some two-prongs have a fat and narrow side; 2) connects to shielding that prevents electromagnetic interference; 3) reduce electrocution risk from any exposed metal parts, probably not relevant if your adapter is all plastic.
     
  10. Trollbait

    Trollbait It's a D&D thing

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    The rear seat bottom of my gen2 popped right off, and people were pulling that part off the gen4 at press events to look at the battery. Temporary routing a cord to the back and out of the way may be easy.
     
  11. Will B

    Will B Active Member

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    Trollbait: Interesting point! Hopefully within the next month or so I will be installing my 2-meter ham radio in the car so will be running wires around the interior for that. I could do something with the AC at the same time. Kinda like that as an option!

    will
     
  12. ColoradoCrow

    ColoradoCrow Active Member

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    Sometimes....the tingle makes me feel better.....:oops:
     
  13. Will B

    Will B Active Member

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    Just a follow-up, my buddy with a Rivian finally tested his truck. Same wiring, hot and neutral both floating relative to ground with ground tied to the chassis.

    will
     
  14. Blizzard_Persona

    Blizzard_Persona Senior Member

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    So what could you potentially plug into the front and rear AC plugs and run safely? Just trying to get an idea of what these plugs can safely be used for?
     
  15. sam spade 2

    sam spade 2 Senior Member

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    I think this has already been said a couple of different ways but................
    You should be able to use ANY UL approved device that doesn't exceed
    the current capacity and not have to worry about safety.

    Plug it onto which ever outlet matches the power cord.
    A 2 conductor power cord should be fine in either type of outlet.

    This assumes that you are not using some home-made device
    and are not doing something really stupid.
     
  16. Will B

    Will B Active Member

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    Yep, fully concur! My main (and original) gripe was only a two-prong outlet in the center console. The GFCI thing was a bit of a rabbit hole just since it was a surprise to me. I have my ground adapter which is just because my wife's laptop supply is 3-prong and I prefer not to run a cord all the way to the back.

    will
     
  17. Blizzard_Persona

    Blizzard_Persona Senior Member

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    I guess wording my question a slightly different way might make more sense. What appliances / devices have current owners with the AC plug actually plugged into them?

    What were the max wattages for each plug again?

    I hear mention of using the prime as a small home generator, but what can actually get plugged in without blowing the fuses?
     
  18. Will B

    Will B Active Member

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    Blizzard_Person: The inverter is rated for 1500W and besides a few warnings about not liking highly inductive loads with excessive startup surge current, not a lot of caveats. While not explicitly said, from the description there is a single 1500W inverter that is just wired in parallel to both outlets. They are clear that it is 1500W total from either outlet or both combined. The idea of being a portable generator seems pretty cool, but for me it is just powering things like laptops and such while on road trips.

    will
     
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  19. Will B

    Will B Active Member

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    All, OK, one more interesting follow-up on GFCI. I did go ahead and purchase an inline GFCI breaker. THE GFCI TESTER DIDN'T TRIP THE BREAKER!! Just to confirm, I tested the breaker and my GFCI tester on a regular household outlet and it worked as expected, so nothing to do with bad equipment.

    I thought the whole purpose of GFCI is to detect a small delta in current between live and neutral and if detected, trip the breaker. The GFCI tester allows some current from Live to go to Ground which should trip the breaker. When I used the GFCI tester on the car directly and pressed the button I saw the Hot/Neutral swapped light illuminate, so some current was going to ground I thought. If the GFCI breaker isn't tripping that says it isn't detecting any difference in current.

    Just to add to the confusion, pressing the test button on the GFCI breaker itself DOES work, it trips the breaker. Why not my tester? The built-in test and my external tester should be doing exactly the same thing.

    Yes, this is a rabbit trail, but this is something I want to understand why what I am seeing is happening. This is getting weirder.

    will