My EVSE never leaves the garage. I usually leave it plugged into the outlet except for when I use my welder.
I have an EVSE from my 2015 Leaf that I use on the road. It's not as powerful (fewer amps), but it gets the job done.
Fire risk of common NEMA 14-50 outlets
- Thread starter Will Prowse
- Start date
My EVSE never leaves the garage. I usually leave it plugged into the outlet except for when I use my welder.
I have an EVSE from my 2015 Leaf that I use on the road. It's not as powerful (fewer amps), but it gets the job done.
CMDRZOD
New Member
One thing not mentioned here but I think deserves mentioning, especially here in Canada, is ambient temperature.
If you're in Utah charging your Tesla outdoors in 40C weather with the cables run through an unconditioned space, I would size up to #4 @ 48A.
Here at my location in northern Alberta, our ambient gets to about 35C max, and only for small stretches. I would run #6 for 48A. (Short run). For most of the year the cable will be very cool and only under a few circumstances would it be exposed to above 35C.
If you're in Utah charging your Tesla outdoors in 40C weather with the cables run through an unconditioned space, I would size up to #4 @ 48A.
Here at my location in northern Alberta, our ambient gets to about 35C max, and only for small stretches. I would run #6 for 48A. (Short run). For most of the year the cable will be very cool and only under a few circumstances would it be exposed to above 35C.
BarracudaBob
Harvesting free photons from clean fusion
This is good information I've always used the Hubble expensive ones from electrical parts provider.
Never knew about the EV stamp certification.
Does anyone have the actual part number that buy for the optimal one for charging EVs running generators through all the above?
Never knew about the EV stamp certification.
Does anyone have the actual part number that buy for the optimal one for charging EVs running generators through all the above?
zanydroid
Solar Wizard
I am pretty sure r/evcharging got a few reports of 14-50 failures on EVSE that were never unplugged
zanydroid
Solar Wizard
I don’t know if it’s a formal certification. One conspiracy meme I’ve heard is that Leviton realized that they could monetize the failures of their basic 14-50, by introducing a more expensive one, giving it the green EV stamp, and then putting footnotes in their basic shitty one saying it’s not recommended for EVs
Take that with a grain of salt.
zanydroid
Solar Wizard
VERY GOOD QUESTION.
An optimist might say, imagine how bad a non-listed receptacle would be.
bhbaker220
New Member
Worth noting that Grok 3 appears to me to be pretty accurate at calculating the temperature increase in the wire over a specified distance when I compared it to some YouTube videos that captured the heat profiles at various current loading. Much different results in temperature rise if you have your NEMA 14-50 next to your breaker panel than 30'-50' away. Can also tell you how long to reach a steady state temperature.
Can't argue with a good receptacle, tight terminal connections, and 90 degrees C THHN wire.
Can't argue with a good receptacle, tight terminal connections, and 90 degrees C THHN wire.
skyking1
Solar Enthusiast
I think the thing that most people don't consider about these sockets that are straight plug friction bites, they are frangible devices they wear out.
Add just a little bit of corrosion, things start to warm up. The spring tension gets softened up by the same action. I fight this all the time with 30 amp RV plugs. If you pull air conditioner loads on a 30 amp RV plug all the time all summer they tend to break down if there's any chance of just moisture in the air.
Add just a little bit of corrosion, things start to warm up. The spring tension gets softened up by the same action. I fight this all the time with 30 amp RV plugs. If you pull air conditioner loads on a 30 amp RV plug all the time all summer they tend to break down if there's any chance of just moisture in the air.
That doesn't surprise me. The Leviton outlet is just not up to the task.
zanydroid
Solar Wizard
I've even heard (a small) number of problems with running it well below capacity. Breaking at 32A is probably pretty common.
24A... I think I saw one in the past two weeks.
8 hours of EV charging at 24A, 32A, 40A are well above what those 14-50s are primarily used for (stoves, which are at best going to be like 15A during thanksgiving)
Another issue is the contact area between the wire and the connector/termination. The wire crushes flat a little, but the current is still flowing through a smaller area in the vicinity of the transition than it is in the run. So there's a more resistive spot at the connection, which heats up. Heavier wire also means more contact area at the transition.
.(Edit: Removed incorrect bogosity about extra heating from square law - that's square of current, but only directly proportional to resistance, though it does climb a little faster than linear because the resistance increases a bit with heat. Sorry, posted while sleepless running a fever. B-b )
Also, the flattening is dependent on the torquing of the connector, so use the torque wrench to make sure it got tight enough to crush the wire enough to meet design specs.
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zanydroid
Solar Wizard
I install a LOT of ev outlets and chargers.
It ALL depends on what vehicle the charger is for.
A lot of the chargers i install are for volvo vehicles. They pull a max 16A at 240V for those i install #6awg, using a leviton 14-50 base outlet on a 20A gfci breaker.
(The wiring will support up to a 40A charging system that way, all they have to do is get a larger breaker installed.)
Often, volvo sells tham a level 2 wall charger with their cars, so i hardwire them to a 50A circuit, since the chargers are gfci protected internally.
Knowing all the car will ever pull is 16A... no idea how volvo sells these chargers, but it will be fine to charge the next ev they buy...
Keep in mind, ANY outlets installed outside or in a garage need to be GFCI protected.
Outlets does not mean WALL RECEPTACLE... it means any electrically wired device.
Hard wired chargers need gfci protection.
Only hvac equipment is exempt from gfci protection, unless manufacturers request it.
