So my portable EVSE seems to detect a ground fault when I try to charge at work. When the error condition is sensed, both lights blink red. This only happens when I try to charge, I can leave it plugged in to keep the battery warm without any issues.

The electrician at work recently used a little device to measure ground continuity etc. and everything looks fine. He also measured the voltage and it reads 119V. He said the contractor most certainly used a minimum of 12 gauge wiring, so it seems like a voltage drop issue shouldn't be a problem.

Does anyone know what else might cause an issue here, or how I would help my place of work to identify it?

I should also note that this same portable EVSE charges my car at my own home every night without any problems.

Have you tried setting the EVSE to 8 amp mode? I had a similar issue once at a hotel. While 8 amp mode worked fine, 12 amp caused a fault condition.

I thought I read some where this could happen if the neutral and hot was reversed.

Have you tried setting the EVSE to 8 amp mode? I had a similar issue once at a hotel. While 8 amp mode worked fine, 12 amp caused a fault condition.

Yes, I had the same issue with 8 amp mode.


I thought I read some where this could happen if the neutral and hot was reversed.

Perhaps, but I would've thought that the little tester that was used for ground continuity etc. would flag this condition.

So, if it works while not charging, then fails when trying to charge, it must be related to the current draw. Did the eletrician read 119V with no load? Have him measure it with a decent load like a blow dryer (you know I don't use one).
Even the outlet I use in my old house (with fuses) reads over 119V while charging the Volt.

Hopefully there might be a clue given how a GFCI functions:

The hot and neutral legs go through a detector. If the current between the hot and neutral legs aren't exactly the same, it will detect an imbalance and open the circuit.

For example, if any current is being leaked through the ground leg an imbalance occurs. An extreme example would be that the car might be touching something "grounded" and current could be leaked through that.

If the detector is too sensitive, in theory even static electricity could cause it to trip...

I had a very long discussion with my Chevrolet dealer today about the 120 volt charger. There is one interesting area that GM may be trying to clear up. The owner manual says to plug into a GFCI, but the owner manual only mentions it if using an extension cord. Whatever GM says in the manual is for safety first. My dealer said that I should be using a dedicated non-GFCI 20 amp outlet in the garage. I will be requesting more information that will improve the use of the charger after the meeting that is scheduled between GM and the dealer's technical staff.

Here is an interesting find on the web that would disagree with the dealer, as garages should have GFCI outlets. Maybe that is why Leviton plans to cover their dedicated outlet with an outdoor cover installed in the garage to prevent tampering.

http://forums.mikeholt.com/showthread.php/128721-EV-chargers-with-Integral-GFCI?

Meanwhile here is a tip from dealer information: When both fault lights flash red and the dashboard light is yellow:

1. The outlet may not be dedicated.
2. The outlet may have a ground fault.

The charger is designed to reset itself and may start charging again until another ground fault is detected.

In my garage, I opened the cover plate that hides the ground rod for the circuit breaker panel. Tightening all the screws and bolts has improved my red light situation so far. No faults today with a GFCI 15 amp circuit. The dealer was not concerned that the voltage on that line dropped from 119 to 115 while the charger was on. However, they want me to use the dedicated 20 amp circuit. One more thing... according to the dealer service department, the supply plug in wire will get warmer as voltage drops. Using an outlet that is closer to the circuit breaker panel with a larger gauge wire (i.e. #12 instead of #14) should improve the voltage. My experience is that using the charger outside in a breeze also helps cool the charger supply wire and plug.

The owner manual says to plug into a GFCI, but the owner manual only mentions it if using an extension cord. Whatever GM says in the manual is for safety first. My dealer said that I should be using a dedicated non-GFCI 20 amp outlet in the garage.

So that I can use a non-GFCI outlet safely, I bought a Leviton 16593 GFCI plug (Amazon, ~$17) and replaced the plug on the extension cord with it. Works quite nicely.

So that I can use a non-GFCI outlet safely, I bought a Leviton 16593 GFCI plug (Amazon, ~$17) and replaced the plug on the extension cord with it. Works quite nicely.

The owner manual agrees with you. Quote: "The 120V AC outlet should be GFCI protected. The extension cord should be: GFCI protected. 12 or 14 gauge, 3 conductor. Rated for outdoor."

How do you protect yourself when plugging into the first outlet. Gloves?

How do you protect yourself when plugging into the first outlet. Gloves?

The several times I've taken 120V it hasn't seemed to bother me, so I don't worry about it. :cool:

Thanks all,

I found another outlet at work that does work, and I'm going to do some more testing on the other one with the electrician at some point, while my car is plugged in.

I was told that the tester he used checks for outlet polarity, loss of neutral, hot or ground, etc.

We'll see if perhaps it's a current imbalance between hot and neutral when a load is present as suggested above. I doubt it's just a voltage drop as my employer is typically very adamant about making sure we have great facilities, wiring and all, but I'll double check there too.