Symptom:
The ZEFNET L2 chargers occasionally report a ground fault through the ZEFNET platform. This is demonstrated in the message below:
Diagnosis:
This does NOT indicate a faulty unit, this indicates that there are issues with the grounding circuit, or noisy appliances upstream of the EVSE.
The charger monitors the relationship to ground in the building the charger is connected into and not just the circuit that the charging station is on. This goes on 24/7 even when the car is not connected to the station.
The L2 unit will automatically try to clear the Power Fault on its own 22 seconds after it was first activated. For instance, if it comes on while the car is charging, 22 seconds the L2 unit will check the ground status and if the circuit has returned to normal, the Power Fault will clear on its own and your charging session will commence. There is no Power Transfer (consumption) when the fault is active.
Power Faults point to a Ground issue. It can be caused by one of three things.
Cures:
1) An actual open to Ground.
You would see that the Power Fault light is on 24/7 and never goes off. Something has been or become disconnected in the grounding circuitry. If you can reset the circuit breaker and the Power Fault goes away, this is not the cause. The neutral terminal and the ground terminal bars in your main service panel should be connected. If there is neutral but no ground run to the plug outlet that too can cause a Power Fault.
2) A poorly made or loose connection to ground.
If the ground connection is not made tight in your junction box (where the wires meet between the L2 unit and the breaker panel) or coming off the breaker panel, you may see this. You may be able to induce by rapping on the side of your junction box with the back end of a screw driver.
3) Electric Noise from Coffeemaker and Blenders
If the Power Fault disappears for a period of time when the circuit is reset or the plug is removed and plugged back in, this scenario is the most likely. Some common household appliances generate electronic noise spikes that the L2 unit can detect and interpret as a higher impedance to ground. This scenario is intermittent by nature. The two most common culprits are Keurig Coffeemakers and Vita Mix blenders. If you have recently purchased or relocated one of those devices, I would start there. You can induce the power fault at any time, whether your car is connected to the charging station or not.
a. If you have a Keurig, press the Brew button and about 30 seconds later check on the L2 unit and see if the Power Fault light has been activated. Do the same with the Vita Mix (although you may want vary the speed a couple of times).
b. If you have neither of those devices, please observe when the Power Fault gets activated and then think about what you may have activated in your building in the last 5 minutes from when the Power Fault came on. We are looking for a source and that may be low tech, but an effective way to find it.
Summary:
Providing a new charger is highly unlikely to fix the underlying issue - the wiring issues or appliances in your building creating noise will need to be cured before determining the charger is the underlying issue.