Master Thread: Definitive 14-50 NEMA Outlet Guide

[Gauss Guzzler]

Here is my sub-panel status: 125A max panel size, main cut off breaker for sub panel is 90A.

1. Do I have option for 30A addition ?

• The breakers will need to shuffle to add room for dual-30A : move the bottom 20A to the right with corresponding wiring ?
• The main wires, #1/0 wiring size, correct ?

There are some rules, like don't feed a 125A rated panel with breaker larger than 125A, and don't load this 90A supplied subpanel with more than 72A for more than 3 hours. But otherwise "capacity" is generally subjective and note that high-power devices like the oven, dryer, air conditioner, etc. likely only use around half of their breaker-rating.

I'd replace those 4 15A breakers at the bottom right with a pair of tandem breakers and then add a 60A breaker for your wall charger if conduit is preferred, or 50A if Romex is preferred. Then if you find that charging at 48A (conduit) or 40A (Romex) causes trouble when using the oven or whatever, either change your habits or dial it down to the next level in the charger.

Of course this all gets a lot more complicated, expensive, and unreliable if you're thinking about using an outlet instead of a direct-wired wall charger, and maybe you are, considering the topic of this thread. If so, you'd want a 50A GFCI breaker and you lose the ability to limit the charge rate right at the charger, but still have the ability to configure the car for location-based charge rate limiting.

And yes, 1/0 wiring is fine for 90A service, even the next smaller size works in most cases.

 

[3sr+buyer]

A photo that seems to be around the web. From

https://www.reddit.com/r/electricvehicles/comments/ygjovb

 

[EV4m32]

There are some rules, like don't feed a 125A rated panel with breaker larger than 125A, and don't load this 90A supplied subpanel with more than 72A for more than 3 hours. But otherwise "capacity" is generally subjective and note that high-power devices like the oven, dryer, air conditioner, etc. likely only use around half of their breaker-rating.

I'd replace those 4 15A breakers at the bottom right with a pair of tandem breakers and then add a 60A breaker for your wall charger if conduit is preferred, or 50A if Romex is preferred. Then if you find that charging at 48A (conduit) or 40A (Romex) causes trouble when using the oven or whatever, either change your habits or dial it down to the next level in the charger.

Of course this all gets a lot more complicated, expensive, and unreliable if you're thinking about using an outlet instead of a direct-wired wall charger, and maybe you are, considering the topic of this thread. If so, you'd want a 50A GFCI breaker and you lose the ability to limit the charge rate right at the charger, but still have the ability to configure the car for location-based charge rate limiting.

And yes, 1/0 wiring is fine for 90A service, even the next smaller size works in most cases.

Thank you: I perhaps do not need to shuffle since there is 10/12 slot on each side being use ? then add a 50A tandem ?

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I do aware of the 80% and GCFI rule so no, hard wired : since my EV-farm ( Leaf, PriusPrime and M3) are 16A-32A charging rate, they will be self limit ...

I do think about NEMA pro-con and up to this point, they do not serve my need .
For now, they will be in-wall so Romex it is when I ready to dive in and pull the permit .

TIA,

 

[hiker007]

I found the following outlets from my local suppliers vary from $20-60.
1) Square D™ SQR46501BK, ~$21 It's well known brand. It says commercial grade but I doubt.

https://download.schneider-electric.com/files?p_enDocType=Instruction+sheet&p_File_Name=GDE77949.pdf&p_Doc_Ref=GDE77949

2) Eaton Cooper 1258-SP (good review on Amazon)

https://www.eaton.com/us/en-us/skuPage.1258-SP.html

3) Legrand-Pass & Seymour 3894, use Thermoplastic

ST BLD RECP 50A 125/250 3P 4W NAFTA | Power Outlets | Outlets and Receptacles | Wiring Devices

Straight Blade Receptacle 50A 125/250 3P 4W NAFTA

www.legrand.us

Anyone used any of these? or are they just at the same level as Leviton?

 

[3sr+buyer]

I found the following outlets from my local suppliers vary from $20-60.
1) Square D™ SQR46501BK, ~$21 It's well known brand. It says commercial grade but I doubt.

https://download.schneider-electric.com/files?p_enDocType=Instruction+sheet&p_File_Name=GDE77949.pdf&p_Doc_Ref=GDE77949

2) Eaton Cooper 1258-SP (good review on Amazon)

https://www.eaton.com/us/en-us/skuPage.1258-SP.html

3) Legrand-Pass & Seymour 3894, use Thermoplastic

ST BLD RECP 50A 125/250 3P 4W NAFTA | Power Outlets | Outlets and Receptacles | Wiring Devices

Straight Blade Receptacle 50A 125/250 3P 4W NAFTA

www.legrand.us

Anyone used any of these? or are they just at the same level as Leviton?

