Heat issue on the new Tesla Ver 3 wall connecter

[Gadget-X]

So I had my connector put in per instruction with the charger. 60 Amp breaker and 18 ft of 6 gauge copper wire. Well I started a charge at 60 amp setting on the Tesla wall adapter and 1 hour or two later I felt the 60amp circuit breaker and it was very warm. I later measured it and it stats out around 76 deg and has one as high as 113 deg. I asked my electrician back over and he confirmed that he thought is was higher than he liked. He measured the AMPs on the line and it was exactly 48A at 241 volts. So I then dialed back the AMPs to 40 on the wall connector and it was max temp of 89 deg.

Has anyone installed the new Ver 3 Connector? Any thoughts on why the 60amp running at 80% is getting so hot? The electrician said he can not install on an 80 amp breaker by code unless the connector requires it.

Any thoughts?

 

[GWord]

Are your temps in C? Loose termination at the breaker can cause heat build up. Is your 6awg wire individual conductors or NM type cable like Romex?

 

[Gadget-X]

Fahrenheit. He used Romex to go thru wall to box mounted on inside of garage and 15 ft of copper stranded 6 gauge wire all three leads in conduit to Tesla connector. Yes he check the torque of all lugs.

Thanks for the reply

M

 

[yerEVan]

I had a similar problem with V2 wall charger. Temps were way high at the conduit terminating into the WC and also at the breaker. The breaker was very old. Ran to Home Depot and got a brand new 60amp, and temps went down about 30F. I have not noticed it getting that hot anymore.

 

[ShawnA]

Hi Gadget,

Your thread title and descriptions are confusing.
A Gen 3 wall charger will only deliver 48 Amps at 240 Volts....
Are you having trouble with a Gen 2 charger that prompts your question
about a Gen 3 charger???

Just Asking,

Shawn

 

[Gadget-X]

The Gen 3 that only delivers 48A (newest one). It says to install on 60 AMP breaker.

M

 

[GWord]

Fahrenheit. He used Romex to go thru wall to box mounted on inside of garage and 15 ft of copper stranded 6 gauge wire all three leads in conduit to Tesla connector. Yes he check the torque of all lugs.

Thanks for the reply

M

Some heat build up at the breaker is expected with large, continuous amp draws. The breaker is likely rated for 75degC. The voltage drop on your short run is probably between .5 and 1V. That will produce a a few dozen watts of heating in the branch.

 

[Gadget-X]

I had a similar problem with V2 wall charger. Temps were way high at the conduit terminating into the WC and also at the breaker. The breaker was very old. Ran to Home Depot and got a brand new 60amp, and temps went down about 30F. I have not noticed it getting that hot anymore.

What kind of temps were you getting before and after? I guess I could another new breaker

M

 

[ShawnA]

Hi Gadget-X,

Thank you for your answer...
I downloaded and read the Gen 3 install manual...
It is different from the Gen 1 and Gen 2 wall connectors.
In Gen 1 and Gen 2 the choice you make with the DIP switches is for the DELIVERED amperage...
For the Gen3 your choice by your phone or tablet is the SUPPLIED amperage breaker.

So you are correctly set for 60 amp breaker for 48 amp delivery to the car.
His readings confirm the 48 Amp delivery to the car.
That being said 113 F is not extraordinarily hot... BUT
There may be a weak link in the system - The Romex...
The Romex must also be 6 gauge or larger (smaller number).
If the Romex is the usual 10, 12, or 14 gauge this will cause resistance and HEAT...

Double check that the Romex is 6 gauge or larger...

Many people over the years on Gen 1 and Gen 2 have used a lower setting than maximum
to avoid the heat and strain on the system...

If the Romex is indeed 6 gauge or larger there may be a poor connection where
the Romex is bonded to the 6 gauge wire for your long run...
Please have the electrician confirm the Romex size and possible heat at the junction box.

Good luck,

Shawn

 

[ShawnA]

Hi Gadget-X,

Thank you for your answer...
I downloaded and read the Gen 3 install manual...
It is different from the Gen 1 and Gen 2 wall connectors.
In Gen 1 and Gen 2 the choice you make with the DIP switches is for the DELIVERED amperage...
For the Gen3 your choice by your phone or tablet is the SUPPLIED amperage breaker.

