# Should charger have a GFCI?



## Trailhead (Mar 2, 2013)

My client bought a Tesla. I noticed his garage charger outlet(240v) doesn't have a GFCI breaker in the panel. I'm concerned, because I found the charger laying in a puddle of melted snow on the garage floor. 

Is there any reason why a 240v charger shouldn't have GFCI?

Thanks much,
TC


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## McRat (Jul 10, 2012)

Not a big fan of GFI's. Lots of people are having issues with OEM chargers.

A 240v circuit doesn't have a path to ground/neutral directly, so it doesn't do much good anyhow.


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## tomofreno (Mar 3, 2009)

Trailhead said:


> My client bought a Tesla. I noticed his garage charger outlet(240v) doesn't have a GFCI breaker in the panel. I'm concerned, because I found the charger laying in a puddle of melted snow on the garage floor.
> 
> Is there any reason why a 240v charger shouldn't have GFCI?
> 
> ...


Yes it should. I have a 50A GFCI breaker supplying a 50A connector to my charger. Has worked fine with both Manzanita Micro and EMW chargers. I've tripped the GFCI a couple times over the last 4 years...learned to not work on the car while it is charging.


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## twright (Aug 20, 2013)

I am confused as to why you can trip the GFCI by working on the car when it is charging. Can you explain that phenomena?


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## McRat (Jul 10, 2012)

For high power applications, I've never seen a GFI that didn't cause more harm than good.

For low power? Uh... Well a brand new GFI receptable that had never been used caught fire in my new garage. But that is not common. What IS common is for people to replace faulty GFI's. Measure the risk of replacing the broken hardware (they all break, just a matter of time) verses the risk of getting a shock from a non-GFI outlet.

Normal, 120vac won't kill you. That's not true for 240. You make a dumb mistake in your panel, you are touching a 100-200 amp 240vac circuit.

Don't run 240vac circuits on GFI. It's one more risk, and an unnecessary one.

But do what you like. Note that industrial buildings seldom if ever have GFI's on any circuit over 120vac.


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## sunworksco (Sep 8, 2008)

I have installed many 240volt GFCIs and haven't seen many failures.
120volt will hold you with muscle spasms but 240volt will knock you loose with a jolt. I have installed electrical systems most of my life and have been shocked every way.


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## EVfun (Mar 14, 2010)

Trailhead said:


> My client bought a Tesla. I noticed his garage charger outlet(240v) doesn't have a GFCI breaker in the panel. I'm concerned, because I found the charger laying in a puddle of melted snow on the garage floor.
> 
> Is there any reason why a 240v charger shouldn't have GFCI?
> 
> ...


For a Tesla charger you should consult the manufacture specs for what kind of power should be supplied. It may say GFCI, or it may be built into the charger. I would follow their advice on the matter as they have spent a lot of money and time designing the complete package. 

For home brew EVs I would suggest that you use 2 layers of safety. There are 3 to choose from, isolation, grounding, and ground fault circuit interruption. Don't trust that an isolation transformer will remain internally isolated, have a backup. Don't count on the conductive grounding path will remain intact, have a backup. Don't put your full confidence in a GFCI protector as they can fail, have a backup.


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## McRat (Jul 10, 2012)

sunworksco said:


> I have installed many 240volt GFCIs and haven't seen many failures.
> 120volt will hold you with muscle spasms but 240volt will knock you loose with a jolt. I have installed electrical systems most of my life and have been shocked every way.


Do what you like. 208vac at big amps will torch you like flamethrower. It smelled like burning hair and a BBQ. It happened instantly. BANG!!! I spent 2 weeks and $175k in the UCI Burn Center. 

No GFI will stop 2 hots, like 208/240/460.


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## dougingraham (Jul 26, 2011)

twright said:


> I am confused as to why you can trip the GFCI by working on the car when it is charging. Can you explain that phenomena?


You are supposed to tie the ground lead in the J1772 to your car frame and then any current flow in the ground wire trips the GFCI breaker. If you are charging and touch one hand to the car and the other hand to a battery terminal it should trip out if your charger is not isolated.


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## tomofreno (Mar 3, 2009)

twright said:


> I am confused as to why you can trip the GFCI by working on the car when it is charging. Can you explain that phenomena?


 I use unisolated chargers.


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