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Discussion Starter · #1 ·
I bought a 2017 Volt Premier two weeks ago and am having some problems with my EVSE. We own two homes and have had the EVSE refuse to charge at both locations due to open ground. We solved the issue at our main home by replacing the outlet.

At our second home, we have a detached garage that is two years old. The EVSE shows open ground in any outlet we try to use in there. A plug-in tester indicates the outlets are grounded properly. We replaced an outlet in the new garage, since that helped at the other house, but it still does not work. I can run a heavy extension cord to the main house and the EVSE works fine.

Thoughts? Is it possible my EVSE is too sensitive?
 

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The Volt EVSE does seem to be especially sensitive to the ground conditions, but that is for a very good reason.

If it were me, I'd try the EVSE in a few other outlets at other locations and see how it behaves. If it gives you trouble in all the other places then it might be an issue with the EVSE. If it works right in those other places then I'd have an electrician check out the garage because the Volt can draw a continuous 1400 watt and that is a lot of juice to pull through a bad connection which could result in fire and related bad things.
 

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The EVSE can be sensitive to noise on the ground wire of the circuit but in this case you should check all of the outlets, junction boxes and fixtures in the detached garage:

"In many cases the open ground on one outlet is the result of a disconnected wire at another outlet. A wire disconnected from one outlet will disconnect the ground service from all the outlets down line."

I get a Power Fault indication light on my Level II EVSE whenever I use my plug-in leaf blower. The blower motor adds sufficient noise on the ground line that the EVSE picks this up as a ground fault. It does not matter what outlet or circuit I use with the blower, always get a fault on the EVSE. The fault clears automatically in about 20 minutes after I finish using the leaf blower. I doubt your problem is noise on the ground line but you might leave the EVSE plugged in, not connected to the vehicle and see if the Power Fault lights clears after a while.

Always turn off the power when testing continuity of the wiring and the outlet. It could also be a neutral wire crossed with a hot wire or even a hot ground (very dangerous.) I would get an electrician to find and fix the problem.
 

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Have an electrician come and check to ensure you have a proper ground connection between the house and garage.
Does the garage have a sub panel, or is it just 1 wire for lights and outlets? If it's just 1 circuit, I would be a bit hesitant to charge on anything other than 8 amps.
 

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Discussion Starter · #5 ·
Thanks all, for the advice and the ideas on how to proceed - very helpful! To answer a question, the garage is on its own sub panel.
 

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Have the electrician check the neutral line, too. There should be NO voltage in the ground line or neutral if both are well attached at the panel. But if the neutral is weak at the outlet or in the circuit, or the neutral isn't correctly grounded at the main panel, there can be an induced voltage as the circuit is used, causing the artificial defect to happen.
 

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Sub-panels can also be tricky if they're not properly setup with neutrals & grounds separated. The panels usually come with a screw in place that bonds the neutrals & grounds. That bonding should only occur in the main panel (technically inside the main disconnect, but that's usually the main panel). So, in a sub-panel the screw needs to be removed and separate bus-bars must be used for neutrals & grounds.


If your garage sub-panel has neutrals & grounds mixed together on the same bus-bars, you could wind up with stray current on the ground that the EVSE doesn't like.


Electrician should be able to straighten it out for you.
 

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Sub-panels can also be tricky if they're not properly setup with neutrals & grounds separated. The panels usually come with a screw in place that bonds the neutrals & grounds. That bonding should only occur in the main panel (technically inside the main disconnect, but that's usually the main panel). So, in a sub-panel the screw needs to be removed and separate bus-bars must be used for neutrals & grounds.


If your garage sub-panel has neutrals & grounds mixed together on the same bus-bars, you could wind up with stray current on the ground that the EVSE doesn't like.
Actually, incorrect bonding between the neutral and ground in a sub-panel could make the Volt's EVSE less likely to fault. (though I wouldn't suggest that as a fix)

The EVSE checks for proper grounding by measuring between neutral and ground. Ideally there will be a circuit reading close to zero ohms. Problems can arise with long wire runs: a load on the hot and neutral will cause voltage drop, but the ground wire has no load and thus no drop.

Assume 100 feet of 12ga wire. If it's fed with 120.0V and loaded to 15 amps the voltage at the far end of the wire would be 115.2V between hot and neutral, 117.6V between hot and ground, and 2.4V between neutral and ground.

This isn't usually an issue for the EVSE because it's typically the only load on the circuit, but with a subpanel all of the connected loads affect the voltage drop on the cable feeding the subpanel.
 

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Discussion Starter · #9 ·
I appreciate all these responses! Much of it is over my head, but I will print this out for when I have the electrician out.

I had unplugged everything in the garage (except the garage door openers) to try to eliminate any noise, so I don't think it's a load problem.

At work we just replaced two of our fleet vehicles with EV's and our electrician is preparing to get level 2 chargers installed for these and for employee vehicles. EV charging is new to him, and he is wanting to learn everything he can. He's very interested in my problem and has offered to come out and take a look. I think I will first see if I can borrow one of the EVSEs from the fleet vehicles and see how that behaves in my garage to rule out the EVSE. If that shows a fault as well, I'll have the electrician come out and hopefully be able to fix things without too much trouble.
 

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Discussion Starter · #10 ·
UPDATE: I was able to borrow an EVSE from a Ford Fusion Energi and it works just fine in my garage, where I have been having trouble with my Volt's EVSE. Do I have a case at the dealer to get a replacement EVSE?
 

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UPDATE: I was able to borrow an EVSE from a Ford Fusion Energi and it works just fine in my garage, where I have been having trouble with my Volt's EVSE. Do I have a case at the dealer to get a replacement EVSE?
You'd have a better case if an identical Volt EVSE worked. It's possible the Ford unit is less sensitive. Problem is, if they plugin your unit at the shop, and it works, they may blame your home wiring.

But, it can't hurt to try!
 

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UPDATE: I was able to borrow an EVSE from a Ford Fusion Energi and it works just fine in my garage, where I have been having trouble with my Volt's EVSE. Do I have a case at the dealer to get a replacement EVSE?
The Volt's EVSE is covered under the Voltec warranty. If the dealership won't help, you could try contacting Chevy directly.
 
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