I recently moved to California, leaving my previous OpenEVSE in Canada with my parents who now also have a Volt. I built that one with a NEMA 14-50 connector, and they installed a supporting circuit in the garage. I now plan to build a new one for myself. I would again like to use the NEMA 14-50 connector as the main AC connector.
In the garage of the house I am renting, there is a NEMA 10-30 socket for an electric dryer. If I make a NEMA 14-50 to NEMA 10-30 adapter cable, where ground on the 14-50 is tied to neutral on the 10-30, will this work with the OpenEVSE? Current ratings are not an issue because a) I will set the unit's max current appropriately, and b) the Volt does not draw that much current. It's really just the lack of an actual ground connection that I am wondering about.
Will it work...most likely BUT... It is a violation of the NEC to use Neutral as a Ground and could potentially be unsafe.
For clarity, is this because NEC explicitly requires 4-wire grounded circuits for EVSEs, despite allowing 3-wire ungrounded circuits in existing installations for things like ranges, dryers, cooktops, etc.?
I'll know more once I move in in a couple weeks, but my ideal solution is to have the receptacle replaced with a 14-30, if there is a ground present in the wire run. Then I can do 14-50 to 14-30, with appropriate current limit on the OEVSE. (Actual, my ideal solution is to have a new 50A circuit run to a dedicated outlet, but that's more $$$ for the landlord).
3 wire with 2 Hots and Dedicated Ground (not neutral is required) is okay. The Neutral could be shared and may to carry current, so it is not a good idea to tie safety/equipment grounds to a Neutral.
I was planning on building mine (the 50A 240V version) with a 14-50 plug but without the neutral pin so it can also plug into a 14-30 dryer plug (since the neutral is the keyed pin). There is no neutral wire going into the 240V 50A OpenEVSE.
This had been recommended on other forums. Is this not a solution for Scott?
I should have added to my other comment that I realize there is a safety issue if you plug the OpenEVSE 14-50 plug (without neutral pin) into a dryer outlet if you have not programmed the OpenEVSE down in current to limit the maximum draw. Well at least I presume it would just trip the breaker on the dryer circuit.
ok weird I don't see my first comment. Maybe now we will get a duplicate post.
I had said that I was planning on building my 50A 240V OpenEVSE with a 14-50 plug with the neutral pin missing so that it could plug into a 14-30 dryer outlet too as I had seen this recommended on other forums.
Is this not a solution for Scott?
There is no neutral wire going into the 240V only kits so no need for the pin on the 14-50 plug. The neutral pin is the one that is keyed and removing it allows the plug to fit into a 14-30 receptacle.
OpenEVSE does not require a Neutral but it does require a Ground.
Scott is using a NEMA10 - 30 which is missing the Ground.
Oh sorry was confused. I was talking about a NEMA 14-30 which is the typical plug for a dryer. He mentioned a dryer so I assumed 14-30 but now I see his post says 10-30 which is typically for welders or something. https://en.wikipedia.org/wiki/NEMA_connector
NEMA 10-30 is typical of dryers in older American installations, likewise NEMA 10-50 for older electric range installations. Existing installations are grandfathered, but (if I understand correctly) new installations must be NEMA 14-x variants.