Take a look into the plug holes to see if the plug blade contacts are full size brass.

 

[stopcrazypp]

I found the following outlets from my local suppliers vary from $20-60.
1) Square D™ SQR46501BK, ~$21 It's well known brand. It says commercial grade but I doubt.

https://download.schneider-electric.com/files?p_enDocType=Instruction+sheet&p_File_Name=GDE77949.pdf&p_Doc_Ref=GDE77949

2) Eaton Cooper 1258-SP (good review on Amazon)

https://www.eaton.com/us/en-us/skuPage.1258-SP.html

3) Legrand-Pass & Seymour 3894, use Thermoplastic

ST BLD RECP 50A 125/250 3P 4W NAFTA | Power Outlets | Outlets and Receptacles | Wiring Devices

Straight Blade Receptacle 50A 125/250 3P 4W NAFTA

www.legrand.us

Anyone used any of these? or are they just at the same level as Leviton?

Use the search (put the keyword, then you can narrow to this thread), others already reviewed the 3894 fairly early on:
Master Thread: Definitive 14-50 NEMA Outlet Guide

Commercial grade is actually meaningless, many commercial grade products are actually made cheaply too. Tesla actually calls for "industrial grade", the models given as examples are in the first post of this thread:
Hubbell part # HBL9450A, Cooper part #5754N
https://www.tesla.com/sites/default/files/downloads/en_CA/CA-EN NEMA 14-50 Installation Guide.pdf

Cooper was bought by Eaton:
https://www.eaton.com/us/en-us/skuPage.5754N.html

The Bryant 9450FR is a sub brand of Hubbell and almost identical to the Hubbell 9450A. Grainger is a common place to buy it given they sell it under $50:
https://www.grainger.com/product/49YY93?RIID=67664103235

As per the first post of this thread, what separates these three "industrial" models from most other cheaper models is the diameter of the front is larger at 2.465" vs the standard 2.15" diameter and thus requires a different faceplate. I detail compatible large diameter face plates here:
https://teslamotorsclub.com/tmc/posts/6266356/

As another mentioned, if you want to go on a budget and not get an industrial one, the main issue with the Leviton is the contacts are not full size. If you look into the contacts for the models you are interested in, make sure they are full size. It would already be an upgrade over the Leviton if that is the case.

 

[zroger73]

Very helpful summary.

I've never understood why someone wants to spend $15 instead of a $45 on a receptacle when their $50,000 to $150,000 automobile, home, and lives are at risk.

 

[EV4m32]

Pls do a search and you will find -no one- would recommend Lev* and only ask for Hubbell or Bryant.

and the burning start within a year of usage, with no disconnect/re connect at all ( my neighbor ).

No chance I would use it.

 

[zroger73]

And more specifically, make sure it's the right model of Hubbell or Bryant (since they make both an "industrial" version and a "Leviton" version).

 

[3sr+buyer]

As per the first post of this thread, what separates these three "industrial" models from most other cheaper models is the diameter of the front is larger at 2.465" vs the standard 2.15" diameter and thus requires a different faceplate. I detail compatible large diameter face plates here:
Master Thread: Definitive 14-50 NEMA Outlet Guide

As another mentioned, if you want to go on a budget and not get an industrial one, the main issue with the Leviton is the contacts are not full size. If you look into the contacts for the models you are interested in, make sure they are full size. It would already be an upgrade over the Leviton if that is the case.

For 14-50 and 6-50 outlets, the larger size of most non-Leviton outlets does mean that you need a bigger box. If replacing a Leviton outlet with something else, you may need to replace the box or add a box extender.

The size and material of the contacts is the main issue with overheating at the plug, which seems to be where most of the reported melting incidents occur with Leviton outlets. It can also cause the Tesla plug to detect excessive heat and reduce charging amperage (prevents melting, but limits charging speed). Leviton outlets have half size steel contacts versus larger brass contacts in most other outlets.

The wire clamping mechanism on the Hubbell and Bryant 14-50 (but not 6-50) outlets does make it easier to install correctly and harder to install poorly than the screw-down wire clamping in most other outlets. However, careful installation with screw-down wire clamping will work safely, although poor installation could result in overheating on the back side of the outlet.

 

[n2mb_racing]

I have a cooper 5754N 14-50 outlet that was installed in 2017. It has mostly worked, but occasionally the UMC throttles current down from 32A to 16A. I've stripped the wires and re-tightened the connections several times. I just did it again today, but it still throttles after about 1-2 hours of continuous charging at 32A. I tightened the screws absolutely as hard as I could using a regular screwdriver. Any other ideas? Replace the outlet? Or try using an impact driver?

