Breaker tripping

[davewill]

What matters is what amperage is shown AFTER you plug in. Before you plug in, the car will show 48a as a max because it doesn't know what the amperage of the wall connector is.

 

[JoelCool]

Thanks guys. I tested today and first went in to my phone app and changed it from 48 to 40. Charged for 2.5 hours without tripping breaker. Although I did notice the breaker was pretty hot. An hour later went back into my app and it wants to start at 48. Assuming it's an app issue but now I know what to do (or not to do). Thanks for all your input! I have learned a bit about electricity but think I'll stay away from it as much as possible.

 

[ucmndd]

What matters is what amperage is shown AFTER you plug in. Before you plug in, the car will show 48a as a max because it doesn't know what the amperage of the wall connector is.

Exactly this. Major source of confusion and so few people understand it.

 

[jjrandorin]

Thanks guys. I tested today and first went in to my phone app and changed it from 48 to 40. Charged for 2.5 hours without tripping breaker. Although I did notice the breaker was pretty hot. An hour later went back into my app and it wants to start at 48. Assuming it's an app issue but now I know what to do (or not to do). Thanks for all your input! I have learned a bit about electricity but think I'll stay away from it as much as possible.

You shouldnt be able to charge at 48 amp at all if the wall connector is actually provisioned for 50amp like you say it is. it should say 40/40 after it starts charging. You want to check that again, and if its actually set for 50amp like you say it is, and trying to charge at 48amp like you say it is and you have to turn it down from the app, then there is an issue with the wall connector.

It would also be the only instance I have read of here with the wall connector being correctly provisioned for one setting but charging at a different one.

 

[Rocky_H]

I'm going to reiterate what a couple of people have said. Whatever amp level you see in your app or change it to in your app while the car is not plugged into anything yet means absolutely nothing at all. That will just let you dial the amps up and down based on the capacity of the onboard charger inside the car. It can't see anything about the charging equipment yet, and that WON'T be related to what the car will try to use when you then plug it in.

So when you plug the charging equipment into the car, that equipment will announce a signal to the car of how many amps it has available to provide. THEN you can get some relevant information. As @davewill mentioned, the car's charging screen and the charging screen in the app will show two numbers with a slash, like 40/40 or 48/48. At that point it is showing how much it is using out of how much the equipment says is available.

So then you get to see if the charging equipment is configured properly or not. If the number after the slash is 48, that is set up wrong, and you need to reconfigure that wall connector. If it says 40 after the slash, then that is correct for a 50A circuit, and it's set correctly, but if it is still tripping the breaker for some reason, then yes, there is a hardware issue that needs to be investigated.

 

[JoelCool]

Tx for the feedback. I set it on the car and it does just that now. Everything good. Learning processes......

 

[davewill]

Tx for the feedback. I set it on the car and it does just that now. Everything good. Learning processes......

Not a good solution for a daily charging solution. The setting in the car is prone to being forgotten or ignored. Then you'll trip the breaker again. PLEASE, make the effort to correctly provision the wall connector so that you CAN'T charge at the wrong amperage.

 

[JoelCool]

Not a good solution for a daily charging solution. The setting in the car is prone to being forgotten or ignored. Then you'll trip the breaker again. PLEASE, make the effort to correctly provision the wall connector so that you CAN'T charge at the wrong amperage.

I have already gone through the provisioning and it was set correctly. As it is I'm no longer having any issue. Thanks for the feedback!

 

[arnolddeleon]

This post is posterity. The OP seems satisfied with their solution, this for others in the future reading this thread and their safety.

Quite likely the the HPWC is commissioned wrong or defective (or the car is defective) but the odds are with the HPWC. 99.99% of the people on this planet won't know how much current you are allowed to continuously from a 50A breaker per the NEC. An answer is that 100% wrong 48A. The fact the car sees a pilot signal that allows to happen is clear evidence of something being wrong.

I've never commissioned a HPWC, it's possible that the use interface is confusing. Some of EVSE require you to enter breaker size (in this case that would have been 50A). Other units require to enter maximum allowed charging current, in this case that would have been 40A. You have to be in 0.01% to know 40A is the correct answer for a 50A breaker. You can imagine how easily it would be to commission a system wrong if the user interface asked for the maximum charging current. Most people on the planet would look at the breaker and see that is says 50A so they will enter 50A. What makes this situation worse is that many cars can't charge about 32A so this installation error goes undetected until a car with higher charging capacity goes to use the station. Maybe someday local inspectors will test EVSE installations.

