Master Thread: Definitive 14-50 NEMA Outlet Guide

[stopcrazypp]

Outside temp is in the mid 80s with it being in the mid 90s in my garage so I thought I’d test charging our M3LR at the max 40a I can do. I started monitoring the temp of the outlet, plug, and cord going into the Grizzl-E charger and after about 30 minutes the highest temp I saw was on the side of the plug at 182 degrees F. The outlet was around 150 and cord was around 135. Nonetheless I dropped the amperage to 24 as I was not comfortable with those temps. The outlet is a Legrange rated at 75C. I really hate not being able to take advantage of the full 40a my charger can do. I submitted a ticket to Grizzl-E two days ago and have yet to hear anything.

The higher rated wires are only rated for 90C (194F), some rated for 75C (167F), so that seems a bit high.

I see in other threads for people with hot outlets in hot weather with the HPWC, for some people a breaker and outlet swap fixed things. Although for some it required a HPWC replacement (the ones still with 14-50 pigtails).
14-50 Wall connector over heating

Although hot weather does raise the temps proportionately (especially if there is poor to no ventilation on a hot day), a hot plug does usually point to a loose connection somewhere.

I don't really have a thermometer to test nor have I tried feeling the plug if it is hot, but I have charged when it is in the 80s outside (probably closer to 90s in garage where my 14-50 outlet is at) and my mobile connector at 32A does not have problems or throttling (knock on wood). My outlet however is right under my subpanel, and my main panel and service entrance is right on the opposite wall and a few feet away, so I have a relatively low resistance connection.

 

[Jason Bourne]

Update: my order has shipped and I received UPS tracking number. So it seems they actually do have them in stock.

Update: receptacle delivered.

 

[ElectricNerd]

The higher rated wires are only rated for 90C (194F), some rated for 75C (167F), so that seems a bit high.

I see in other threads for people with hot outlets in hot weather with the HPWC, for some people a breaker and outlet swap fixed things. Although for some it required a HPWC replacement (the ones still with 14-50 pigtails).
14-50 Wall connector over heating

Although hot weather does raise the temps proportionately (especially if there is poor to no ventilation on a hot day), a hot plug does usually point to a loose connection somewhere.

I don't really have a thermometer to test nor have I tried feeling the plug if it is hot, but I have charged when it is in the 80s outside (probably closer to 90s in garage where my 14-50 outlet is at) and my mobile connector at 32A does not have problems or throttling (knock on wood). My outlet however is right under my subpanel, and my main panel and service entrance is right on the opposite wall and a few feet away, so I have a relatively low resistance connection.

My outlet is about 4 feet to the right of my panel. I really do think I had a bad electrician.

 

[boingolover]

But does the Bryant outlet work well with tinned copper, or am I stuck using a residential grade outlet?

For what it's worth, the Eaton / Cooper 5754N is good for aluminum or copper wire and is an industrial rated outlet. It's also significantly cheaper than hubbell / bryant outlets, and easier to find. Eaton owns Cooper, and they don't seem to brand the 5754N as a Cooper anymore, but the Eaton 5754N the same thing as the Cooper 5754N mentioned on the first post of this thread.

 

[3sr+buyer]

A Youtuber noticed that the Leviton 14-50 outlet's plug prong contacts are significantly smaller than the prongs:

Perhaps this may result in greater heating due to the smaller contact area between the contacts and the prongs.

I noticed a similar characteristic with a Leviton 6-50 outlet:

NEMA 6-50 outlets: Leviton versus Bryant

So I had a pre-existing 40A circuit with a Leviton 6-50 outlet with a 30A EVSE plugged into it for a previous EV. It worked fine with no problems then. That EVSE was not very reliable for the Model 3, so I put the (then included) mobile connector with 6-50 plug adapter in it. Worked fine for...

teslamotorsclub.com

 

[Rocky_H]

A Youtuber noticed that the Leviton 14-50 outlet's plug prong contacts are significantly smaller than the prongs:

Yep, on page 3 of this thread, someone found that and posted some very close comparison pictures of it, and it's pretty bad.

Master Thread: Definitive 14-50 NEMA Outlet Guide

I think the last question... is there a difference between 14-50R and 14-50? I think from that amazon picture the Hubbell says 14-50R on it... that will fit the 14-50 cord Tesla sells, right? the 14-50 is the plug, 14-50R is the receptacle or outlet, all the 14-50 outlets will be marked with an...

teslamotorsclub.com

 

[3sr+buyer]

The plug blade contact issue was not really addressed in the first post of this thread that most people will see (many will not get to post #60 which shows the plug blade contact issue), even though the plug blade contact issue may be quite common, and not as easily mitigated by careful installation. The first post also seems to make cosmetic arguments against the Leviton outlet that really are not that relevant.

