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Upgrading from NEMA 14-50 50amps to HPWC 60amps

Discussion in 'Model 3: Battery & Charging' started by jgd108, Aug 22, 2018.

  1. jgd108

    jgd108 Member

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    Quick question.. I searched all the Tesla forums and just wanted to confirm a few things..

    Will be getting a HPWC and I currently have a NEMA 14-50 with a 50amps breaker.
    I would like to replace the outlet with the HPWC, hardwired if possible since I want the 60amp breaker and 48amp max charge.. if I pigtail into the outlet it won't go above 40amps charging.

    What do I need to check cabling wise with the electrician who did the outlet so I know if the cabling needs to be "ugpraded" or if I can simply cap off the white cable and get the HPWC hard wired?

    Also for the breaker is it possible to swap it to a 60amps ? Or I'm missing something here.

    FYI I'm getting solar and getting a 225A panel so I will have plenty of space in my new panel (coming from 125A).

    Thanks!

    (oh and please no philosophical discussions about NEMA 14-50 being enough etc., I'm getting a free HPWC !)
     
  2. Big Dog

    Big Dog Member

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    likely need a higher gauge wire (4?) to support the 60 amp circuit and a new 60 amp breaker in the panel. (The latter is cheap.)
     
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  3. SSedan

    SSedan Member

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    FWIW 3 gauge copper for a 90/100 amp circuit is $1.02 per foot from Home Depot, 2 big ones needed and can probably use one of the existing wires if THHN as the ground.
    Breaker will be $20-30 more than a 60amp.
    You are already spending money to upgrade might as well future proof I think you will find the cost difference minor.
     
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  4. brkaus

    brkaus Active Member

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    #4 brkaus, Aug 22, 2018
    Last edited: Aug 22, 2018
    You need to know the gauge of the wire & type (romex or THNN in conduit), Distance would also be interesting if it is a long distance.

    You could probably just ask the electrician that wired the 14-50 if it is capable of handling 60A w/o replacing the wiring?

    You would likely want 4ga wiring for a 60a Circuit.
     
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  5. Terthen

    Terthen Member

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    You could also consider asking your solar installer. We had ours include installation of a 14-50 outlet, I bet it’s something they could handle for a reasonable cost.
     
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  6. jgd108

    jgd108 Member

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    You guys are awesome

    I came back tonight and looked at my panel, and this is what is written to the best I could tell in the dark, it seems like it is saying Southwire 3 AWG THHN - this is the red wire, there was a white and black as well all same size.

    That's not big enough for 60amps right?

    Also the run from panel to other side of 2 car garage is roughly 40 feet long, with a few "shoulders" so not sure if that's an important factor for going to bigger size wire (I remember the electrician saying they can't bend much more the wire).

    The problem with using the solar electrician is I will be getting the HPWC after they do the panel upgrade..
     

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  7. NickFie

    NickFie Member

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  8. jimmyz80

    jimmyz80 Member

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    I'm pretty sure that's 8 AWG, not 3 AWG. So it would be good for 55A max, or 44A delivered to the car. You'd need 6 AWG THHN in order to support a 60A circuit with 48A delivered to the car.
     
  9. Big Dog

    Big Dog Member

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    They could still upgrade the wire to the 14-50. Then, when you are ready for the WC, you are just need to pop in a new breaker.
     
  10. jgd108

    jgd108 Member

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    Cool, a wire like this one?
    Southwire (By-the-Foot) 6 Black Stranded CU SIMpull THHN Wire-20493399 - The Home Depot

    So roughly 40 feet of wiring, 2 wire (black and red, no need for white right)? And a ground wire or not needed?

    At 84cents/foot, 2 wires X 40 feet that's $67 of cables, and a 60 amps breaker seems to be about $10.


    Great idea! And could they install the 60 amps breaker too in the panel, or should I leave the 50amps? I.E. would NEMA 14-50 work with 60amps over 6 AWG THHN wire?
     
  11. eprosenx

    eprosenx Active Member

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    So what matters is the ampacity of the wire and what type of wire it is (and what if any conduit it is in).

    No, this depends on what kind of wire and if it is in conduit. I have #6awg in conduit which is good to 65 amps. I have it on a 60a breaker.

    3 AWG copper in conduit is good to 100 amps. If your conduit is large enough and your new service has enough capacity then this would be the most optimal setup for a HPWC for whatever the future may hold (a M3 can only take up to 48a which needs a 60a breaker). It would support up to 80a continuous.

    6 gauge in conduit is fine for a 60a circuit.

    As others have noted, that really does not look like 3 AWG. 8 AWG is more likely. 8 AWG in conduit is good to exactly 50 amps (40a continuous) so that makes sense.

    The important thing we need to know is how large the conduit is from the breaker panel to the receptacle? Is it EMT style conduit? Can you post a picture? This will dictate the largest wire you can run in that conduit.

    100a if installed in conduit. (80a continuous)

    Ampacity Charts

    No. You can't read the 90c column. The HPWC or receptacle and breaker are nearly guaranteed to be rated to 75c, so that is the limiting factor.

    Yes, #6 awg copper THHN in conduit is fine on a 60a breaker which will give you 48a continuous for your HPWC. You might technically be allowed to use the conduit as the ground, but I would recommend running a dedicated ground. You need a 10awg for up to a 60a circuit. Up to 100a needs 8 AWG.

    You can't upgrade the breaker to 60a even if you upgrade the wire as you are not allowed to put a breaker over 50a on a 14-50 receptacle.
     
