Temp Rise in plug, outlet, cords, etc.

[Allistah]

Hey all --

We just got our M3 a week ago. I got the 14-50 outlet installed on Thursday and have some questions regarding the temp rises I'm seeing while charging at 40 amps.

We live in the Central Valley in CA so it gets warm here fairly often. Here are the specs of my install:

• Tesla Gen 2 HPWC
  
• 50 Amp, 2 pole breaker
  
• 6/3 w/ground stranded wire
• Run Length ~44 ft
  
• Leviton 14-15 outlet
• Voltage at breaker - 242.1v
• Voltage at outlet - 241.9v (0.2v drop, without any load)
• Voltage at breaker with charging at 40A - 235.2v
• Car reports voltage as 230v while charging
• Measured 41.3A and 41.8A draw at breaker (claw amp meter) while charging at 40A

After charging for a couple of hours last night with the garage around 95F, the back of the plug that is inserted into the outlet was 117F. (22F rise in temp from ambient). Does that sound reasonable? I wasn't sure so I shut it down to do more research. The cord to the HPWC and the 24' cord to the car was also fairly warm but not 117F warm - I forgot to measure it.

This morning I did another test:

Starting Temps:

• Breaker temp - 68F (outside)
• Garage temp - 79F
• Plug back temp - 80F

After 30 Minutes Temps:

• Breaker temp - 95F (+27F rise)
• Garage temp - 79F (Same)
• Plug back temp 97F (+17F rise)

Any thoughts on any of this? After doing some research, I'm going to buy the Hubbell 14-50 outlet and yank out that cheap Leviton. Also, I just bought a 4' 14-50 power cord for a stove/range to connect to the Tesla HPWC. Is there another cord that would be heavier duty that I should have got?

Also, should I install ferrules on the ends of these 6ga wires at both ends to ensure maximum connectivity? I noticed that they use them in the Tesla HPWC backing part that allows cord to come up from above.

Any info and/or suggestions would be appreciated. I absolutely do not want to have any smoke or melted wires anywhere - especially if the garage is up around 100F or something.

Thanks,

-Alli

 

[VT_EE]

That is also my experience with a hardwired HPWC. At 40 amps the breaker and romex get quite warm. Not hot enough to burn your hand, but in line with what you are describing.

 

[mswlogo]

UMC Gen 2 can’t pull 40A. Should be 32A max.

Keep in mind that most claw type amp meters don’t do the Power Factor correction. If the meter does not offer a PF scale, then it probably does not account for it. You’ll get an erroneous reading without that.

That said, the PF on the Tesla charging is usually high (close to 1.0) if I recall correctly.

Nothing should be “hot”, little warm is ok.

Should have GFCI breaker. Most folks don’t care for cheap Leviton outlets and go for bubble or similar instead.

What does the car say your pulling for amps?

 

[jjrandorin]

UMC Gen 2 can’t pull 40A. Should be 32A max.

Keep in mind that most claw type amp meters don’t do the Power Factor correction. If the meter does not offer a PF scale, then it probably does not account for it. You’ll get an erroneous reading without that.

That said, the PF on the Tesla charging is usually high (close to 1.0) if I recall correctly.

Nothing should be “hot”, little warm is ok.

Should have GFCI breaker. Most folks don’t care for cheap Leviton outlets and go for bubble or similar instead.

What does the car say your pulling for amps?

OP mentions using an HPWC though, which it sounds like OP converted to 14-50 instead of using it hard wired directly. Unless someone has another EV type / brand, I am not sure why people make that choice, but they do.

 

[Eno Deb]

I'm assuming you are talking about the "Corded Wall Connector" with 14-50 plug. The plug getting warm is normal, but it should not be too hot to touch. You should not use an extension cord at this kind of ampacity. It defeats the inbuilt temperature monitoring in the Wall Connector's plug, and adds another contact surface where some energy will be lost (and turned into heat). If you feel it gets too warm, reduce the charge power in the car.

If you are using the regular Wall Connector (without 14-50 plug) you should wire it directly instead of using a 14-50 plug/outlet.

