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NEMA 14-50 AMP?

Discussion in 'Model S: Battery & Charging' started by Jason Shelton, Jun 8, 2016.

  1. Jason Shelton

    Jason Shelton Member

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    I've been researching and couldn't find any answers about my specific question. Is NEMA 14-50 limited to 40 amps? Or no? My Tesla is the updated model so I have the 48 AMP charging. Will a NEMA 14-50 be able to charge at 48 amps? Or is it limited to 40 amps? If it is limited to 40 amps will I have to purchase the HPWC to get the full 48 amps? Thanks!
     
  2. Max*

    Max* Autopilot != Autonomous

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    The NEMA 14-50 is meant to supply 50A max. But if you're using a continuous load, like an EV charging, it can only do 40A max (and the Tesla won't let you go above 40a in the car). So yes, if you want 48A, you need a HPWC with a 60A breaker.
     
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  3. rhumbliner

    rhumbliner Member

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    For continuous duty you must reduce your amperage to 80% of rated capacity which means 40 amps in this case. The Tesla supplied 14-50 adapter will do that for you. This topic is covered all over these forums. Search especially for posts by @FlasherZ and @Ingineer for more detailed info.
     
  4. MorrisonHiker

    MorrisonHiker Beta Tester

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    Yes
    No
    Yes
    Yes
     
  5. linkster

    linkster Member

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    Doubtful you'll need the extra 8 amps. Several forum members actually turn down their 14-50s so that the UMC runs cooler. Approximately 3.5 years/60,000+ miles here with 80 and 160-mile commutes deploying "only" a 14-30 (24A).

    Good-Luck!
     
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  6. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    Not only will you need an HPWC (or another EVSE rated to charge at 48A), but it will need to be on a 60A circuit, not a 50A circuit. Charging loads (see NEC art 625) are considered "continuous loads", and that means that all equipment (conductors, breakers, receptacles, boxes, etc.) need to be rated at 125% of that load.
     
  7. Jason Shelton

    Jason Shelton Member

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    Thanks everyone! I'll just stick to the NEMA 14-50. It'll serve me right. Thanks!
     
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  8. travwill

    travwill Member

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    All good advice. Just remember you really never want to exceed 80% of a rated amp breaker/wires with a continuous load - they will overheat/melt/etc in time. Simple calc.
     

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