110V charging w/ Tesla provided cable

[Solarman004]

by clicking out I mean what Solarman said. The GFI socket pops. All I have are GFI sockets in the garage. And I confirmed I have the correct wiring by buying the circuit checker.
So I am therefore not able to charge using the 110V provided cable?
My intention was not really to charge since I have a Level 2 charger in the garage. It was more to leave the car plugged in during long periods when I travel out of the country. This seems ideal to maintain a 50% charge to me.

@Enz295 , Here is another technique to try. You most likely have 15 amp circuits in the garage. Before plugging in, set the car to charge at 9 amps max. Then plug in. If your GFI doesn't trip after a few minutes, go to 10 amps. Keep doing this until you reach 12 amps, then stop. The maximum continuous current shouldn't exceed 80 percent of the breaker rating. That would be 12 amps for a 15 amp circuit.
If the GFI trips at sat 11 amps, just set your car to charge at 10 amps. This will be slow charging, and you won't be able to pre-heat, but it will work. I've had to do this when staying at an old house and using a long, undersize extension cord. I maxed out at 9 amps, but it worked.

 

[FlyF4]

If it only does the check once, can you hold the reset button down while you plug in?

Yes, but that depends on the type of GFCI (the manufacturer). Some won't allow you to do that.

 

[Rocky_H]

@Enz295 , Here is another technique to try. You most likely have 15 amp circuits in the garage. Before plugging in, set the car to charge at 9 amps max. Then plug in. If your GFI doesn't trip after a few minutes, go to 10 amps. Keep doing this until you reach 12 amps, then stop. The maximum continuous current shouldn't exceed 80 percent of the breaker rating. That would be 12 amps for a 15 amp circuit.
If the GFI trips at sat 11 amps, just set your car to charge at 10 amps. This will be slow charging, and you won't be able to pre-heat, but it will work. I've had to do this when staying at an old house and using a long, undersize extension cord. I maxed out at 9 amps, but it worked.

While that is decent advice related to a different topic of long wiring runs or underbuilt circuits, it isn't related to this issue of the GFCI tripping because of the tiny amount of current used for the startup ground leakage test.

 

[Enz295]

@Enz295 , Here is another technique to try. You most likely have 15 amp circuits in the garage. Before plugging in, set the car to charge at 9 amps max. Then plug in. If your GFI doesn't trip after a few minutes, go to 10 amps. Keep doing this until you reach 12 amps, then stop. The maximum continuous current shouldn't exceed 80 percent of the breaker rating. That would be 12 amps for a 15 amp circuit.
If the GFI trips at sat 11 amps, just set your car to charge at 10 amps. This will be slow charging, and you won't be able to pre-heat, but it will work. I've had to do this when staying at an old house and using a long, undersize extension cord. I maxed out at 9 amps, but it worked.

nice idea. I can look into that indeed!
Thx

 

[Rocky_H]

nice idea. I can look into that indeed!
Thx

Uh...what? That has nothing to do with the issue you're experiencing. The charging current level has nothing to do with tripping the ground leakage protection of a GFCI outlet.

 

[vandacca]

Uh...what? That has nothing to do with the issue you're experiencing. The charging current level has nothing to do with tripping the ground leakage protection of a GFCI outlet.

Is it possible that the higher the current, the greater the leakage? If so, then lowering current may reduce leakage below the trigger current. I admit, it's a little disconcerting that there is leakage in the line somewhere.

 

[Brass Guy]

EVSE (UMC in this case) tests the ground to make sure it's wired, which trips the GFCI.
Don't use a ground fault protected outlet with an EVSE.
Lowering the charge current will not prevent testing the ground circuit.

 

[davewill]

EVSE (UMC in this case) tests the ground to make sure it's wired, which trips the GFCI.
Don't use a ground fault protected outlet with an EVSE.
Lowering the charge current will not prevent testing the ground circuit.

Honest guys, you can charge just fine with a GFCI outlet, you just need to make sure it's up to date and in good working order. Code requires GFCI in garages in most places, so in newer homes, it's all you're going to find. If the OP will just replace the tripping GFCI outlet with a new one, something a handy guy can do, his problems will almost certainly vanish.

 

[Brass Guy]

I just did a few searches. I found out most GFCI outlets trip at 5ma, but there are others that trip at higher currents.
It'd be nice to know just how much current the UMC is allowing to flow.
@davewill - are older GFCI outlets more sensitive than 5ma?