 

[brkaus]

Which range 14-50 cord do you have? A good number of them are designed for 40a as stoves don’t draw that much current and are not a continuous load.

 

[ewoodrick]

That's completely normal.

5V drop @40A is 200 watts of heat generated.

To minimize the voltage drop, a larger diameter wire will be needed and that, especially in the UMC, makes the cord larger and less flexible, and a lot more expensive. So it's a common trade-off. If it's warm, it is quite okay.

 

[mswlogo]

OP mentions using an HPWC though, which it sounds like OP converted to 14-50 instead of using it hard wired directly. Unless someone has another EV type / brand, I am not sure why people make that choice, but they do.

I think @Eno Deb figures it out and agree with his advice.

 

[Allistah]

First I want to thank those who replied - really appreciate you taking the time.

I just ordered the Hubbell HBL9450A outlet from Amazon for $75. Will be here later today.

To answer the questions above:
1) I chose the 14-50 style outlet because I will also be using it to plug in our 5th wheel which makes use of the 14-50 plug. It actually uses the center neutral and the two 120v sides independently to power each of the AC units on the trailer. This makes even more reason to get the Hubbell since I will at times unplug/plug things into it.

2) This is a Tesla Gen 2 wall mount charger. I'm not using the charger that comes with the car. I have it set to "8" inside for 40A draw on a 50A breaker. Car reports pulling at 40A. Claw amp meter at the breaker reports 41.3A and 41.8A on each line while charging at 40A.

Is there a better plug to go from the 14-50 outlet to the HPWC? I want to make sure I'm doing everything well, I don't want any problems.

Should I install ferrules on the ends of the 6 gauge wires? I noticed that Tesla uses them on their wires in the HPWC.

 

[TexasEV]

There’s a contradiction in the original post. You say it’s a 14-50 outlet, but then say you’re using a HPWC. The HPWC (now just called Wall Connector) is designed to be hard wired.

Edit- never mind. all the above posts came while I was typing mine. But a small correction— you are using the charger that comes with the car, as the charger is IN the car. The UMC and HPWC are Connectors, or EVSEs, not chargers.

 

[brkaus]

My breaker doesn’t heat up that much. I have 6/3 solid Romex. Breaker connection torqued properly? Is the breaker rated for the wire type?

Properly crimped ferrules help the connection, esp on larger wire. but doubt they are necessary.

I am not an electrician.

 

[TexasEV]

I'm assuming you are talking about the "Corded Wall Connector" with 14-50 plug.

No such thing as a “Corded Wall Connector”. It was a “Corded Mobile Connector” ( or Non-universal Mobile Connector as it was nicknamed).

 

[Eno Deb]

No such thing as a “Corded Wall Connector”. It was a “Corded Mobile Connector” ( or Non-universal Mobile Connector as it was nicknamed).

The official name in the store is actually "Wall Connector with 14-50 Plug".

 

[jjrandorin]

Actually, tesla makes a HPWC with the 14-50 on it. Others have linked to it in the past. It goes in and out of stock, but they do make one. With that being said, this OP mentions that he used:

===========================

Also, I just bought a 4' 14-50 power cord for a stove/range to connect to the Tesla HPWC. Is there another cord that would be heavier duty that I should have got?

===========================

In the first post, so he wired that part himself. Given the level of detail in the first post, and the fact that OP owns equipment to test for power etc, I am going to make an assumption that the OP has some level of comfort around electrical wiring.

OP, understand now why you wanted the 14-50. I dont have the level of skill electically as many here, so cant comment on your questions other than to say I would recommend swapping out the leviton like you planned on doing, and re checking to make sure you dont have any cables shorting / touching. Warm is ok, but "hot" isnt is my understanding, but those are very subjective terms

 

[mswlogo]

First I want to thank those who replied - really appreciate you taking the time.

I just ordered the Hubbell HBL9450A outlet from Amazon for $75. Will be here later today.