Really, there are multiple issues in outlet selection:

• Wire connection methods. Most outlets appear to use screw-down connections (where the screw itself presses the wire against a brass contact surface). The Hubbell and Bryant 9450FR for NEMA 14-50R uses connections that clamp the wire more securely with less room for installation mistakes (but note that the Bryant 9650FR for NEMA 6-50R uses screw-down connections). However, careful installation of an outlet with screw-down connections can avoid problems here. Proper installation is very important, since any heat buildup at the wire connections may be less detectable by the heat sensor in the plug head of a Tesla mobile connector.
• Plug blade contacts. Most outlets appear to use brass contacts that contact the full plug blades. The Leviton outlets for NEMA 14-50R and 6-50R use steel contacts that contact only about half of the plug blades. Since steel is less conductive than brass, and the contact area is only half of the blade, the electrical resistance and heat generation is greater, leading to issues of excess heat at the plug. The Leviton outlets appear to be marginal for 32A charging, since the Tesla mobile connector seems prone to reducing current due to heat detection, particularly in warmer weather (the heat can be felt at the plug head). In more extreme cases, melting at the plug and outlet interface has occurred (even when there wire connections are not melted, indicating good installation). The smaller plug blade contacts may also be more prone to bending out of position (further reducing contact area and increasing resistance and heat) if (as not recommended) the plug is inserted and removed frequently.
• Physical size. Some outlets are larger than others. The Leviton outlets appear to be among the smaller ones, so if replacing a Leviton outlet with a different one, it may be necessary to replace the outlet box with a larger one, or add a box extension.

 

[ElectricNerd]

Finally tested the temp issue with using the Tesla mobile charger to see how hot it would get. The hottest it got was 120 degrees whereas the 3rd party charger would reach 155-160 degrees at the plug. The Tesla power cord is about half the diameter of the 3rd party charger. Definitely not the outlet. Interesting though is part way through charging my SR+ it dropped to 16a max. Disconnecting and reconnecting the charger let me go back to 32a. Sure hope I don’t have an issue.

I have a Tesla Wall Connector on order and am deciding between using the 14-50 or hardwiring it to the breaker box. I’d have to swap the breaker with a 60a and I’m assuming I can’t use the existing wiring from the 14-50. Also debating if I want to do that myself. I’ve had bad luck with electricians and can’t get a good one to come by.

 

[3sr+buyer]

I have a Tesla Wall Connector on order and am deciding between using the 14-50 or hardwiring it to the breaker box. I’d have to swap the breaker with a 60a and I’m assuming I can’t use the existing wiring from the 14-50. Also debating if I want to do that myself. I’ve had bad luck with electricians and can’t get a good one to come by.

If you hardwire it into the existing circuit that currently has a 14-50 outlet on it, then you need to set it to give a maximum of 32A or 40A (depending on if your circuit and breaker are 40A or 50A). If you want it to charge up to 48A, then you need to hardwire it to a 60A circuit.

 

[ElectricNerd]

If you hardwire it into the existing circuit that currently has a 14-50 outlet on it, then you need to set it to give a maximum of 32A or 40A (depending on if your circuit and breaker are 40A or 50A). If you want it to charge up to 48A, then you need to hardwire it to a 60A circuit.

Will I need to replace the wiring to run it at 60a? It’s 6/3 I believe.

 

[wws]

Will I need to replace the wiring to run it at 60a? It’s 6/3 I believe.

Is it Romex? Or THHN in conduit?

 

[ElectricNerd]

Romex. I got two quotes from two electric companies. Both told me I’d need 4/3 in order to utilize a 60a breaker. Both quotes are over $750 just for the electrical work. I might as well just keep the 14-50 outlet and run it at the 40a max charge amperage. I can’t see paying that just to get another 8a capability.

Any issues running the TWC with a 14-50 plug? Will Tesla balk at any warranty issues doing that?

 

[Genie]

Romex. I got two quotes from two electric companies. Both told me I’d need 4/3 in order to utilize a 60a breaker. Both quotes are over $750 just for the electrical work. I might as well just keep the 14-50 outlet and run it at the 40a max charge amperage. I can’t see paying that just to get another 8a capability.

Any issues running the TWC with a 14-50 plug? Will Tesla balk at any warranty issues doing that?

Consider removing the 14-50 and using that box as a junction box, run 6awg THHN or equiv in conduit to WC location and charge at 40A. The 14-50 is an unneccessary weak link in the chain for your WC.

 

[ElectricNerd]

Consider removing the 14-50 and using that box as a junction box, run 6awg THHN or equiv in conduit to WC location and charge at 40A. The 14-50 is an unneccessary weak link in the chain for your WC.