The other change I can think of is that I've recently insulated the garage, and it is 72 degrees here, so problem seems to increase with warmer weather and the insulation probably doesn't help.

 

[jwharnish]

I have a cooper 5754N 14-50 outlet that was installed in 2017. It has mostly worked, but occasionally the UMC throttles current down from 32A to 16A. I've stripped the wires and re-tightened the connections several times. I just did it again today, but it still throttles after about 1-2 hours of continuous charging at 32A. I tightened the screws absolutely as hard as I could using a regular screwdriver. Any other ideas? Replace the outlet? Or try using an impact driver?

The other change I can think of is that I've recently insulated the garage, and it is 72 degrees here, so problem seems to increase with warmer weather and the insulation probably doesn't help.

Replace the outlet. Charging rates throttles down once charging senses overheat situation. 16a seems to be default number. Make sure adapter plug is fully inserted into brick charger. It problem increases with temp, another indication overheating at plug.

 

[davewill]

I have a cooper 5754N 14-50 outlet that was installed in 2017. It has mostly worked, but occasionally the UMC throttles current down from 32A to 16A. I've stripped the wires and re-tightened the connections several times. I just did it again today, but it still throttles after about 1-2 hours of continuous charging at 32A. I tightened the screws absolutely as hard as I could using a regular screwdriver. Any other ideas? Replace the outlet? Or try using an impact driver?

The other change I can think of is that I've recently insulated the garage, and it is 72 degrees here, so problem seems to increase with warmer weather and the insulation probably doesn't help.

This sounds more like the on-board charger going out, than the UMC overheating. You may be able to go into service mode and find an error message to help you determine which it is. Also, when it throttles, check the screen in the car. If it is the UMC, you should see "16/16a", but if it's the car you will see "16/32a". You can also check the temperature of the outlet after charging at 32a for a while. Unplug the car and the UMC from the wall and carefully feel the blades on the 14-50 plug. They should be warm, but not too hot to keep your fingers on.

 

[n2mb_racing]

This sounds more like the on-board charger going out, than the UMC overheating. You may be able to go into service mode and find an error message to help you determine which it is. Also, when it throttles, check the screen in the car. If it is the UMC, you should see "16/16a", but if it's the car you will see "16/32a". You can also check the temperature of the outlet after charging at 32a for a while. Unplug the car and the UMC from the wall and carefully feel the blades on the 14-50 plug. They should be warm, but not too hot to keep your fingers on.

Hmm. Yeah. I did get the error below. The blades weren't hot, but it was charging at 16A for the last few hours. I just tried swapping to another UMC that I have, but I only have one 14-50 UMC plug, so that part will be the same, if it is the issue.

 

[davewill]

Hmm. Yeah. I did get the error below. The blades weren't hot, but it was charging at 16A for the last few hours. I just tried swapping to another UMC that I have, but I only have one 14-50 UMC plug, so that part will be the same, if it is the issue.

View attachment 924890

Yeah, the time to check the temperature is before it throttles down. However, that error shows that it's definitely the wall plug. I go along with replacing the outlet with something better, and verifying that all the wiring is the correct gauge. For a 50a breaker, that would be 6 gauge, and for a 40a breaker, that would be 8 gauge. Either is sufficient for modern mobile connectors. Other things to check for is that the proper amount of insulation is stripped back, there isn't any insulation trapped under the screw terminals, and that the wire isn't damaged (broken or nicked strands).

 

[n2mb_racing]

Yeah, the time to check the temperature is before it throttles down. However, that error shows that it's definitely the wall plug. I go along with replacing the outlet with something better, and verifying that all the wiring is the correct gauge. For a 50a breaker, that would be 6 gauge, and for a 40a breaker, that would be 8 gauge. Either is sufficient for modern mobile connectors. Other things to check for is that the proper amount of insulation is stripped back, there isn't any insulation trapped under the screw terminals, and that the wire isn't damaged (broken or nicked strands).

Yup. It's 6 awg on a 50A breaker. Well stripped and not damaged. I removed the wires this morning and put them back in.

Yeah, I think I'll try a new outlet. Thanks!

 

[zroger73]

Another possibility is a high-resistance path inside the mobile connector's plug.

 

[n2mb_racing]

Is the best outlet / deal still currently this one?

https://www.grainger.com/product/49YY93

 

[pimfram]

For what it's worth, my el cheapo outlet dying mirrored exactly what you're experiencing. Confirm with another L2 charger if you can before you just assume it's the outlet, however.

 

[zroger73]

Is the best outlet / deal still currently this one?

https://www.grainger.com/product/49YY93

Yes - and I see the price finally increased. It was $45.88 for the last couple of years.