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Wall charger + 240v extension cord to outlet. Bad idea?

Discussion in 'Prime Plug-in Charging' started by 0pt1mu3_pr1m3_2021, Nov 6, 2021.

  1. 0pt1mu3_pr1m3_2021

    0pt1mu3_pr1m3_2021 New Member

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    I just bought my Prius Prime 2021 this past July and love the car! I do mostly short errands around the city and always charge the car after each trip, to ensure I have the full 30+ mile range.

    My dilemma is I have a detached car garage with no power. From the back of my house to the detached garage I need about 50 feet of wire. Currently, I hang a 25 feet extension cord (10gage) from my back window, then hook it up to the Toyota charger and it's enough reach for me to plug it into the Prime.

    I was thinking of getting a wall charger, something like Grizle or Chargepoint Flex. A bit a future proofing with 40amp charger. I was considering having electrician put a 240v outdoor outlet in the back of the house. I would then have 3 options:

    (1) put 240v outdoor at the back of the house, plug wall charging station at the back of the house, then run J1772 extension to the car;

    (2) put wall charging station at the garage, then run 240 volt extension from back of the house to the wall charging station at the garage; or

    (3) no wall charging station anywhere, run 240 volt extension from back of the house to portable 40amp charger, to car.

    Of these three options, I would would like to do 2. Do you guys have any thoughts on these 3 options I am considering ? Are options 1 and 2 horrible ideas and I should just do 3 ?
     
    #1 0pt1mu3_pr1m3_2021, Nov 6, 2021
    Last edited: Nov 6, 2021
  2. bisco

    bisco cookie crumbler

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    what am i missing on option 1? if the j1772 will reach the car from the back of the house, what's the problem?
    the only thing with a 240v extension cord would be making sure it is equipped to handle the job, and weather proof.
    sometimes, the connections are the weak points.
     
  3. 0pt1mu3_pr1m3_2021

    0pt1mu3_pr1m3_2021 New Member

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    I was thinking it's nice to have the wall charging station literally next to the garage by the car. It's not a big deal though if the wall charging station is at the back of the house and I run a J1772 extension. It seems like that's the safer bet. From the articles I am seeing people are saying J1772 extensions are safer than running 240volt extension cords.
     
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  4. MalachyNG

    MalachyNG Active Member

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    If you're hiring someone to install a 240v outlet it shouldn't be much more to just run the line to your garage. If he wants to charge you to dig a shallow trench to the garage you could probably dig that yourself. Just call 811 to have utilities flagged before you start digging around by your house. Maybe even get a quote for adding a sub box for your garage if you think you might want to add a door opener or outlets in the future.
     
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  5. dig4dirt

    dig4dirt MoonGlow

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    ditto @MalachyNG

    It will cost a bit to install electric to your garage, but small price to pay to future proof it.

    DIY as much as you can to save on costs.
     
  6. BiomedO1

    BiomedO1 Senior Member

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    ditto @MalachyNG

    Older homes electrical box setup usually don't have the capacity to handle an additional 40 amps. Sub-panel it out and make a run to the garage. If you decide later to turn the garage into a man-cave or workshop, the power will be there to do so.

    IMHO: Extension cords are inherently dangerous when used as a primary fixture and illegal in most jurisdictions, but it's your backyard. If there are any exposed wires or connections laying in a puddle of water - that puddle may be energized.
     
  7. bisco

    bisco cookie crumbler

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    around here, it's an 18" deep trench with wiring inside pvc sleeving, and proper backfill. not cheap, and depends on future needs vs costs.
     
  8. jerrymildred

    jerrymildred Senior Member

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    Another ditto for @MalachyNG. As an electrician, I would strongly recommend against an extension cord for frequent, long term use. The connections gradually get looser and looser and will eventually get hot enough to cause problems. And then, too, there's the step of making them weather-proof. It can be done, but it'll get tiresome.

    If your house wiring is adequate, it's not a big deal to bury some conduit and run wires to the garage and put in a small sub panel. In fact, because my breaker box was full, I had to put in a sub panel for my 240V outlet. The wire will be the most expensive part besides what you pay an electrician. But, aside from the electrician, you might not spend much more on the installation than you might on a good quality extension cable. And you'll be much happier with the results.
     
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  9. Salamander_King

    Salamander_King Senior Member

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    I am in a similar situation. Although I have a wire going to our detached garage ~50' from the house, it is on a 20A circuit for the entire garage. I can use 120v L1 EVSE, but to install a 40A L2 EVSE, I would have to replace the wire and upgrade it to place a subpanel in the garage. The problem is, in order to run the new wire to the garage, I would have to dig a trance across the asphalt driveway. The cost is not small. One estimate I got was more than $10K.

    But, I do agree with others that the use of an extension cord should be avoided. You should talk to the electrician to see how much more it would cost to extend the circuit to the garage. It may be expensive, but your garage will be far more usable. For example, you can have a power garage door opener and lightings in the garage. You can think of it as an improvement project.
     
    #9 Salamander_King, Nov 6, 2021
    Last edited: Nov 7, 2021
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  10. Ingapone

    Ingapone New Member

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    Why can’t the electrician just install a 240v outlet in your garage? What am I missing?
    Not sure why you have to have extensions and run 50 ft of wire if you could just put the outlet in the garage.
     
  11. Ingapone

    Ingapone New Member

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    And it’s awesome that you’re running almost entirely on EV mode!
     
  12. jerrymildred

    jerrymildred Senior Member

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    You are missing that there is no electricity in the garage. Gotta get power to the garage and then put in an outlet.
     
  13. Ingapone

    Ingapone New Member

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    Thanks, Jerry.
     
  14. Old Bear

    Old Bear Senior Member

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    I don't know the specifics of your neighborhood and site, but keep in mind that it is possible to install an overhead line to an "out building" like a garage. This might be more appropriate in a rural setting than in a subdivision where all utilities are underground. (It's fairly common to see this type of service used between farm buildings.)

    Depending upon your site, this could be unobtrusive and not something that is aesthetically objectionable -- or it could look really cheap and tacky.

    Overhead-Electric.jpg

    You should plan for a small sub-panel in the garage to split out 120v circuits for lighting, outlets and door openers and a 240v circuit for your EVSE. You will also need to tie the sub-panel to a local grounding rod driven into the earth.

    Obviously, you should check your local code and zoning requirements but it's a possibility worth considering. And, while you probably won't have the height and clearance requirements of a utility line crossing a public road, if you span a driveway, you do need to the height of likely vehicles like fuel delivery trucks, etc.
     
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  15. Salamander_King

    Salamander_King Senior Member

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    Thanks. I have not given much more thought to how to approach this project. The initial estimate was done by a contractor who would do the excavation but the estimated cost also includes redoing the blacktop which actually needs major repair. The actual electrical part of the installation of the subpanel and new 240v circuit and yes a separate 120v circuit in the garage was something like $2-3K. Still, that was a substantial investment that I could not justify spending at that time.
     
    #15 Salamander_King, Nov 9, 2021
    Last edited: Nov 9, 2021
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  16. jerrymildred

    jerrymildred Senior Member

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    Goor point, @Old Bear.

    And, if you must go underground, if the pavement isn't too wide or the ground too rocky, I've used a pipe on the end of a hose to water blast a hole under sidewalks before.