So you are correctly set for 60 amp breaker for 48 amp delivery to the car.
His readings confirm the 48 Amp delivery to the car.
That being said 113 F is not extraordinarily hot... BUT
There may be a weak link in the system - The Romex...
The Romex must also be 6 gauge or larger (smaller number).
If the Romex is the usual 10, 12, or 14 gauge this will cause resistance and HEAT...

Double check that the Romex is 6 gauge or larger...

Many people over the years on Gen 1 and Gen 2 have used a lower setting than maximum
to avoid the heat and strain on the system...

If the Romex is indeed 6 gauge or larger there may be a poor connection where
the Romex is bonded to the 6 gauge wire for your long run...
Please have the electrician confirm the Romex size and possible heat at the junction box.

Good luck,

Shawn

 

[Gadget-X]

It is 6 gauge for sure. Was hard to find but my electrician finally found some. It is code for running wire inside wall here is what I was told. I wanted 4 gauge but no romex to be found in 4 gauge.

Well my breaker at 113 F is within specs that I found. Thanks GWord !

 

[Nakk]

So I had my connector put in per instruction with the charger. 60 Amp breaker and 18 ft of 6 gauge copper wire. Well I started a charge at 60 amp setting on the Tesla wall adapter and 1 hour or two later I felt the 60amp circuit breaker and it was very warm. I later measured it and it stats out around 76 deg and has one as high as 113 deg. I asked my electrician back over and he confirmed that he thought is was higher than he liked. He measured the AMPs on the line and it was exactly 48A at 241 volts. So I then dialed back the AMPs to 40 on the wall connector and it was max temp of 89 deg.

Has anyone installed the new Ver 3 Connector? Any thoughts on why the 60amp running at 80% is getting so hot? The electrician said he can not install on an 80 amp breaker by code unless the connector requires it.

Any thoughts?

If I remember my basic electrical correctly, a breaker is rated for 90F above ambient temperature or 185F max. If it feels hot to the touch, though, I'd check it out. Warm is not bad. Hot is.

So what's getting warm is your circuit breaker? Correct? If so, it's nothing to do with the charger. The issue is with the circuit breaker or with the connection from the cable to the circuit breaker, or the wire itself. So... Check that the wire is indeed 6 gauge copper wire. Using an infrared thermometer check the temp of the cable at different spots and the breaker. If the breaker is warmer it's not your wiring. If the breaker is too hot there are two possibilities: either your breaker is bad or the wire was severely nicked when it was stripped to make the connection. I've seen this happen for a variety of reasons. If the wiring is severely nicked, you'll need to cut off that section and make a new connection. If you don't have enough slack, that run of wire will need to be replaced. If the wire is fine, replace the breaker. And your electrician is half right. Even if the charger requires more current, the wiring must be of sufficient gauge to support the circuit. An 80 amp breaker on 6 gauge copper is asking for a fire.

 

[Gadget-X]

Thanks. Yep I figured I was sticking with 60 amp for sure. I think the 80 amp for for the gen 2 charger, my confusion. I dropped the Tesla connector to 50 amp in the wifi settings. Temp is ~100 F. Been charging for 4 hours... I feel comfortable with this.

 

[Gadget-X]

Also the manual recommends no cutoff switch. Right now we have one at the box where the wiring comes into garage. I think I am going to have the electrician delete this... I read in the manual, "external disconnect switches are neither required nor recommended"

M

 

[ucmndd]

~115 F breaker temp under continuous 48A load is pretty normal.

 

[yerEVan]

What kind of temps were you getting before and after? I guess I could another new breaker

M

I should clarify, i didn’t have a problem with the V2 wall charger. I originally used that same older break with a very short Romex run, no heat issues that i noticed. Then i did it in conduit with the individual 6guage i think, and that’s when i noticed the cables very hot. I think at the breaker it was at least 130F. Maybe slightly more. We replaced the breaker and started charging again, and noticed the temp was much lower.

