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NEMA Questions

Discussion in 'Prime Plug-in Charging' started by Rebound, Jun 2, 2019.

  1. Rebound

    Rebound Senior Member

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    I need some help choosing the correct NEMA 240V connector. I just picked up a used GE WattStation EVSE. It can support up to 240V 30A, requiring a 40A circuit. BUT — it has a jumper inside, which lets me select whether the input circuit is 240V at 15A, 20, 30, or 40. This causes the EVSE to indicate that it can supply a maximum of 12A, 16A, 24A and 30A respectively.

    It has a 240V NEMA plug (40A, I assume). I’m going to mount it in my garage right next to my fuse box.

    I thought I’d use a 240V 20A breaker, since my Prius Plug-in can’t draw more than about 12A. (The WattStation manual says it has internal protection and so a GFCI breaker isn’t necessary; this unit is being installed inside a garage, not outdoors). I can just buy a new pigtail with a NEMA plug and attach it inside the EVSE, and then use the corresponding plug. Which NEMA connectors should I get for 240V 20A? The WattStation manual says the EVSE needs only Line 1, Line 2, and Earth ground.

    When I look at the NEMA chart, there are several possibilities, so I’m confused. Thanks in advance!
     
    #1 Rebound, Jun 2, 2019
  2. Rob43

    Rob43 Senior Member

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    What exact 240v plug is currently on the end of your used GE WattStation EVSE unit ?

    EDIT: I just looked this unit over with a web search, looks like a hard wired EVSE.


    Rob43
     
    #2 Rob43, Jun 3, 2019
    Last edited: Jun 3, 2019
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  3. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Some time in the Future, you will want all 30 Amps, so you definitely want 8 gauge wiring to the receptacle. So that in the future you do not have to rewire.. You could put a 40 Amp receptacle on that right now, except that NEMA does not define a 40, they jump from 30 to 50 Amp. So lets pretend 50.

    "The WattStation manual says the EVSE needs only Line 1, Line 2, and Earth ground." The NEMA 6 series fit this description. . (NEMA 10 and 14 is common in dryers and stoves, where you need both 240 and 120 Volts, so have more blades than we need. NEMA 1,2, 5, 7, 11, 15 and 18 are for other voltages or 3 phase equipment, we can ignore them. 1, 2, 10, and 11 do not have a Ground, avoid them)

    [​IMG]

    Now you could use a 20 Amp breaker now, that would be slightly safer until you need more Amperage, or get a 40 Amp Breaker now and just be all done with it. Both 20 Amp and 40 Amp Double Pole Breakers are common.

    6-50R part list
    www.amazon.com/EATON-1254-BOX-50-Amp-250-Volt-Receptacle/dp/B000GAX88U
    www.amazon.com/Leviton-4934-Receptacle-Wallplate-Standard/dp/B000FP8IE0
    www..amazon.com/Hubbell-Raco-683-Device-8-Inch-Knockouts/dp/B00004WZ2E
    www..amazon.com/Cerrowire-147-4002A-25-Feet-Stranded-Ground/dp/B00LU6816S

    The Breaker has to match your service, I can't guess that.

    A 6-50P plug
    www.amazon.com/EATON-S42-SP-L-Commercial-250-Volt-6-50-NEMA/dp/B000VL6X22

    But seriously, you have a hard wired EVSE, hard wire it with 8 gauge wire and save all the (more) dangerous plugs and receptacles.
     
    #3 JimboPalmer, Jun 3, 2019
    Last edited: Jun 3, 2019
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  4. Rebound

    Rebound Senior Member

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    It’s available in hard-wired and corded versions. Mine has a NEMA plug in the end of a cord, but I can easily remove that cord and replace with another. Pretty sure I can also run conduit directly into it and bypass the NEMA receptacle need, which I might do.
     
    #4 Rebound, Jun 3, 2019
    Last edited: Jun 3, 2019
  5. Rob43

    Rob43 Senior Member

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    I gave this a bit of thought, if it were me I'd:

    1) Install a 14-50R receptacle in your garage because it's very standardized.

    2) Wire your used GE WattStation EVSE with either a 14-50P or 6-50P plug. If you use a 14-50P, wire it as a Hot-Hot-Ground, thus the neutral terminal is not touched. The reason you can also use a 3 prong 6-50P plug is because they perfectly fit into a 14-50R receptacle.

    Good luck with your decision.

    Rob43
     
    #5 Rob43, Jun 3, 2019
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  6. Tha_Ape

    Tha_Ape Active Member

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    The Prime can draw 16A.

    From reading here, that reduces the 240V charge time by about 20% over the 12A 240V charge time. (~30min). That may not be enough for you to care about, just giving some info.
     
    #6 Tha_Ape, Jun 3, 2019
  7. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    There is no trouble drawing a sustained 16 Amp through a 20 Amp breaker.
     
    #7 JimboPalmer, Jun 3, 2019
  8. Rebound

    Rebound Senior Member

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    That’s correct. If I put the EVSE on a 20A breaker, it will tell the car that it can draw up to 16A.
     
    #8 Rebound, Jun 3, 2019
  9. Tha_Ape

    Tha_Ape Active Member

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    That's exactly what I'm using, too. A NEMA 6-20 outlet.
     
    #9 Tha_Ape, Jun 3, 2019
  10. Rob43

    Rob43 Senior Member

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    Something has been irritating me all day, I realized my highlighted sentence is a straight up mistake; a 6-50P plug does NOT fit into a 14-50R receptacle. I confused all of this with the common 14-30P plug, a 14-30P plug perfectly fits into a 14-50R receptacle (and vise versa) once the neutral leg is removed. So both the 14-50P plug and the 14-30P plug will work great for application because you're only using a max of 16 amps, if you go this way wire them as: Hot-Hot-Ground.


    Rob43
     
    #10 Rob43, Jun 4, 2019
    Last edited: Jun 4, 2019
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