 

[Mrbrock]

There us something wrong. 8 gauge wire shouldn’t be installed in 1/2 emt. The evse isn’t commissioned for a 50 amp breaker, it is commissioned for a 60 amp breaker. You would need #6 thhn not 6/2 romex.

Once the breaker got heat soaked it was more likely yo trip. If you don’t use it for an hr and give it time to cool off You should be able to charge at 40 amps unless the electrician didn’t properly tighten the lugs in the breaker or your panels buss bar is damaged.

Really? You can run 2 6ga thhn and a 10ga thhn ground in 1/2 emt. Interestingly, you can't run just 2 6ga thhn but adding a third conductor allows you higher fill %.

You are allowed three 8 gauge THHN in 1/2” EMT, so there is nothing wrong with the choice of conduit if he used 8 gauge,

Echoing others who said the problem is that EVSE didn’t get commissioned properly. It needs to be commissioned via an app to set it to a 50A breaker installation.

Also echoing others who said the electrician probably screwed up by not using 6 gauge and a 60A breaker to maximize your charging speed.

I have already gone through the provisioning and it was set correctly. As it is I'm no longer having any issue. Thanks for the feedback!

If you have changed nothing on the HPWC then it is still incorrect as others have stated. Changing the settings in the car does not fix the issues with the HPWC. Can you post a picture of your screen while the car is charging at home? This will help to ensure the HPWC is working properly.

Here is the concern. With the car set at 48A and the HPWC attempting to charge at 48A, some issue is being magnified and causing the breaker to trip. Setting the car to 40A brings this issue to within spec and charging continues but there is still an issue that could cause problems in the future.

 

[NickFie]

I've never commissioned a HPWC, it's possible that the use interface is confusing.

I am reasonably confident that Tesla v3 HPWC (current model) setup dialog uses breaker rating. This information is easiest to find - it’s visible when you open the electrical panel door.

It’s also possible the electrician did the wireless setup for the customer and entered 60 Amps to allow the customer to get full value from their HPWC.

I’ve configured several v2 HPWC and a ChargePoint. They all use circuit breaker rating in setup. Physical dial in v2 HPWC, iPhone App for the ChargePoint.

In every case I had to tighten wire connections after the electrician left to reduce voltage drop and circuit breaker heat during full-capacity charging - 80 Amps for the v2’s; 48 Amps for the ChargePoint.

 

[howardnj]

Thanks everyone for the excellent feedback. I do have the electrician coming back out so I'll see what he says. He will double check all screws for tightness and bring a spare breaker. I went back through commissioning and it was/is set for 50 amp breaker so that part is good. I will set the phone app to 40 now and see what happens. I did see thhn on the wires in the panel but not sure if it's 8 or 6 but pretty sure it's 8. The conduit has 3 90 degree bends. Hopefully I'll post what fixes the issue.

Was your electrician licensed?
Do you have local codes for EV chargers?
Does your locality require a permit and inspection?
Would your homeowners insurance cover you if your home were set on fire due to an improper EV Charger installation with no permit?

 

[MattM24]

Really? You can run 2 6ga thhn and a 10ga thhn ground in 1/2 emt. Interestingly, you can't run just 2 6ga thhn but adding a third conductor allows you higher fill %.



If you have changed nothing on the HPWC then it is still incorrect as others have stated. Changing the settings in the car does not fix the issues with the HPWC. Can you post a picture of your screen while the car is charging at home? This will help to ensure the HPWC is working properly.

Here is the concern. With the car set at 48A and the HPWC attempting to charge at 48A, some issue is being magnified and causing the breaker to trip. Setting the car to 40A brings this issue to within spec and charging continues but there is still an issue that could cause problems in the future.

Regarding the 2 versus 3 conductor fill rates, it’s due to they shape of each conductor. The third fits in differently than the second.

Also, just because you can doesn’t mean you should. Electricians that pull wires all day will install wherever works best for them (above minimum allowed sizes). I.e. I have 1” EMT run to my 6awg R90 setup. There are a few bends in there.