What would I use to tie the THHN into the junction box?

 

[Genie]

What would I use to tie the THHN into the junction box?

Split bolts or wire nuts

 

[Rocky_H]

I have a Tesla Wall Connector on order and am deciding between using the 14-50 or hardwiring it to the breaker box. I’d have to swap the breaker with a 60a and I’m assuming I can’t use the existing wiring from the 14-50.

From this and your next few comments, it sounds to me like there is something really big you are misunderstanding, and I didn't see anyone else notice it to correct it yet.

You are talking about this like you think the wall connector device is built to be 60A ONLY. It's not. It is a configurable device. You can put that on a 15 or 20 or 30 amp circuit if you wanted to. It doesn't have to be a 60A circuit. The way you talked about having to rip out the wires from the 14-50 to use the wall connector made me realize you didn't realize the wall connector can be installed on those very same wires and set as a 50A circuit. So just do that. The other advantage to this is that code requires that if you're doing an outlet, it must use a GFCI breaker type, and those are stupid expensive (like $130) and kind of hard to find sometimes. If you are doing a hard wired device, it can use the cheaper normal kind of breaker. So I would just get the 50A breaker and hard wire it.

 

[ElectricNerd]

From this and your next few comments, it sounds to me like there is something really big you are misunderstanding, and I didn't see anyone else notice it to correct it yet.

You are talking about this like you think the wall connector device is built to be 60A ONLY. It's not. It is a configurable device. You can put that on a 15 or 20 or 30 amp circuit if you wanted to. It doesn't have to be a 60A circuit. The way you talked about having to rip out the wires from the 14-50 to use the wall connector made me realize you didn't realize the wall connector can be installed on those very same wires and set as a 50A circuit. So just do that. The other advantage to this is that code requires that if you're doing an outlet, it must use a GFCI breaker type, and those are stupid expensive (like $130) and kind of hard to find sometimes. If you are doing a hard wired device, it can use the cheaper normal kind of breaker. So I would just get the 50A breaker and hard wire it.

Got it. The current 50a breaker is not a GFCI as the 3rd party charger using the outlet now has its own GFCI. I thought the TWC had its own built in GFCI and wasn’t supposed to use a GFCI breaker?

 

[Rocky_H]

Got it. The current 50a breaker is not a GFCI as the 3rd party charger using the outlet now has its own GFCI. I thought the TWC had its own built in GFCI and wasn’t supposed to use a GFCI breaker?

They are two separate things. Yes, a requirement of every piece of EVSE equipment is that they all must have GFCI built into them.

But additionally, it is now a requirement of the National Electric Code, starting in the 2017 version, that ANY outlet being installed for the purpose of charging an electric car MUST use a GFCI breaker. So it is both.

Here's why they somewhat make sense. The GFCI in the equipment protects everything downstream of that--toward the plug end that you would be holding if you are plugging or unplugging it from the car. But the end upstream from that, where you are pushing the plug into the outlet in the wall can't be protected by that electronics farther down. If your finger slips and touches a prong while you are plugging it in, the circuit in the wall has to detect that somehow and interrupt. So that's what the GFCI breaker is for. So the reason hardwired devices don't require that is that they are installed and screwed in before you turn on the breaker and then all of the wire connections are hidden inside--people aren't touching them with their hands, so no need for that.

 

[ElectricNerd]

They are two separate things. Yes, a requirement of every piece of EVSE equipment is that they all must have GFCI built into them.

But additionally, it is now a requirement of the National Electric Code, starting in the 2017 version, that ANY outlet being installed for the purpose of charging an electric car MUST use a GFCI breaker. So it is both.

Here's why they somewhat make sense. The GFCI in the equipment protects everything downstream of that--toward the plug end that you would be holding if you are plugging or unplugging it from the car. But the end upstream from that, where you are pushing the plug into the outlet in the wall can't be protected by that electronics farther down. If your finger slips and touches a prong while you are plugging it in, the circuit in the wall has to detect that somehow and interrupt. So that's what the GFCI breaker is for. So the reason hardwired devices don't require that is that they are installed and screwed in before you turn on the breaker and then all of the wire connections are hidden inside--people aren't touching them with their hands, so no need for that.

Got it, that tells me the electrician I used 3 months ago to install the 14-50 outlet didn’t know what he was doing as he installed a non-GFCI 50a breaker, and he knew it was for an EV charger.

 

[Genie]

Got it, that tells me the electrician I used 3 months ago to install the 14-50 outlet didn’t know what he was doing as he installed a non-GFCI 50a breaker, and he knew it was for an EV charger.

But you are most of the way there for a hardwire install, if your WC is going right where the 14-50 is you’ll only need a couple feet of wire to reach the WC lugs from the romex in the box.