 

[d21mike]

I got my car from the factory and took a road trip home via my son's house. While there i tried to use the 110 outlet in his garage and the circuit breaker popped for every outlet in the garage. There was a Tesla Supercharger about 15 miles from his house so not a big deal. When I got home I tested a 110 in my garage for fun (I have a NEMA 14-50) and it worked fine. So something was strange with his 110 outlets in his garage is my guess. So maybe same as the OP.

 

[FlyF4]

I got my car from the factory and took a road trip home via my son's house. While there i tried to use the 110 outlet in his garage and the circuit breaker popped for every outlet in the garage. There was a Tesla Supercharger about 15 miles from his house so not a big deal. When I got home I tested a 110 in my garage for fun (I have a NEMA 14-50) and it worked fine. So something was strange with his 110 outlets in his garage is my guess. So maybe same as the OP.

Can you supply some more info? What amperage did you have set for destination charging in the display console? Did you try setting it at 10 amps and testing the charge?

 

[d21mike]

Can you supply some more info? What amperage did you have set for destination charging in the display console? Did you try setting it at 10 amps and testing the charge?

Sorry I do not remember. It was 9/28/2017 and I just got the car. I did not even know how to use the Tesla Supercharger (i.e. able to plug in but had issue with unplugging it until a nice Tesla User helped me). Did not even no about changing amps at the time. And when I plugged in at my house I did not do anything but just plug it in.

 

[davewill]

I got my car from the factory and took a road trip home via my son's house. While there i tried to use the 110 outlet in his garage and the circuit breaker popped for every outlet in the garage. There was a Tesla Supercharger about 15 miles from his house so not a big deal. When I got home I tested a 110 in my garage for fun (I have a NEMA 14-50) and it worked fine. So something was strange with his 110 outlets in his garage is my guess. So maybe same as the OP.

If by circuit breaker, you meant GFCI tripping then maybe yes. It's also possible that the circuit breaker IS the GFCI (it's not usual as it's inconvenient and more expensive), in which case the answer could also be yes. If it actually was the circuit breaker tripping and not a GFCI, then either your charging attempt overloaded the circuit, or there's something wrong with the wiring or the circuit breaker.

 

[davewill]

I just did a few searches. I found out most GFCI outlets trip at 5ma, but there are others that trip at higher currents.
It'd be nice to know just how much current the UMC is allowing to flow.
@davewill - are older GFCI outlets more sensitive than 5ma?

My understanding is that the problem is as much time before it trips as it is the current sensitivity. And that's as far as my understanding goes. Anyway, it's a cheap thing to try.

 

[mongo]

I just did a few searches. I found out most GFCI outlets trip at 5ma, but there are others that trip at higher currents.
It'd be nice to know just how much current the UMC is allowing to flow.
@davewill - are older GFCI outlets more sensitive than 5ma?

EVSE equipment can be CCID20 and allow 20mA of unbalanced current.
Normal GCFI should be 5ma (but tend to age and get trip happy [anecdotally]).
https://ewh.ieee.org/r6/scv/pses/ieee_scv_pses_jun10.pdf

 

[Rocky_H]

It seems a few things are continuing to spread out on this topic. Let’s see if we can collect some of the info back together.

First off, what does a GFCI do? Well, it’s to shut off circuits if you are holding an appliance while wet and are getting electrocuted. The process there is that electricity is flowing in one wire of the cord, but instead of going back through the other wire, it’s taking a shorter path through your wet body to ground somewhere else. That is Bad™. So a GFCI tests to see that the two wires have the same current between them. If current goes in one, but doesn’t come back out the other, it will trip.

The Tesla UMC when you initially plug it in, will run a ground check. A proper ground needs to be wire running back through the house to the electrical panel, where it is tied to the Neutral line there. So (theorizing here), I think the method is to measure the resistance between ground and neutral to see if it does sense an eventual connection farther back in the wiring. If there is no connection at all, the ground isn’t really connected at all, and it will show a red light on the UMC and not work. The GFCI problem is that when measuring the resistance between Ground and Neutral, you’re putting a tiny voltage on it to take that measurement. Well, the two wires the GFCI is checking is Hot and Neutral, so if it detects that tiny current in the Neutral wire, it can be fooled into thinking it’s the electrocution situation and shut off.

