My point about the J1772 connector was completely misunderstood. What I tried
to say is that the same type of pin in the J1772 was used for power and earth,
unlike what is normal in NEMA 4 pin connectors where the earth pin is very
different. This is to support that it should be fine to use the center pin of
a 3 pin NEMA 10-50 for earth when it is not needed for neutral which is true
for most 240V loads like charging an EV or running a welder. The US J1772 does
not have a neutral because it is not needed. Always using a 4 pin NEMA
connector for 3 wires helps to "idiot proof" the connections but costs more and
is less durable.
Everyone should remember that your house with its 120/240V loads is connected
to the grid by 3 wires to save money and improve lightning protection.
Phone/data lines and cable TV have to put up with significant common mode
voltages as a result. In remote farms this voltage can kill the animals. Last
I looked the code still allowed a 3 wire 120/240V connection to a shed if you
put in a ground rod. This causes problems with Ethernet and cable TV putting
excess current on the shield. My ground rods measure 500 to 1000 ohms because
of ledge so I plan to always use 4 wire connections to my sheds.
Phil
On Friday, February 13, 2026 at 06:19:26 PM EST, Cor van de Water via EV
<[email protected]> wrote:
The J1772 is sometimes used by RV'ers to llug in, but requires a
transformer (can be auto-transformer, meaning only 1 winding with center
tap) to create a "Neutral" as long as it only connects to the 2 hots and
keeps the new neutral separate from the ground wire.
The proximity pin is not used in the cable in America, because the cable is
permanently attached to the EVSE.
So, in the US the only use of Proximity is to confirm secure plug in,
before the vehicle is allowed to draw charge. As soon as you push the latch
on the handle, the resistance in the handle changes and the car stops
charging.
In Europe the proximity carries a resistor in the cable you plug into the
EVSE that tells what current the cable can support and the EVSE adjusts its
advertised current via the Pilot signal to the minimum of cable and its own
limitation.
The car still reads the Proximity on the car side for the same function as
in the USA.
use of the car side Proximity signal by the EVSE is optional.
Cor.
On Fri, Feb 13, 2026, 8:32 PM (-Phil-) via EV <[email protected]> wrote:
> I'm not aware of any EV or EVSE using the J1772 type 1 ground for neutral.
> This violates the standard, and would (should) instantly trip the ground
> fault detection in the EVSE and any upstream GFCIs.
>
> On the type 1 (US) connector there are only 5 pins; one ground connected
> only to the vehicle chassis and serving as reference for the 2 small
> proximity pilot (PP) and control pilot (CP) pins, and the 2 AC current
> carrying pins. One of these will be neutral if using level 1 (120v). The
> PP tells the EV a cable is connected and also the status of the mechanical
> latch, and the CP tells the EV the supplied amperage and allows the EV to
> enable AC power.
>
> On the EU spec type 2, they add an actual neutral and 1 more AC pin to
> enable 3-phase with neutral.
>
> The combo spec adds 2 large DC only pins at the bottom for DCFC.
>
> Grounds by intended design are never supposed to carry current, they are
> only used for fault handling, and to provide a return for leakage and
> high-frequency RF.
>
> On Fri, Feb 13, 2026 at 10:23 AM EV List Lackey via EV <[email protected]>
> wrote:
>
> > On 13 Feb 2026 at 7:15, DOOLEY PHILIP G JR via EV wrote:
> >
> > > using a neutral pin for earth might be a misuse, but the J1772
> connector
> > > does this.
> >
> > My first thought reading this was a bit of ignorant skepticism - why
> would
> > J1772 need a neutral pin?
> >
> > I've never used a J1772 personally, so I looked at the description here.
> >
> > http://evdl.org/docs/j1772description.pdf
> >
> > On the first diagram on page 2, titled J1772 Interface, I noticed 2 extra
> > pins, not shown as in use in the diagram on the first page.
> >
> > Page 3 has a full pinout for the connector. It does indeed illustrate 3
> > large (presumably high current) pins. It describes them as mains, mains,
> > and ground/neutral.
> >
> > Combining ground and neutral that way is reminiscent of the bad old days
> > of
> > US 3-pin 30 amp clothes dryer and 50 amp electric range connectors. It's
> > very surprising that the J1772 designers thought that way.
> >
> > One more puzzle -
> >
> > In addition to the smaller pilot pin, there's a second smaller pin
> > described
> > as no connection.
> >
> > Now I wonder what that "no connection" pin might have been reserved for
> in
> > the original J1772 specification. Does anyone know the history?
> >
> > David Roden, EVDL moderator & general lackey
> >
> > To reach me, don't reply to this message; I won't get it. Use my
> > offlist address here : http://evdl.org/help/index.html#supt
> >
> > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
> >
> > First they came for the journalists. We don't know what
> > happened after that.
> >
> > -- Unknown
> > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
> >
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