extension cord specs

Discussion in 'Prime Plug-in Charging' started by Pizza Driver, Dec 18, 2016.

  1. Pizza Driver

    Pizza Driver Active Member

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    I saw it mentioned in another thread that it was ok to use an extension cord if it had the proper specs. What are those specs, how can I tell if an extension cord has those specs (is there something attached to the cord when you buy it that says?), and where might one find such a cord (I am assuming something like Lowes/Home Depot would have one, but also, perhaps Walmart?)?
     
  2. priuscatprimeguy

    priuscatprimeguy Senior Member

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    the cord would have to be able to carry at least 15 amps of current

     
  3. jdenenberg

    jdenenberg EE Professor

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    You can easily look up the requirements. See:

    UL General-Use Circuit Ampacity Reference Chart


    14 gauge is marginal for a 15 amp load. 12 gauge would be fine.

    I have a 6 gauge cable for my 30 amp 220 volt generator which is overkill. Most people use 10 gauge, I asked for 8 gauge, but the vendor only had 6 gauge so that is what I use.

    JeffD
     
  4. alex j

    alex j New Member

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    Cable that is ratet at 16 amp is what you need. I used Colman cable 03537 12/3 9-footer. If you need longer than that you can use 2 of them which will get you 18 feet. You can buy them any hardware store like Home depot or even from Amazon.

    Posted via the PriusChat mobile app.
     
  5. Lee Jay

    Lee Jay Senior Member

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    Don't do that. If you need longer, get a longer one. The connectors are the lowest reliability and highest resistance part of the system.

    The right specs in this case (Prime with stock cord) is 12AWG (12/3) either plugged into a GFCI outlet or outlet protected by GFCI or a cord with a GFCI built in. Any length up to 100 feet is probably fine (some will tell you 25 feet is max but that isn't so except in certain special cases). In fact, if you only need a short one even a 14AWG (14/3) is fine. I can't give you a specific length because it depends on a number of other factors.
     
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  6. alex j

    alex j New Member

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    Good technical advice. On the other hand, MTBF of a connector is longer than the life of a car. There are hundreds of connectors in automobiles.

    Posted via the PriusChat mobile app.
     
  7. Lee Jay

    Lee Jay Senior Member

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    The blade connectors in standard outlet are really lousy by modern standards. They tend to work okay because most high current applications don't see them connected and disconnected (cycled) all that often or used for all that long. However, an 18 foot cord will be way more reliable than two 9s ganged together especially in a high current, high duration and likely dirty environment.
     
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  8. PT Guy

    PT Guy Active Member

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    Almost every store that sells to contractors will have 12/3 extension cords--Lowe's, Home Depot, my local hardware store & local lumber yard, many others. Be careful of the wording on the package. "Heavy duty" is on the wrapper for 14 gauge, and I'd consider #14 to be medium duty at best. You'll see 12/3 on the label and imprinted in fine print on the cord itself every few inches. As noted above, buy the one that is closest to the length you need. The cheapest might have cheapo plug and connector; get a good cord. (A connector is the portable equivalent of a receptacle.) If the plug doesn't fit tightly into the receptacle, don't use that receptacle. Change it. The usual 69ยข 15 amp receptacles work pretty good until they don't. A much better 20 amp receptacle costs all of $3. You'll spot these; one slot looks like a sideways T.

    My feeling is that Toyota proscribes extension cords because somebody would use very light duty lamp cord, maybe snip the ground pin off the plug, and file a warranty claim when something expensive burned up. Or file a law suit when their house burned up.

    12/3 means...12 AWG (American Wire Gauge) wire is 0.0808" in diameter. 3 means that the cable contains 3 conductors...3 separate wires. 14 AWG is 0.0641" in diameter. The bigger the wire, the more amperage it can carry without exceeding the temperature limits.

    Amperage is the rate of flow of the electrons that comprise the electricity. Kind'a like gallons per minute out of a water hose.
    Voltage is the force of the electricity. Kind'a like pressure in that water hose.
    Watts are the unit of power. Kilowatt = 1000 watts. Volts x amps = watts*
    Kilowatt-hours is the unit of measure of electrical power; 1 kw-hr = 1000 watts for one hour. My home electric bill is billed per kilowatt-hour.

    *Neglecting the power factor of AC circuits for this discussion, and not even getting close to polyphase.
     
    #8 PT Guy, Dec 20, 2016
    Last edited: Dec 20, 2016
  9. Trollbait

    Trollbait It's a D&D thing

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    DO NOT install a 20 amp receptacle on a 15 amp circuit.
     
  10. plow

    plow Junior Member

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    I'm going with this and this.

