Stray AC voltage while charging?

[WetOne]

It was a long drive home the day we got our Spark EV, requiring a four hour charge at the Aerovironment Kiosk. At one point during the wait, I wanted to peek at the motor compartment, so I popped the hood release, then walked to the front of the car. As I reached under the partially released hood to find the safety catch, my finger touched something, and I felt the unmistakable sensation of a 60 hertz AC voltage shock. It was strong enough for me to quickly retrieve my hand from under the hood, but not enough to cause any damage or lasting pain.
Has anyone picked up stray AC voltage under the hood or any other place on the car, while charging? I assume there is no AC current present on the car when it is not plugged in.
Is it advised to leave the motor compartment closed while charging?

 

[jayfay]

Yuck, thats not good to hear. There should be no reason you cannot open the hood during charging and if there was there should be a latching mechanism to prevent opening during charging. I know at least one PHEV had a case where under-hood fans would run during charge cycles that were unsafe to work around while running. The vehicle would stop the charge cycle if the hood was opened. Technicians would have to put the vehicle in a certain mode to maintain charging with the hood open. It would surprise me though if you cannot open the Spark EV during charging. And like I said, if there was a danger the vehicle should go into a safe state upon opening. I even think there is a specific FMVSS requirement that calls for this and I am doubtful that GM would miss it.

Regarding what you felt I would put my money on improper installation of the charge station, like improper bonding and grounding. Normally I would suspect static discharge but it sounds like you know too well what 60Hz feels like

 

[WetOne]

Thanks for the input. I checked under the hood today and the only metal item in that area is the bolt head that holds the safety latch. It had no voltage on it today, either standing idle or while on a ( different) charger. I believe this supports the theory of a poorly grounded/bonded charger.
Had a great drive today. 150 miles with one long stop for a charge. 5.1 miles/Kw with some major hills, highway speeds.

 

[lalacurf121]

Normally I would suspect static discharge but it sounds like you know too well what 60Hz feels like
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[NORTON]

Sounds like improper grounding of the charge station.
You should report it to anyone one that will listen. The business hosting the site, the EVSE maker, the network (if there is one), Chargepoint (maybe even if they are not the network, they may tell you about another reporting method.

This is UNSAFE . Please, for the safety of others report the hell out of this before someone gets hurt. Tell the business site to open the breaker until this gets resolved.

And this situation could be measured with a simple multimeter if you had enough test lead wire to reach a known good ground. Do not use any metal post or anything related to the EVSE.
Perhaps a water faucet nearby? Ground to bare metal on the car frame, like the door latch. Be careful, or skip it if you don't feel comfortable doing this.

 

[nikwax]

It could be a ground fault. Which could be fatal.

 

[ImTedBell]

I thought the EVSE had a GFCI in it that would cut power if ground fault occurred?

 

[nikwax]

right you are:

http://tec.ieee.org/2013/09/29/safety-electric-vehicle-supply-equipment/

 

[kevin]

I thought the EVSE had a GFCI in it that would cut power if ground fault occurred?

A GFCI only trips when there is unbalanced current to ground - a missing ground connection resulting in the car having a voltage on its chassis would not necessarily cause any fault indication until there is enough current flowing to trip it (5ma).

You can feel a current as tingling with far less current flowing - probably a few tens of uA, way below the trip current.

A bad connection to ground could cause that effect - the capacitance from the AC to the car chassis (e.g. in the EMI filter) could result in a voltage on the car.

I have had that with scopes when I intentionally float the ground to measure a low level signal and wanted to avoid interference from noise on the AC ground.

kevin