Agree but not sure if it's safer but don't some people use a plug with a resistor(not sure of value but for sure in K-ohms) to bond the neutral to ground? I believe this fools the check but still has some degree of isolation between ground and neutral.....
Thanks, it makes sense explained that way- Duosida must not have the ground check circuit.....nlspace wrote: ↑Wed Oct 21, 2020 5:25 amThe OEM EVVSE has an internal circuit which does a ground check before it will turn ON. It intentionally shorts out the input leads to ground to measure a current and verify that a path to safety ground exists.
Ground in your Mains panel is the mid-point of the transformer secondary on the pole at the street and the metal rod driven into the earth, which is also connected to the Neutral of the Line-Neutral pair of wires that provides 120vac. So both the 120 Line-Neutral and the 240 Line-Line have a path back to the earth thru the green ground wire in the connector plug.
But your step-down transformer is an isolation transformer--the secondary is totally isolated from the primary. So neither leg of your secondary has any connection path to ground or protective earth even if you run a wire from the panel or right at the transformer. So the ground test fails in the EVVSE and it won't turn ON.
You would need to connect the "Neutral" (wide blade of the 120vac plug, white wire) side of your isolated secondary to the green ground wire in order to pass the check.
This same issue can occur when trying to use a portable generator to supply AC for the EVVSE--unless the Neutral is tied to Ground it will fail the internal check.