    12/3 25 ft extension cord

    and

    12/3 Defiant GFI

    [​IMG] [​IMG]
     
    #10 plow, Dec 20, 2016
    Last edited: Dec 20, 2016
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  11. trescenzi

    trescenzi Junior Member

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    Seems like I'm a little late to the party but for posterity I wanted to link cords I've used with success.

    This is the cord(15' 12/3) I use when traveling to give me a little extra reach. It fits along with the Toyota charging cable into the little slot in the back of the car which is very nice. Sometimes it's not long enough but I'd rather have a shorter cord with a known low voltage drop, <1V, for plugging into unknown outlets. The power loss is going to be negligible and it should be very safe. A similar 25' cord should also be about as safe and have a drop of around 1V.

    This is the cord(100' 12/3 all weather) I use at home to reach my parking space. It's very long and has a much higher voltage drop of about 5V. This means the power loss is nearing 60W. At that rate I'd be worried about using it with unknown outlets however I can say that it's worked great for me these past 3 weeks even when covered by a foot of snow. The power loss will cost more money, about a third a kWh is lost per charge, but it's still small enough of a loss to not really increase charge times by an appreciable amount or be really unsafe.

    Just a little disclaimer that Toyota doesn't condone the use of cords and it explicitly states not to use them in the manual so do be careful and do your research on cords. It's worth paying a bit more for a higher gauge cord when you're powering something like a car. I've found that this calculator gets very close to the numbers I've measured with a kill-a-watt.
     
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  12. TJG1955

    TJG1955 New Member

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    An extension cable works regardless (provided it's the correct type) of what the Toyota manual says?? This is something I was considering since I live in a townhouse without a garage. My parking space is directly in front of my front door so an extension cable isn't a problem. Regarding condo rules - to me it's no different than running a hose across the sidewalk while washing a car. I was going to put two of those small safety markers out or get a cord cover so people don't trip.
     
    #12 TJG1955, Jan 26, 2017
    Last edited: Jan 26, 2017
  13. bisco

    bisco cookie crumbler

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    of course. the manual is simply a legal disclaimer. if they said it was okay, people would burn their houses down and sue toyota.

    as long as you use the correct cord size, there isn't a vandalism problem, and no one trips, you'll be fine.
     
  14. Rmay635703

    Rmay635703 Senior Member

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    MTBF on a 20 amp outlet is 3x a 15 amp one, a fire is possible on a worn 15 amp breaker.

    The risk of a20 amp on a 15 amp breaker is low since a blown breaker is well irrelevant and 15 amp breakers are very rare.

    Besides not meeting code during sale minimal risk and the 20 amp breaker is less likely to light on fire.

    Add to this over 90% of homes have only 20amp + breakers but the load is shared over a string of receptacles.

    If you have a house that is old enough to have 15 amp wiring it's more likely you have 10 amp pre war wiring and you have bigger problems than the outlet.

    If your house is old enough to have 15 amp breakers throughout, best to have a new wire ran to your garage and maybe even a new panel, get that old ball and knob crap out of your house.

    My father is an electrician
     
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  15. bisco

    bisco cookie crumbler

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    really? that's amazing. everything around here is 15 amp, except kitchen/bath.
     
  16. Rmay635703

    Rmay635703 Senior Member

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    Age, Duplex, apartment or mobile home?

    Everything out this way is either 10 amp (lights only) or 20 amp.
    My folks have a 30 amp 10 gage that goes to all 3 bedrooms.

    I would be pissed if I had 14 gage wire everywhere in my home.

    15 amp circuits unless "dedicated"
    Really aren't safe to use for charging above 8 amps because someone may throw on a light or something else on that breaker.
     
  17. bisco

    bisco cookie crumbler

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    must be geo, we don't have any 10 amp, no matter the age. i'm not up on new construction, but 8 years ago, it was all 15 except power hog area's.
     
  18. Rmay635703

    Rmay635703 Senior Member

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    Hmm, I haven't stepped foot in a sub 30 year old home.

    You should check what gage wire they used on each branch, if it's 12 gage you could legally use a 20 amp breaker on it and just match up the receptacles.

    14 gage wire in home wiring should be banned, its too small for a modern home.
     
  19. bisco

    bisco cookie crumbler

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    it's 14 on the 15 and 12 on the 20. i have never seen problem with 14 for living/dining/bedroom's etc.
     
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  20. jdenenberg

    jdenenberg EE Professor

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    My home was built in 1978 so it has many 15 amp breakers and a lot of 14 gauge wiring. I upgraded the distribution panel to modern arc fault and ground fault breakers last year.

    JeffD
     
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