Upgrading from NEMA 14-50 50amps to HPWC 60amps

[jgd108]

Update after 2 hrs of charging: the pigtail is just warm, but the NEMA 14-50 outlet is quite hot and so is the first 6-8 inches of the conduit above the NEMA outlet. Almost smell something. Is that because of the 8 AWG cabling? I thought that was fine.. Seems like it's venting out the heat. I stopped the charging for the night.. @eprosenx

 

[eprosenx]

Understood. I splurged for safety sake and been charging for the past hour.
It was stuck at 36mph for a long time, now 37mph and the voltage is hovering between 234-237V is that because of the pigtail?
When I was doing UMC at 32 amps it used to be 240V.
Pigtail plug is warm but all good no overheating.

Add some pics of my install..

So that could be voltage fluctuation of the utility, though I suspect it may be more due to the fact that your wire back to the panel was 8 AWG right? So 8 awg in conduit has a max rating of 50a (40a continuous). I suspect that when running at that max load you are seeing higher voltage loss (but still well within spec).

It also could be the pigtail in part, but hopefully not if all your connections are tight.

 

[eprosenx]

Update after 2 hrs of charging: the pigtail is just warm, but the NEMA 14-50 outlet is quite hot and so is the first 6-8 inches of the conduit above the NEMA outlet. Almost smell something. Is that because of the 8 AWG cabling? I thought that was fine.. Seems like it's venting out the heat. I stopped the charging for the night.. @eprosenx

Hrm, that is not good. 8 AWG is fine as long as it is in conduit so that should not be the issue. My bet is that the wires into the back of the receptacle are not tight or the receptacle is damaged.

You reported an issue before with your UMC right of a "hot outlet"? That is one issue with the pigtail btw... The UMC has a safety feature built in that the wall connector does not when using a pigtail.

I would cut power to the circuit and take the receptacle out and inspect everything and tighten the terminals. If I had any concerns whatsoever I would replace the receptacle. If there are problems there you might find the insulation is melted off the 8 awg wire. This is the typical failure mode. If you have a poor connection it heats up and melts the insulation.

If this is the case, installing the HPWC did not cause the issue, but it would un-mask it since it draws 40a vs 32a.

 

[Glamisduner]

I feel your pain, I tried mine at partial peak, $.26 kWh for 2 hours charging period. Just want to be make sure, safe better than sorry! I don’t want to get smoked when I charge during sleep time.

peak at .26 isn't bad at all!

 

[jgd108]

Hrm, that is not good. 8 AWG is fine as long as it is in conduit so that should not be the issue. My bet is that the wires into the back of the receptacle are not tight or the receptacle is damaged.

You reported an issue before with your UMC right of a "hot outlet"? That is one issue with the pigtail btw... The UMC has a safety feature built in that the wall connector does not when using a pigtail.

I would cut power to the circuit and take the receptacle out and inspect everything and tighten the terminals. If I had any concerns whatsoever I would replace the receptacle. If there are problems there you might find the insulation is melted off the 8 awg wire. This is the typical failure mode. If you have a poor connection it heats up and melts the insulation.

If this is the case, installing the HPWC did not cause the issue, but it would un-mask it since it draws 40a vs 32a.

Thanks. In the case of the UMC being really hot I later found that it was mis-inserted so once I got it back in fully into the outlet it never got hot again. Which leads me to believe the outlet is fine, or at least good enough for 32 amps.

8AWG should indeed be within specs, thanks for confirming. So you def. believe it would be a wiring issue in the receptacle (damaged I doubt, it's only 3 months old with light use)?

I'm right now charging at 32A by setting it in the car, but not ideal (seems to reset to 40A and no control from phone app).

I have my solar install in a week with panel upgrade, or I can always ask my electrician who installed the outlet to come back and check it (he did send his apprentice to flip it for the ground, that could've have caused loose connections but UMC has been charging fine).

Few more thoughts.. since the pigtail is 6AWG for red and black, can it technically support 48A charging? Meaning if I decided to upgrade the conduit cabling to 6 AWG as well, and switch to a 60A breaker, the Wall Connector could do 48A or I'm missing something? I know the NEMA 14-50 would be at risk later but then I could change back to a 50A breaker if I sell the house.

Thanks! Hope to get this fixed soon.

 

[Vines]

Thanks. In the case of the UMC being really hot I later found that it was mis-inserted so once I got it back in fully into the outlet it never got hot again. Which leads me to believe the outlet is fine, or at least good enough for 32 amps.