 

[Rocky_H]

Yeah, 100 or 115 degrees Fahrenheit isn't even really warm for a pretty high amp circuit like this--very normal. You should be able to tell the difference between if you put your hand on it and it feels obviously warm, but you can keep holding your skin on it, that's fine. But if it's like shocking, burn your fingers level, that's getting toward not OK.

OK, now I have a question here:

He used Romex to go thru wall to box mounted on inside of garage and 15 ft of copper stranded 6 gauge wire all three leads in conduit to Tesla connector.

I am curious on how this is handled by code. 6 gauge Romex is NOT allowed for a 60A circuit; it is only rated up to 55A. But 6 gauge individual wires in conduit IS rated high enough for a 60A circuit.

I don't quite know what the rule is if you are trying to split that between partly Romex and partly wire in conduit. Does it have to go with the lowest common denominator, and you have to go with the lowest rating? If so, 60A would not be allowed, and that would have to go to 50A. That would be my guess. Or maybe there is an allowance for a small portion of the run in Romex if the larger part is wire in conduit.

@eprosenx reads a lot of code stuff and may know the answer to this.

 

[Gadget-X]

Thanks. I will ask the electrician tonight when he comes by to take the cutoff switch out. Maybe Romex is the wrong type. Not a electrician. I did see that all the wires were the same size in the short piece thru the wall.

M

 

[Nakk]

I am curious on how this is handled by code. 6 gauge Romex is NOT allowed for a 60A circuit; it is only rated up to 55A. But 6 gauge individual wires in conduit IS rated high enough for a 60A circuit.

I don't quite know what the rule is if you are trying to split that between partly Romex and partly wire in conduit. Does it have to go with the lowest common denominator, and you have to go with the lowest rating? If so, 60A would not be allowed, and that would have to go to 50A. That would be my guess. Or maybe there is an allowance for a small portion of the run in Romex if the larger part is wire in conduit.

@eprosenx reads a lot of code stuff and may know the answer to this.

OK, don't take this as gospel, but I believe you can round up to the nearest circuit breaker when wiring an appliance that is self limited to 80% of the rated current. (Like a wall charger.) If you are wiring a box, like another circuit breaker panel, then you have to round down. That's what I remember, but code on that may have changed, or be different in different areas.

 

[eprosenx]

OK, now I have a question here:


I am curious on how this is handled by code. 6 gauge Romex is NOT allowed for a 60A circuit; it is only rated up to 55A. But 6 gauge individual wires in conduit IS rated high enough for a 60A circuit.

I don't quite know what the rule is if you are trying to split that between partly Romex and partly wire in conduit. Does it have to go with the lowest common denominator, and you have to go with the lowest rating? If so, 60A would not be allowed, and that would have to go to 50A. That would be my guess. Or maybe there is an allowance for a small portion of the run in Romex if the larger part is wire in conduit.

@eprosenx reads a lot of code stuff and may know the answer to this.

Yeah, lowest common denominator for sure.

OK, don't take this as gospel, but I believe you can round up to the nearest circuit breaker when wiring an appliance that is self limited to 80% of the rated current. (Like a wall charger.) If you are wiring a box, like another circuit breaker panel, then you have to round down. That's what I remember, but code on that may have changed, or be different in different areas.

I think you are referencing the “next size up” breaker rule.

While it sounds useful for wall connectors it never is. The reason is that the wall connector is only settable to limited steps that correspond with breaker sizes. So you set it to 48 amps on a 60a capable wire and breaker. On a 55a capable wire (like 6 gauge romex you have to set it to 40 amps since 48amps would be too high for the wire). At that point you may as well use a 50a breaker. (But legally I think you could use a 60a breaker the way the rule reads, but there would be no point and it would just reduce safety slightly).

This *would* be useful if they let you set the wall connector to 44 amps. Then you could use a 60a breaker on 6 gauge romex and get every last bit of legal capacity out (assuming no other deration needed). I suspect the v3 wall connector could do this in software (does it?).

But I am guessing Tesla has no desire to run that close to the margins. Less house fires due to EV charging is good for business.