 

[thefisch]

In very case I had to tighten wire connections after the electrician left to reduce voltage drop and circuit breaker heat during full-capacity charging - 80 Amps for the v2’s; 48 Amps for the ChargePoint.

I've been thinking about retightening the connections on my v2 WC. Curious as to what you saw with voltage and heat at breaker with your v2 chargers that prompted you to tighten the connections. My voltage hovers around 238v and I've gotten temps at the breaker of up to 127f in an enclosed garage with ambient temps in the high 80's. With garage open temps are about 10 degrees less thanks to airflow.

 

[NickFie]

I've been thinking about retightening the connections on my v2 WC.

I can’t remember the temperatures. I removed the panel cover; started car charging at full draw; waited 5 minutes then measured temperature with a probe. If it seemed high I stopped charging; turned off breaker and then tightened the connection.

Also check the connection at the HPWC end. Our daughter and her husband had to replace their v2 HPWC. The electrician’s “B Team” hadn’t tightened the termination to spec. They didn’t realize it, but over time the overheated connection fried the HPWC electronics.

 

[jeremymc7]

I can’t remember the temperatures. I removed the panel cover; started car charging at full draw; waited 5 minutes then measured temperature with a probe. If it seemed high I stopped charging; turned off breaker and then tightened the connection.

Also check the connection at the HPWC end. Our daughter and her husband had to replace their v2 HPWC. The electrician’s “B Team” hadn’t tightened the termination to spec. They didn’t realize it, but over time the overheated connection fried the HPWC electronics.

Did you have to get a replacement at your cost or was it covered by someone else.

 

[Mrbrock]

Regarding the 2 versus 3 conductor fill rates, it’s due to they shape of each conductor. The third fits in differently than the second.

Also, just because you can doesn’t mean you should. Electricians that pull wires all day will install wherever works best for them (above minimum allowed sizes). I.e. I have 1” EMT run to my 6awg R90 setup. There are a few bends in there.

What do you mean by the shape and the third fits in differently than the second? Are there conductors that aren’t round? And fill % is about cross section so the shape doesn’t matter. Whether a stranded wire is round or flattened oval, it’ll still have the same cross section a fill %. 2x 6ga thhn are going to fit the same way in 1/2 emt whether another conductor is there or not. Having a third conductor will help with pulling through bends but it doesn’t change the shape and fit of the 2x 6ga conductors.

 

[mswlogo]

The HPWC isn't commissioned properly. It shouldn't even be trying 48 amps. That said, it should be able to run at 48 amps for at least a little while(minutes) before the circuit breaker trips. You should not and can not rely on the car/app setting to keep the rate lower than 48 amps.

There is still a problem at the breaker. Either the breaker itself is defective or the connections are bad. Connection(s) because there's the obvious ones you screw in very tightly and the less obvious ones that clip onto the bus bars. When panels get old, their bus bars can get corroded and bad connections cause heat. Heat is one of the criteria that the breaker uses to trip.

It could run indefinitely at 48A and that’s the danger.

Nobody asked if the breaker is tripping on load or due to GFCI?

If it’s a Wall Connector it does not need a GFCI breaker.

If it’s tripping on load something is really messed up.

 

[mswlogo]

Tx for the feedback. I set it on the car and it does just that now. Everything good. Learning processes......

You should set everything to max and it should automatically switch to 40A when actually charging. If it doesn’t it’s not set up right. User should not be able to charge over the hard configured limit, ever if wall connector is set correctly.

 

[MattM24]

What do you mean by the shape and the third fits in differently than the second? Are there conductors that aren’t round? And fill % is about cross section so the shape doesn’t matter. Whether a stranded wire is round or flattened oval, it’ll still have the same cross section a fill %. 2x 6ga thhn are going to fit the same way in 1/2 emt whether another conductor is there or not. Having a third conductor will help with pulling through bends but it doesn’t change the shape and fit of the 2x 6ga conductors.

Wires are all round and so is the raceway.
Two round wires side by side can only fill a certain percentage before they get To tight to pull and risk damage.
When you introduce a third round wire, it goes into the empty space around the first two wires.