In OpenEVSE hardware, the ground fault CT only detects fault at EV, but what if the ground fault occurs at OpenEVSE itself, how to protect against this which is also hazardous?
You are correct, the ground fault coil detects from the coil out to the handle and vehicle. This is where a ground fault it is most likely to occur from handling and contact exposure to water in the EV a socket, handle or a damaged cord, etc.
There is no ground fault protection inside the enclosure or on the input cord. This is why UL requires short input cords. If the input cord is short and not long enough to ground, it is not likely to get damaged. By requiring a very short cord you end up with one foot of unprotected length and 25 feet of protected.
Is it hazardous? It could be, you should always use caution when plugging in any device and we would not recommend working on a device that is powered. However if the station is left plugged in and the enclosure is sealed there is very little risk.
Thank you for the reply :) It was helpful.
I have a European kit OpenEVSE purchased as kit from OpenEnergyMonitor. It worked as a charm from day 1, now a month. My EV is a Peugeot e-208.
OpenEVSE reports "No Ground" regularly. I know it is sensing the EV only from the forum and the build. The thing is: the charger delivered with the car thinks it is fine and charges at the time OpenEVSE switches off the charging a few seconds after I plug in the type 2. I have tried switching between chargers yesterday. I tried 2 times OpenEVSE and switched with the car's included charger in between. Each time the car's charger would work and OpenEVSE would report "No Ground" and switch off.
Today I opened the EVSE box for inspection but could not find anything mechanically wrong with it. I put it back together and plugged it in the car, it works again and I did nothing to it other than opening the box, checking the ground connections (they were OK) and closing it again.
I was thinking: should I tie-wrap the EV charge wires together where they go through the ground fault CT so to make sure there is as little difference in induction as possible? Or maybe low voltage wires are too close to power cables?
It sounds like you just need to increase the relay power a little. Here is the knowledge base article.