any reason why a new 12A outlet in a garage keeps tripping, and why is my Amps keep changing after supercharging

[@heist80]

i got a 2 part question about charging, appreciate any experiences and advice

the last almost 3 years have been using regular 12A outlet to charge, yeah its slow but it has worked. had to change my GFCI once due to rain getting in to the outlet and/or the thing being very very old. covered up the outlet and no problems since

a week ago i moved into a brand new home with 4 plugs in the garage plus 2 plugs outside. first day i moved into my brand new home, plugged in my model 3 and no problems. charged it for hours in a regular outlet 12A. was thinking i'm home free

next day went to supercharge. then came home and plugged it up and the GFCI started to trip on every plug in the garage. tried it 5x and kept tripping. i gave up and decided to call an electrician or consider getting a wall charger.

next day came on here and did some research and checked my app. figured out the problem thanks to other threads, for whatever reason when i supercharged it changed the amps to a high number so i reduced it to 5 amps and hooked it up and no more tripping. i raised it from there up to 12A and i was good to go. was getting a decent 6mph charge just like my last place.

no problems for a few days then last night i hooked it up to charge before bed. woke up this morning and the car hadn't charged much. checked my outlet and GFI had tripped again, so i clicked it back on and charged for an hour with no problems.

so based on that 2 questions:

1. why did my ampage change after i supercharged, it has always adjusted on its own without me having to do it manually
2. why is this GFI tripped again after working fine for almost a week

last night i did use my oven which had an air fryer. did this maybe cause the garage GFI to trip due to overload? or maybe just a coincidence.
electricians in my experience are extreme liars so i don't trust them to come out and be honest with me so any advice or tips before i call one would be nice

 

[jjrandorin]

Likely because that outlet is shared with other devices (like virtually all standard home outlets are unless code mandates they not be shared, like a microwave).

What worked at your previous home in relation to charging off a standard outlet isnt relevant because it likely has different devices shared. Code states that EV charging is supposed to be an outlet thats not shared, due to an abundance of caution. Whether the oven matters or not would depend on if its an electric oven (and by code should have its own circuit) or natural gas, or if you were using a countertop airfryer that happened to be on the same circuit etc.

TL; DR - you should get a dedicated outlet to charge. It does not have to be 60amp, or 50amp, etc. You could even get a dedicated 20amp 240v outlet, since it sounds like your normal usage will be fine with that speed of charge.

If you are dead set on charging on that 12v outlet, you need to know what else is on it, so you know NOT to use anything on that outlet when you charge.

As to "why did the amps change?" I have no idea. I just know its not a good idea to depend on the car to set amps, that should be done automatically by the device you are using to charge.

 

[Cosmacelf]

i got a 2 part question about charging, appreciate any experiences and advice

the last almost 3 years have been using regular 12A outlet to charge, yeah its slow but it has worked. had to change my GFCI once due to rain getting in to the outlet and/or the thing being very very old. covered up the outlet and no problems since

a week ago i moved into a brand new home with 4 plugs in the garage plus 2 plugs outside. first day i moved into my brand new home, plugged in my model 3 and no problems. charged it for hours in a regular outlet 12A. was thinking i'm home free

next day went to supercharge. then came home and plugged it up and the GFCI started to trip on every plug in the garage. tried it 5x and kept tripping. i gave up and decided to call an electrician or consider getting a wall charger.

next day came on here and did some research and checked my app. figured out the problem thanks to other threads, for whatever reason when i supercharged it changed the amps to a high number so i reduced it to 5 amps and hooked it up and no more tripping. i raised it from there up to 12A and i was good to go. was getting a decent 6mph charge just like my last place.

no problems for a few days then last night i hooked it up to charge before bed. woke up this morning and the car hadn't charged much. checked my outlet and GFI had tripped again, so i clicked it back on and charged for an hour with no problems.

so based on that 2 questions:

1. why did my ampage change after i supercharged, it has always adjusted on its own without me having to do it manually
2. why is this GFI tripped again after working fine for almost a week

last night i did use my oven which had an air fryer. did this maybe cause the garage GFI to trip due to overload? or maybe just a coincidence.
electricians in my experience are extreme liars so i don't trust them to come out and be honest with me so any advice or tips before i call one would be nice

What device are you using to charge? The Tesla mobile connector with the NEMA 5-15 adapter?