8AWG should indeed be within specs, thanks for confirming. So you def. believe it would be a wiring issue in the receptacle (damaged I doubt, it's only 3 months old with light use)?

I'm right now charging at 32A by setting it in the car, but not ideal (seems to reset to 40A and no control from phone app).

I have my solar install in a week with panel upgrade, or I can always ask my electrician who installed the outlet to come back and check it (he did send his apprentice to flip it for the ground, that could've have caused loose connections but UMC has been charging fine).

Few more thoughts.. since the pigtail is 6AWG for red and black, can it technically support 48A charging? Meaning if I decided to upgrade the conduit cabling to 6 AWG as well, and switch to a 60A breaker, the Wall Connector could do 48A or I'm missing something? I know the NEMA 14-50 would be at risk later but then I could change back to a 50A breaker if I sell the house.

Thanks! Hope to get this fixed soon.

The NEMA 14-50 is rated for 40A continuous, I would not run more than 40A through one. We just replaced the solar on a customers garage where there was a fire due to an improper Car Charger installation. The PV panels were probably ok but the County made us replace them out of an abundance of caution.

 

[eprosenx]

The NEMA 14-50 is rated for 40A continuous, I would not run more than 40A through one. We just replaced the solar on a customers garage where there was a fire due to an improper Car Charger installation. The PV panels were probably ok but the County made us replace them out of an abundance of caution.

^--- What he said. A NEMA 14-50 is rated for 50 amps, which means 40 amps continuous. You need to hard wire into the HPWC if you want 60a. (48 continuous)

Also, it really is very simple to shut off that breaker and just pull out the receptacle and visually inspect it and tighten the connectors. I would not want to use that receptacle at all until I inspected it visually after it getting hot within its rated capacity. It should take about five minutes... (you don't have to disconnect any wires)

 

[DUBM3]

peak at .26 isn't bad at all!

Actually that’s the Partial Peak, my peak rate is $.47 kWh

 

[jgd108]

The NEMA 14-50 is rated for 40A continuous, I would not run more than 40A through one. We just replaced the solar on a customers garage where there was a fire due to an improper Car Charger installation. The PV panels were probably ok but the County made us replace them out of an abundance of caution.

^--- What he said. A NEMA 14-50 is rated for 50 amps, which means 40 amps continuous. You need to hard wire into the HPWC if you want 60a. (48 continuous)

Also, it really is very simple to shut off that breaker and just pull out the receptacle and visually inspect it and tighten the connectors. I would not want to use that receptacle at all until I inspected it visually after it getting hot within its rated capacity. It should take about five minutes... (you don't have to disconnect any wires)

Thanks guys. Last thing I want to do is start a fire (that too on my first electrical project!). Will turn off the breaker and open the receptacle and check the wiring if it's all well connected. Hopefully that's it. Will be back home in a week so will update then.

 

[jgd108]

Update for the benefits of others in the future.. check your NEMA outlet after installation by electrician!
It appears the red wire had it's jacket inserted into the plug and it had started to melt, which explains the hot feeling on the pipe just above the outlet, and the outlet itself! It became obvious when charging at 40amps.
Thanks to @eprosenx and others who suggested I do testing during day time and was able to catch that hazard.
The solar electrician when I showed him said I got lucky!

I decided to kill the outlet and do direct connect instead of pigtail (which I should've done before, but now I felt more confident!).
Bought EMT conduit, cut pieces and made a path from where the tubing ended to the Wall Connector, and painted it white.

The solar electrician helped me pull the new 6 AWG wires and I ran a new 10 AWG green wire, and removed the neutral white.
He also installed the 60 amps breaker (I bought the wrong type apparently, thank god I didn't install the breaker myself!).

The 24 feet of cabling wasn't fitting well with the conduit, so I re-installed my cable organizer below.

Please enjoy my personal journey from mobile connector, pigtail wall connector, to direct connect!

Learned a lot in the process )

 

[Vines]

Wow, crisis narrowly averted! Good job with following up.

 

[eprosenx]

Update for the benefits of others in the future.. check your NEMA outlet after installation by electrician!
It appears the red wire had it's jacket inserted into the plug and it had started to melt, which explains the hot feeling on the pipe just above the outlet, and the outlet itself! It became obvious when charging at 40amps.
Thanks to @eprosenx and others who suggested I do testing during day time and was able to catch that hazard.
The solar electrician when I showed him said I got lucky!

