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J1772 Cable - Pilot Proximity wire - Really required?

I am just curious why your design even bothers with the Pilot Proximity in the controller and cable. Todays EVE cable standards call for basically 3 power + 1 control wire cable. My Hyundai charger has a EVE cable with 3 + 1. "Proximity" is basically built within the plug and is a "wake up" mechanism for the EV rather than the chargers.

I can envision the Proximity wire being used in a commercial setting where you would want to know if the EV was connected and using a parking spot and keep charging the consumer in a hope they move the car for the next party to park and charge.  But fail to see any benefit for a non-commercial setting, specially with the extra wire adding to cable cost, bulk, weight and not providing any significant ROI in return.

Is proximity just a legacy component that stayed with the design and was never reviewed? 


Al you are confusing proximity with proximity pilot (PP). 

Proximity pilot is used in the IEC standards to identify the ampacity capabilities of removable cables. For example a 32A Type 2 cable has a 220 ohm resistor between PP and Earth, the vehicle and station read this value and limit current if needed.

Proximity is the button/resistors at the end of the cable between the handle and EV, there is no use for this in the charging station.

So since OpenEVSE gear is based entirely on non-tethered (attached) cables, IEC 62196 on using the PP wire is irrelevant,  Correct?

Incorrect, OpenEVSE is not based entirely on non-tethered cables.

OpenEVSE has customers around the world, the controller is designed to universally support US and European standards, manufactures and customers. You are correct PP is irrelevant to tethered stations in the US, but for a couple cents (2 resistors, a diode)  PP allows OpenEVSE based products like this one from the UK to exist. 


Thanks for mentioning the broader scope of OpenEVSE and the understandable justification on the Proximity Pilot integration. 

Just to resurrect this to understand why the confusion over proximity using a J1772 latching switch and proximity pilot that restricts amperage based on cable size.

both are resisters between PP & P-E.

As an extreme example if you are using a tethered J1772 12A cable to an EVSE, 

The J1772 switch would latch between 150 ohm and 480 ohm pressed to disconnect.

But you would also have a 1500 ohm to restrict to 12A.

is this not so? Which is why the EVSE has a range.

Also do older type1 chargers like the Zero charge tank not need the signal to turn off the charger , rather than vehicles with type2 just using it as a proximity signal.

Cit wiki.

Current capability of the cable assemblyRc (±3%)Recommended interpretation range by the EVSE
13 A1.5 kΩ / 0.5 W1–2.7 
20 A680 Ω / 0.5 W330 Ω – 1 kΩ
32 A220 Ω / 1 W150–330 Ω
70 A single phase / 63 A three phase100 Ω / 1 W50–150 Ω

@ Richard

PP is for Europe IEC only with socketed stations (user brings their own cable) the American SAE J1772 does allow for socketed cables and does not have a need for PP.

Both are NOT between PP and PE.

-Proximity is between the (J1772 defined) Proximity Pin/switch/resistor in the handle and PE

-PP is from the (IEC defined) PP wire to PE

A tethered 12A station would have the pilot set to 12A, the station is tethered so users do not bring their own cables with differing capability.

I have a charging cable that came from a Siemens Versicharge EV Charger.  There are only 4 wires, the three thicker wires for power and then a blue thin wire.  There is no 5th wire.  Is one of the pilot wires unnecessary?  When trying to check which pin the wire went to there was no continuity to any of the pins.  Which pin should it connect to?  Thanks for any information.


Proximity pilot (PP) is Europe only. It is used on stations with removable cables. The EV owner brings their own cable. 

It is used, so the station knows the capability of the user supplied cable.

For stations with an attached cable this feature is not needed.

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