While the home might be brand new, it doesn't mean the GFCI isn't faulty. I would suspect the GFCI is faulty and should be replaced.

Note that charging at 12A/120V is really inefficient. You are wasting energy when doing that. I would recommend installing a Wall Connector if at all possible now that you've moved into a new home.

 

[@heist80]

i'm using the tesla mobile connector

 

[Cosmacelf]

i'm using the tesla mobile connector

And you're using it just with the Tesla 5-15 adapter? Not a different adapter with another chained adapter?

 

[BobHinden]

Might be the GFCI being faulty. They have a history being too sensitive.

I agree with others that you would be better off with a dedicated circuit.

 

[drtimhill]

What device are you using to charge? The Tesla mobile connector with the NEMA 5-15 adapter?

While the home might be brand new, it doesn't mean the GFCI isn't faulty. I would suspect the GFCI is faulty and should be replaced.

Note that charging at 12A/120V is really inefficient. You are wasting energy when doing that. I would recommend installing a Wall Connector if at all possible now that you've moved into a new home.

+1 to that .. there is a fixed power draw the car uses during charging (that doesnt contribute to the charge). The lower the charge power, the greater percentage is being lost to that vampire drain .. and the more it costs you to charge the car.

 

[ewoodrick]

The GFCI is evidently having issues. This is not uncommon. The equipment that installers often put into new houses is far from quality equipment.

Also, is ANYTHING else plugged into any of the other plugs? They could be contributing to the problem.

A GFCI can trip for a variety of reasons, one of which is can be overcurrent, others being their main duty and a fault to ground. If something else tended to kick the breaker, then it does sound like actually ground fault leakage could be the culprit. (hence the make sure that nothing else is plugged into those outlets.

 

[E90alex]

Also, is ANYTHING else plugged into any of the other plugs? They could be contributing to the problem.

Also lights and garage door openers etc may be on the same circuit as the garage wall outlets. Possibly even shared with outside outlets/lighting or another room adjacent to the garage.

 

[DuncanM]

+1 to that .. there is a fixed power draw the car uses during charging (that doesnt contribute to the charge). The lower the charge power, the greater percentage is being lost to that vampire drain .. and the more it costs you to charge the car.

How many years of 'inefficient' charging will it take before it equals the installation cost of a dedicated 240V line, breaker and Tesla WC?

 

[@heist80]

yes i get it is way better then put in a wall charger, but what if you are renting and don't own your home? a lot of times its not so simple as putting in what you want. a lot of us aren't wealthy homeowners living in the suburbs, we live in cities where renting is a far superior option than owning. does this disqualify a person unless you live in a big home in the suburbs with a garage? some of us gotta do it this way for the time being. for almost 3 years i used an extension cord and plugged up to an outdoor plug, i don't see the big deal.

 

[Cosmacelf]

yes i get it is way better then put in a wall charger, but what if you are renting and don't own your home? a lot of times its not so simple as putting in what you want. a lot of us aren't wealthy homeowners living in the suburbs, we live in cities where renting is a far superior option than owning. does this disqualify a person unless you live in a big home in the suburbs with a garage? some of us gotta do it this way for the time being. for almost 3 years i used an extension cord and plugged up to an outdoor plug, i don't see the big deal.

Dude, you asked for recommendations. Don’t be defensive over suggestions. If the advice doesn’t apply to you, don’t take it.

If the house is a new house, chances are the garage GFCI you want to charge from is on a 20A breaker instead of a 15A breaker. If that is true, you can swap out the 15A GFCI (which is probably bad anyways) for a 20A GFCI receptacle, and use the Tesla 5-20 adapter which will end up giving you around 42% more charge going into your vehicle (16A vs 12A plus less overhead losses).

 

[3sr+buyer]

Likely because that outlet is shared with other devices (like virtually all standard home outlets are unless code mandates they not be shared, like a microwave).

The newest electrical codes specify that garages have a dedicated 120V 20A outlet for each parking space, presumably so that someone charging an EV on it will not encounter the problem of other stuff on the same circuit causing the circuit to be overloaded while charging an EV.

However, most existing houses and their garages are not new enough to have been built under this requirement.