View attachment 338662

I decided to kill the outlet and do direct connect instead of pigtail (which I should've done before, but now I felt more confident!).
Bought EMT conduit, cut pieces and made a path from where the tubing ended to the Wall Connector, and painted it white.

The solar electrician helped me pull the new 6 AWG wires and I ran a new 10 AWG green wire, and removed the neutral white.
He also installed the 60 amps breaker (I bought the wrong type apparently, thank god I didn't install the breaker myself!).

The 24 feet of cabling wasn't fitting well with the conduit, so I re-installed my cable organizer below.

Please enjoy my personal journey from mobile connector, pigtail wall connector, to direct connect!

Learned a lot in the process )

View attachment 338664

Awesome! I am glad it all worked out for you! You have ended up with an excellent setup at what I think was a pretty cost effective price. So glad your house did not burn down. A great example of how even "professionals" make mistakes. Be vigilant.

Nice photo collage with the charging rates! I am going to keep a link to this post.

One comment: Tesla has the bracket that can go behind the Wall Connector for top conduit entry. This spaces the Wall Connector further away from the wall, so if you wanted to use the cord hanger on the Wall Connector you could potentially use that to create more space. But what you have works great!

 

[Glamisduner]

I thought you needed 4awg for the HPWC?

Also how does the HPCW attach to your wall? My 14-50 is recessed inside the wall, would that make it easier or harder to install a HPCW in the future?

 

[brkaus]

I thought you needed 4awg for the HPWC?

Also how does the HPCW attach to your wall? My 14-50 is recessed inside the wall, would that make it easier or harder to install a HPCW in the future?

The device has a setting inside to specify breaker size and thus limit max current. It can be set down to 15a breaker.

Set dial to match breaker and wiring.

Regarding recessed 14-50, there are all sorts of ways to connect it to the WC. Can put a plate on it with conduit coming out for example.

 

[jgd108]

I thought you needed 4awg for the HPWC?

Also how does the HPCW attach to your wall? My 14-50 is recessed inside the wall, would that make it easier or harder to install a HPCW in the future?

6 AWG for my setup of 48 amps charging / 60 amps breaker. If coming from NEMA like me I had 8 AWG wire so had to swap them out otherwise I was able to do 40 amps charging on 50 amps breaker.

I've used the low profile bracket but I should probably have used the top one, just didn't know ahead.

I actually like my setup, the cord is just long enough to put in the car without having to unroll the cable.

24 feet of cable is quite heavy!

 

[Glamisduner]

6 AWG for my setup of 48 amps charging / 60 amps breaker. If coming from NEMA like me I had 8 AWG wire so had to swap them out otherwise I was able to do 40 amps charging on 50 amps breaker.

I've used the low profile bracket but I should probably have used the top one, just didn't know ahead.

I actually like my setup, the cord is just long enough to put in the car without having to unroll the cable.

24 feet of cable is quite heavy!

Interesting, I thought it was 6awg for 40 amp continuous and 4awg was needed to safely charge at 48 amp continuous.

https://www.tesla.com/sites/default/files/downloads/US/universalmobileconnector_nema_14-50.pdf

I might be wrong, I guess I screwed up having the electrician use 4awg for the 14-50 (hoping to upgrade in the future)

 

[eprosenx]

Interesting, I thought it was 6awg for 40 amp continuous and 4awg was needed to safely charge at 48 amp continuous.

https://www.tesla.com/sites/default/files/downloads/US/universalmobileconnector_nema_14-50.pdf

You are correct if you are limited to the 60c rating of the wire (which you are with romex / NM) cable. In this case he is using THHN in conduit and so he can use the 75c rating.

 

[Glamisduner]

You are correct if you are limited to the 60c rating of the wire (which you are with romex / NM) cable. In this case he is using THHN in conduit and so he can use the 75c rating.

Ahh I had my electrician use THHN in conduit 4awg to the 14-50. Oh well it was only a few hundred dollars more.

Just need to get a two teslas to justify it I suppose.

 

[eprosenx]

Ahh I had my electrician use THHN in conduit 4awg to the 14-50. Oh well it was only a few hundred dollars more.

Just need to get a two teslas to justify it I suppose.

Look at the bright side: You could swap that 14-50 out for a Wall Connector and put in an 80a breaker which would let you charge at 64a (assuming you had a car that could make use of that like a Model S or X with the right charger could).

But yeah, you could have gotten away with two wire sizes smaller (8 awg) for just a 14-50 when run in conduit. (Tesla says 6 awg, but I think that is just to make the instructions as simple as possible - NEC clearly allows it)