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  12. jgd108

    jgd108 Member

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    Thanks @eprosenx for the detailed reply.
    I'm checking out for the night but attached some more pictures in my garage for size of conduit.
    That was my worry of upgrading the cabling and breaker while keeping the NEMA 14-50 outlet until the HPWC arrives, that the amperage would be too high.
    Also thinking based on my current outlet and conduit how to wire the HPWC with the feed coming from above.. :) Maybe mount it on the right side of the conduit?
     

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  13. eprosenx

    eprosenx Active Member

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    That looks like 3/4in EMT conduit.

    So your cheapest option to max a M3 charging rate is a black and a red #6awg copper line plus a green #10 for ground. 60a breaker.

    Alternatively, you could do a black and a red #4awg copper line plus a #8 ground. 80a breaker. 64a max continuous charge rate setting on the HPWC. You can't fit #3 in that conduit.

    For running the conduit, you have many options. You could potentially just come direct into the top of the HPWC without any modification to the conduit, or you could modify the conduit height by shortening it and still coming into the HPWC top directly, or if you wanted it further to the right where your cord reel is currently you could use the existing electrical box as a pull box and run conduit between that and the bottom of the HPWC. The HPWC is in and of itself a cable holder, but you could I guess put the HPWC where the receptacle box is and still use the existing holder?

    Good luck! Report back when you figure out what you are going to do and post pictures when done!
     
  14. Alketi

    Alketi Member

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    You can install larger wire, but the Model 3 charge rate maxes out at 48A (60A breaker), so an 80A breaker and larger wire will gain no additional charge rate improvements.

    Home Charging Installation
     
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  15. brkaus

    brkaus Active Member

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    I’d go for what fits in the current conduit. Charging to WC does allow you to drop the neutral, so you gain space over the current wiring.

    If you add another car later, pick the wire/conduit that best matches that car.
     
  16. SSedan

    SSedan Member

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    I would ask for quotes for the largest wire that will fit in the existing conduit and a quote for a 90-100amp circuit run even if it means replacing that conduit. I know this car can't make use of but maybe a future car or second car with load sharing could later. With the panel upgrade you should have capacity.

    The reason I suggested considering the 100amp install is the additional cost of wire that everyone stresses over is minor. He is looking at a 40ft. run and $.86 a foot wire, I am suggesting $1.02 a foot wire. Just spitballing here but that is what $15 difference on the conductors A 100amp breaker is $50ish where smaller ones are $10-20 so the $30 difference? When paying someone $100 an hour or whatever labor is why wouldn't you future proof. The snag here is the conduit, personally if they told me $200 to upgrade the size of that I would jump on it, if they said that adds $800 I would likely pass

    Learn from the mistake of having already been done "barely good enough" once and now are paying to upgrade, you want to do this all over again in a couple years when you somehow outgrow this?

    I say this having make the "just good enough" mistake too many times wasted a lot of money redoing things, long term a bit of overkill is almost always cheaper.

    1 1/4" plastic conduit is $5.40 a 10foot stick plus fittings, the 3/4" metallic you have is $6.20 a 10foot stick but requires fewer fittings due to being bendable. So the cost difference up front on conduit materials would have been negligible and the initial wire cost for 40ft. at $.56 a foot for 3 pieces of 8gauge(ignoring smaller ground for simplicity) was $67 where the 2 pieces of 3 gauge for a 100amp HPWC install would have been $82 and the breaker would have cost $30 more That is a whopping $45 difference in wire and breaker cost to go all out instead of bare minimum.
    Now granted project cost will be more due to larger wire being harder to handle, maybe the 1 1/4" plastic conduit takes longer to assemble than 3/4" metallic, but the cost to put big wire in then even if using a 14-50 for a year or two would have been a lot less than you are spending today. Learn from the mistake.
     
  17. gavine

    gavine Petrol Head turned EV Enthusiast

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    Looking at the wire picture, that is definitely an "8". There's a "3" near it and you can clearly see the difference. I agree that the 8 looks like a 3 at a glance, but once you see that other 3, it's obvious.
     
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  18. jgd108

    jgd108 Member

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    You guys are awesome! Thanks a bunch.

    I'm attaching some pics of the panel before and after the quad breaker was added to fit in the 50 amps.

    So to recap, I just need a 60 amps breaker, maybe a 20 amps breaker for the previous circuits attached to the 50 amps, and 50 feet (to be safe and cheaper for that increment) of black, red and green #6 awg copper THHN.

    And cut off some of the conduit to plug directly from above into the HPWC.

    One more thing I realized.. if there's enough space on the left since the cabling will be taking space and it has to be on a stud.

    I measured 11 inches from the center of the conduit to the wall on the left, and the nearest stud is on the right about 7 inches (16in studs).. so I might have to put it on the next stud which is where I put the cable holder with some more tubing..

    Back up plan: pigtail from the outlet to the HPWC but only 40amps charging.
     

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  19. EVDRVN

    EVDRVN Member

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    Lot's of work and cost for 8 more amps of home charging, are you an Uber or Lyft driver? Whey the need for that 8 amp increase? The benefit is almost moot since you already have 40A charging. A M3 pack is small in relation to a 100, how many miles do you drive a day?
     
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  20. SSedan

    SSedan Member

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    UMC Gen 2 is 32 amps so this is a 50% upgrade and the UMC can sit in the car as a backup.
     
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