Code Requirements for Garage Electrical Outlets

Whether you are building a new house, a new garage or simply remodeling the current garage you have, there are certain electrical codes you will need to adhere to. The good news is there is a governing body in the United States, the National Electrical Code (NEC), which creates these codes. We...

myperfectgarage.com

 

[Cosmacelf]

The newest electrical codes specify that garages have a dedicated 120V 20A outlet for each parking space, presumably so that someone charging an EV on it will not encounter the problem of other stuff on the same circuit causing the circuit to be overloaded while charging an EV.

However, most existing houses and their garages are not new enough to have been built under this requirement.

Code Requirements for Garage Electrical Outlets

Whether you are building a new house, a new garage or simply remodeling the current garage you have, there are certain electrical codes you will need to adhere to. The good news is there is a governing body in the United States, the National Electrical Code (NEC), which creates these codes. We...

myperfectgarage.com

Interesting. Such a circuit could also be used by block heaters for ICE vehicles in the winter as well. Another interesting thing about a dedicated 20A/120V circuit supplying one receptacle is that it is easy to change it into a 20A/240V circuit without needing to rewire.

 

[blackT3$!@]

2. why is this GFI tripped again after working fine for almost a week

I had similar issues with my new home GFI outlets. One issue was resolved by having the builder's electrician return and tighten all the electrical wiring in the circuit breaker box. The other issue was lightning storms here in NWF. Occasionally a distant lighting strike would trip the external GFI's in my garage, laundry room and both outside outlets because they are on the same circuit. I had an electrician install a dedicated 60amp circuit breaker and Tesla Wall Charger in my garage. I have never had any charging issues with this setup.

 

[@heist80]

thanks for the tips.

it MAY have been a lightning strike or something that happened that night. i will call an electrician if it happens again

 

[Rocky_H]

1. why did my ampage change after i supercharged, it has always adjusted on its own without me having to do it manually

I would think because coincidences happen in the universe.

2. why is this GFI tripped again after working fine for almost a week

Because GFCIs are notoriously finnicky, uptight, nervous little buggers like a chihuahua on amphetamines. They drift out of spec after a few years, so nuisance trips are common.

But there's one other factor with the charging connectors that makes this more of an issue. The Tesla mobile connector runs a test on the ground pin to make sure it's tied down and not floating. It runs a tiny bit of current from one of the hot pins onto the ground pin and sees if it seems to be resisted by being held to 0V. Fine. But that is exactly the thing a GFCI is supposed to detect and prevent. If current leaves one hot pin and isn't all immediately returning through the other hot pin, that would be the sign like a person touched the pin, and the current is going through their body and into the floor. That's why it needs to trip.

But ideally, the tiny current the Tesla mobile connector is using for that test is less than the tiny threshold the GFCI is looking for. It doesn't always work out that way. If the GFCI is old and out of spec, it may trip too often from that. And turning down the current draw isn't usually related to dealing with that.

So that is one of the reasons why just using a wall connector is a common recommendation now. It's hard wired and not on an outlet and doesn't have these GFCI problems. Sorry, it's just a frustration using outlets for this stuff. But as @Cosmacelf mentioned, replacing old GFCI outlets with new ones can sometimes resolve this.

 

[ewoodrick]

How many years of 'inefficient' charging will it take before it equals the installation cost of a dedicated 240V line, breaker and Tesla WC?

I haven't done the numbers, but an educated guess is probably thousands of days. The inefficiencies aren't that bad. They may even be less than your water heater inefficiencies.

 

[ewoodrick]

Interesting. Such a circuit could also be used by block heaters for ICE vehicles in the winter as well. Another interesting thing about a dedicated 20A/120V circuit supplying one receptacle is that it is easy to change it into a 20A/240V circuit without needing to rewire.

And could easily cost thousands of dollars.

 

[DuncanM]

The GFCI outlets in our AZ garage are fed via a 20amp 120v breaker. I changed the master GFCI outlet to a NEMA 5-20 GFCI for just a few dollars, and I used that outlet for a couple of months, to charge my M3 at 16A/120v. I then got around to installing a 20A 240v breaker into the garage subpanel and then added at dedicated NEMA 6-20 outlet. Total cost of parts was about $70.