The point that @davewill is talking about is that decently made and modern GFCI outlets and breakers are supposed to not be so overly sensitive and have a little bit of acceptable margin in them, so the tiny bit of current from the Tesla UMC’s ground check shouldn’t set them off. But that can be a little hit or miss of how close to the specifications they are.

So…this is in an initial check when the UMC is plugged in and tests the circuit that you will find out about this GFCI thing, BEFORE you ever plug it into the car. The actual charging process pulls the same current through Hot and Neutral, so the GFCI is perfectly happy with that and won’t trip from the charging process. THEREFORE, it has nothing to do with the charging current setting, whether 5, 10, 12, 16, or whatever.

 

[Rocky_H]

EVSE equipment can be CCID20 and allow 20mA of unbalanced current.
Normal GCFI should be 5ma (but tend to age and get trip happy [anecdotally]).
https://ewh.ieee.org/r6/scv/pses/ieee_scv_pses_jun10.pdf

Well that is interesting. I just read that document, and I see that you're right about those specs. The charging cable can do a 20mA level for the ground fault test, but hardwired GFCI circuits in the house are supposed to allow up to only 5mA. I'm kind of confused now why the test doesn't always trip every GFCI circuit.

 

[mongo]

It seems a few things are continuing to spread out on this topic. Let’s see if we can collect some of the info back together.

First off, what does a GFCI do? Well, it’s to shut off circuits if you are holding an appliance while wet and are getting electrocuted. The process there is that electricity is flowing in one wire of the cord, but instead of going back through the other wire, it’s taking a shorter path through your wet body to ground somewhere else. That is Bad™. So a GFCI tests to see that the two wires have the same current between them. If current goes in one, but doesn’t come back out the other, it will trip.

The Tesla UMC when you initially plug it in, will run a ground check. A proper ground needs to be wire running back through the house to the electrical panel, where it is tied to the Neutral line there. So (theorizing here), I think the method is to measure the resistance between ground and neutral to see if it does sense an eventual connection farther back in the wiring. If there is no connection at all, the ground isn’t really connected at all, and it will show a red light on the UMC and not work. The GFCI problem is that when measuring the resistance between Ground and Neutral, you’re putting a tiny voltage on it to take that measurement. Well, the two wires the GFCI is checking is Hot and Neutral, so if it detects that tiny current in the Neutral wire, it can be fooled into thinking it’s the electrocution situation and shut off.

The point that @davewill is talking about is that decently made and modern GFCI outlets and breakers are supposed to not be so overly sensitive and have a little bit of acceptable margin in them, so the tiny bit of current from the Tesla UMC’s ground check shouldn’t set them off. But that can be a little hit or miss of how close to the specifications they are.

So…this is in an initial check when the UMC is plugged in and tests the circuit that you will find out about this GFCI thing, BEFORE you ever plug it into the car. The actual charging process pulls the same current through Hot and Neutral, so the GFCI is perfectly happy with that and won’t trip from the charging process. THEREFORE, it has nothing to do with the charging current setting, whether 5, 10, 12, 16, or whatever.

Nice write up.

Some other info
Charged EVs | The EVSE GMI circuit: Should the standards be changed?

EV chargers have filters (capacitance/ inductance with some referenced to ground), that can cause normal GFCIs to trip where there is no resistive fault. That is part of the reason for the 20mA limit for EVSE. The trip could happen when the chargers are connected internally.

General warning: A GFCI will not prevent you from getting electrocuted if you are isolated from ground i.e. touching both wires and being part of the circuit.

 

[mongo]

Well that is interesting. I just read that document, and I see that you're right about those specs. The charging cable can do a 20mA level for the ground fault test, but hardwired GFCI circuits in the house are supposed to allow up to only 5mA. I'm kind of confused now why the test doesn't always trip every GFCI circuit.

The ground test isn't done at 20mA. 20mA is the must trip imbalance level for the EVSE.

 

[Rocky_H]

The ground test isn't done at 20mA. 20mA is the must trip imbalance level for the EVSE.

Oh, that makes a lot more sense. It's referring to the equivalent GFCI functionality that an EVSE has to have in it. The ground test the UMC uses may only be 1-3mA or less, but apparently is close enough to outlets' 5mA level that they can get triggered if they are too twitchy.