To answer the questions above:
1) I chose the 14-50 style outlet because I will also be using it to plug in our 5th wheel which makes use of the 14-50 plug. It actually uses the center neutral and the two 120v sides independently to power each of the AC units on the trailer. This makes even more reason to get the Hubbell since I will at times unplug/plug things into it.

2) This is a Tesla Gen 2 wall mount charger. I'm not using the charger that comes with the car. I have it set to "8" inside for 40A draw on a 50A breaker. Car reports pulling at 40A. Claw amp meter at the breaker reports 41.3A and 41.8A on each line while charging at 40A.

Is there a better plug to go from the 14-50 outlet to the HPWC? I want to make sure I'm doing everything well, I don't want any problems.

Should I install ferrules on the ends of the 6 gauge wires? I noticed that Tesla uses them on their wires in the HPWC.

The ferrules are on stranded wire that you are referring to, you are on solid wire and won’t help and probably make things worse.

I’d seriously consider making the breaker a GFCI, if not already, for your application.

Breakers can get a little warm. Not sure what a reasonable temp is though.

 

[Allistah]

The wire I installed is 6 gauge, stranded. I didn't like to learn that the Leviton's clamp mechanism would spread the strands out, thus making a poorer connection that it could have. I also read that the Hubbell outlet has a clamp style mechanism which will keep all the strands together. Will see when it arrives later today. Since my 6ga wire is stranded, that's why I was asking about adding ferrules to the ends.

I am comfortable about working with the power and such, I've just never done anything that requires so much current. I do know that if you don't do things right and things are under-rated for what they should be, you can be setting yourself up for a big problem which is what prompted the original post.

 

[Allistah]

The official name in the store is actually "Wall Connector with 14-50 Plug".

Thanks for the correction, appreciate it. Drives me crazy when people don't use the right terms so thanks again.

 

[Sophias_dad]

First I want to thank those who replied - really appreciate you taking the time.

I just ordered the Hubbell HBL9450A outlet from Amazon for $75. Will be here later today.

To answer the questions above:
1) I chose the 14-50 style outlet because I will also be using it to plug in our 5th wheel which makes use of the 14-50 plug. It actually uses the center neutral and the two 120v sides independently to power each of the AC units on the trailer. This makes even more reason to get the Hubbell since I will at times unplug/plug things into it.

2) This is a Tesla Gen 2 wall mount charger. I'm not using the charger that comes with the car. I have it set to "8" inside for 40A draw on a 50A breaker. Car reports pulling at 40A. Claw amp meter at the breaker reports 41.3A and 41.8A on each line while charging at 40A.

Is there a better plug to go from the 14-50 outlet to the HPWC? I want to make sure I'm doing everything well, I don't want any problems.

Should I install ferrules on the ends of the 6 gauge wires? I noticed that Tesla uses them on their wires in the HPWC.

I used ferrules on my 6AWG stranded for my HPWC install, its a great idea, although I'm not sure how many times I'll need the tool.

Sounds like the Hubbell outlet is already pretty good for stranded wire... I might skip the ferrules.

 

[Allistah]

Yeah, I'm going to wait for the ferrules until I see the outlet. I'll post some pics when I get it later today/this evening.

I did however go out and took a picture of under the side of the breaker and found the torque specs for it. 6 gauge wire should be torqued to 40 inch pounds. Got the torque wrench out, breaker off, verified no voltage w/DMM on both breaker screw heads, gloves on and I found that they were not tightened enough the first time I installed the breaker to the proper torque. Guessing this will decrease the temp of the breaker. Screwed in maybe 1/2 to 3/4 turn additionally on each. Will check again the next time I charge to see if it heats up less (or more for that matter).

 

[VT_EE]

My breaker doesn’t heat up that much. I have 6/3 solid Romex. Breaker connection torqued properly? Is the breaker rated for the wire type?

Properly crimped ferrules help the connection, esp on larger wire. but doubt they are necessary.

I am not an electrician.

My breaker gets warm, but only after hours of 40amp charging. It’s about the same temp as the romex 6AWG gets.