Some states allow food storage equipment to be exempt, but not all...
It ALL depends on what vehicle the charger is for.
A lot of the chargers i install are for volvo vehicles. They pull a max 16A at 240V for those i install #6awg, using a leviton 14-50 base outlet on a 20A gfci breaker.
(The wiring will support up to a 40A charging system that way, all they have to do is get a larger breaker installed.)
Often, volvo sells tham a level 2 wall charger with their cars, so i hardwire them to a 50A circuit, since the chargers are gfci protected internally.
Knowing all the car will ever pull is 16A... no idea how volvo sells these chargers, but it will be fine to charge the next ev they buy...
Keep in mind, ANY outlets installed outside or in a garage need to be GFCI protected.
Outlets does not mean WALL RECEPTACLE... it means any electrically wired device.
Hard wired chargers need gfci protection.
Only hvac equipment is exempt from gfci protection, unless manufacturers request it.
Some states allow food storage equipment to be exempt, but not all...
Tesla recommends 75C rated breaker if you're running #6 to their wall connector and pulling continuous 48A:
Good advice
Good advice
Yup, and they recommend an 80A circuit and protection.
I have one new in box if anybody needs one.
Only has an 8' cord though...
Only has an 8' cord though...
Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
- Messages
- 23,157
I did read articles about quality of NEMA 14-50 outlets a while back.
Apparently the garden variety I've always picked up might not be great for continuous duty.
I use 4-prong 30A or 50A to test inverters and do other temporary stuff. Like power my circuit breaker tester (step-down transformer with resistive loads.)
Here are some comments on Reddit with a picture of a melted outlet
I was going to do this for my lab (one outlet feeding a breaker panel with many circuit), then discovered a 60A welder cord and ceramic 60A outlet so used that instead.
It seems higher quality outlets will stay cooler and not melt.
For normal ambient temperatures, 6 awg ought to be fine for 50A continuous, considering 75 degree C rating of connectors.
But some of these sockets do have rinky-dink screw terminals.
Apparently the garden variety I've always picked up might not be great for continuous duty.
I use 4-prong 30A or 50A to test inverters and do other temporary stuff. Like power my circuit breaker tester (step-down transformer with resistive loads.)
Here are some comments on Reddit with a picture of a melted outlet
I was going to do this for my lab (one outlet feeding a breaker panel with many circuit), then discovered a 60A welder cord and ceramic 60A outlet so used that instead.
It seems higher quality outlets will stay cooler and not melt.
For normal ambient temperatures, 6 awg ought to be fine for 50A continuous, considering 75 degree C rating of connectors.
But some of these sockets do have rinky-dink screw terminals.
@Supervstech what outdoor rated box do you recommend that can hold a Hubble or Bryant 14-50 receptacle? The Lowe’s/HD outdoor rated boxes don’t seem to fit these industrial outlets. Will be running at 40amp.
k490
Solar Enthusiast
I have had my hot tub wired up with 6 gauge its never gotten warm. It pulls 50 amps and 240V when the heater turns on about 70 feet from the panel. There is no plug involved the spa has lugs where the wire connects it even says only use 6 Gauge wire on the lugs. Would the plug for the EV cause some resistance make the wires to get warm seems like just the plug would get warm.
I have the mobile connector and used it for a month or so, using the standard cheap Leviton , but made sure to limit the charge rate down, have never used it after installing the wall connector.
The wall connector works out well since it is only 4 feet from the panel and terminates directly on the breaker and has the temperature measuring/sensing inside the wall connector and also inside the NACS . I should order up the more industrial Bryant 6 50 R and throw the leviton in the garbage can.
The EV charger definitely will pull non stop until % charge is reached if programmed to do so, so more of a continuous duty at rated/selected amps situation every time.
The wall connector works out well since it is only 4 feet from the panel and terminates directly on the breaker and has the temperature measuring/sensing inside the wall connector and also inside the NACS . I should order up the more industrial Bryant 6 50 R and throw the leviton in the garbage can.
Same, but a hot tub will not keep the heater element on non stop usually, so you end up with a somewhat regular pulsing load effect, I guess it would on initial fills
The EV charger definitely will pull non stop until % charge is reached if programmed to do so, so more of a continuous duty at rated/selected amps situation every time.
What is the temperature rating of the breaker you're using
k490
Solar Enthusiast
I will have to check it's a GFCI breaker about 10 feet away then 70 feet back to my main another breaker there. I'm betting it's 60C/75C rated. Tried to pull up some specs online not easy to find so many different breakers made. Breakers are all 50 amps breakers.
Although I did a quick internet search and found that NEC 625.41 says continuous loads require 125% over current protection device. Which means really should be wiring it with 4 gauge. https://forums.mikeholt.com/threads/tesla-charger.2584904/#post-2966752
If I just filled it with cold water runs the heater for hours until it's hot.
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dougbert
Solar Wizard
very good question as I have NOT found an outdoor box with the larger size hole
small sized hole box here
I got one of those and reamed the hole to the larger size
the Bryant/Hubbel units are larger hole size (2.48/63mm) than the cheapo units (2.15 inch diameter center hole)
larger face plate
Wires shouldn't feel warm to the touch as that is just excessive losses. The regulations are just the bare minimum and assume best case scenarios. You guys would do better with going one size up, even with copper because you have the same high power requirements yet lower voltages than in other parts of the world. Same for the outlets, they are flimsy and could do with a redesign.
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