Wiring a 14-50 outlet: What size wire & using the Mobile Connector plugs

  • SUPPORT THE SITE AND ENJOY A PREMIUM EXPERIENCE!
    Welcome to Tesla Owners Online, four years young! For a low subscription fee, you will receive access to an ad-free version of TOO. We now offer yearly memberships! You can subscribe via this direct link:
    https://teslaownersonline.com/account/upgrades

    SUBSCRIBE TO OUR YOUTUBE CHANNEL!
    Did you know we have a YouTube channel that's all about Tesla? Lots of Tesla information, fun, vlogs, product reviews, and a weekly Tesla Owners Online Podcast as well!

kyrral

Active member
Joined
Sep 29, 2018
Messages
65
Location
Pomona, CA
Tesla Owner
Model 3
Country
Country
#1
I know I need a 6 or 8 guage to the 2 power terminals but what size wire would suffice for the ground and neutral?

On a separate note I have the 14-50 plug but I don't see how to attach that to the Tesla 110 plug.
 
1

13004

Guest
#2
Oh my........first of all, I have no certifications of any kind whatsoever and know < zero about residential wiring. Do not take advice from hacks (such as me!) on the internet!

Since your on a 3 thread, I am going to assume that you are deploying the supplied Gen II MC with a 32A max capacity and that your branch circuit is not too far from your load center, and that you are using NM Romex wiring. It is just plum silly that the Tesla electomagician youngster keeps supplying/pushing these NEMA 14-50 adapters which is a carryover from the days when we needed to charge at campgrounds on road trips before the supercharger network was built out. Deploying a 14-50 over a 6-50 is a waste of copper and $ since there is not an EV in North America that uses the neutral for 240V charging, in fact, the neutral prong is dead on the adapter and is not recognized by the car for 240V charging (rant over). Here is some info that I picked up from some sites on the internet over the years. I have no idea if the below info is correct or not. Personally, I would verify it before following.
Gen I UMC 14-50 40 amp max rated 6/3 Romex (min) 50A 2-pole breaker (U.S.)
Gen I UMC 14-50 32 amp max rated dunno.............................................(Canada)
Gen II MC 14-50 32 amp max rated 8/3 Romex (min) 40A 2-pole breaker (U.S.)

when I wired up Billy Bob's barn back home in West Virginia for his EV, I used the same size for the neutral and one wire size smaller for the ground than the L1 + L2 conductors.

don’t believe any of the above and hire a certified electrican since the consequences could be catastrophic!

btw, re-reading your post with its judicious misuse of very conflicting terminology has “me thinks” I got punked. :tearsofjoy:
 
Last edited by a moderator:

Madmolecule

Top-Contributor
Green Level Supporter
Joined
Oct 7, 2018
Messages
401
Location
Duluth, GA
Tesla Owner
Model 3
Country
Country
#3
1

13004

Guest
#4
Not sure why you deployed 6/3+ground instead of 6/2+ground for a WC. All HPWCs and WCs must be grounded.

Yup on the 50 setting maxing out at 40A.

Hopefully a FO REALZ electromagician will jump in this thread.
 
Last edited by a moderator:

Madmolecule

Top-Contributor
Green Level Supporter
Joined
Oct 7, 2018
Messages
401
Location
Duluth, GA
Tesla Owner
Model 3
Country
Country
#5
I went with the 6/3 because the neutral wire was a #6 and the bare ground cable was a #12. In the US the Neutral and ground are bonded, so I went with the heaver gauge wire. There was no place to connect the ground on the wall connector side. I considered terminating it to the same socket that the Neutral wire was connected but I decided not to.
 

garsh

Dis Member
Moderator
TOO Supporting Member
Joined
Apr 4, 2016
Messages
12,407
Location
Pittsburgh PA
Tesla Owner
Model 3
Country
Country
#7
I know I need a 6 or 8 guage to the 2 power terminals but what size wire would suffice for the ground and neutral?
If you're purchasing Romex, then all four conductors will be the same gauge.

But if you're installing in conduit, you need to pull separate conductors, so I guess that's what you're planning. I'm not sure if you're permitted to go with a lower gauge for ground or neutral. Even if you are, you probably shouldn't.
On a separate note I have the 14-50 plug but I don't see how to attach that to the Tesla 110 plug.
I assume you're talking about your Mobile Connector that came with the car? If so, you have to remove the 5-15 plug from the Mobile Connector in order to attach the 14-50 plug. Your car should have came with both of those adapters (The NEMA 5-15 adapter is your "110 plug"). You have to pull fairly hard to get it out. Here's what all of the various adapters look like when disconnected, so you know where to pull.

 
Last edited:

kyrral

Active member
Joined
Sep 29, 2018
Messages
65
Location
Pomona, CA
Tesla Owner
Model 3
Country
Country
#8
Garsh, All of those use the 5 pin connectors. I need something to attach to my 110 with 2 poles and a ground.
 

garsh

Dis Member
Moderator
TOO Supporting Member
Joined
Apr 4, 2016
Messages
12,407
Location
Pittsburgh PA
Tesla Owner
Model 3
Country
Country
#9
Garsh, All of those use the 5 pin connectors. I need something to attach to my 110 with 2 poles and a ground.
I think you are confused. BUT... it could just be me being confused. Can you take pictures of exactly *what* you're trying to plug in *where*?

In the picture that I posted, the left-most adapter is the one that plugs into a regular household 120v outlet.
The other end plugs into the Mobile Connector that was included with your Model 3. This adapter was probably already plugged into your Mobile Connector when you received it - you'll have to pull it out.
 

kyrral

Active member
Joined
Sep 29, 2018
Messages
65
Location
Pomona, CA
Tesla Owner
Model 3
Country
Country
#11
On another note I wrote to Tesla and got this reply: Would this work? I'll never need to use the plug for anything other than to charge the 3.

Using a 14-50 outlet what size wire should go to the hot plugs and what size to the ground and neutral? thanks. Larry

Can I use a 40 amp breaker for this or do I need to go to 50 (as the mobile wire only draws 32 amp). I'm not asking for me but to pass along info to an electrician. thanks ahead.




we recommend installing the NEMA 14-50 on a 50 amp circuit breaker, but you are correct that the cord is only 32 amps so a 40 amps breaker would be fine but something could be plugged into the outlet that draws 40 amps.



Wire sizes are #8 L1L2 and a #10 ground
 

RandyS

Active member
Joined
Apr 6, 2016
Messages
153
Location
San Diego
Tesla Owner
Model 3
Country
Country
#13
If you are trying to connect using the 120v adapter for the UMC, then all you need is a good solid 120v receptacle in the garage to plug into (screw terminal connections that are tight and no back-stab connections, etc.). It'll be on the slower side, at about 4-6 miles per hour of charging. But it will get the job done and many EV drivers charge this way.

If you want to charge at a faster rate, then you would think about having an electrician install a NEMA 14-50 receptacle, which would allow you to charge at 240 volts in a single family home or 208 volts in a condo or multi-family dwelling. In order to do this, you need physical space to install the new breaker in your panel, and electrical capacity in the panel to accommodate the new load. There are National Electrical Code (NEC) load calculations that an electrician should use to see if your panel can handle the new load.

And where I live in San Diego, you are supposed to get a City permit for adding the new NEMA 14-50 receptacle. Same with the City of Pomona...

Here is the link to the permit / information page for the City of Pomona:
http://www.ci.pomona.ca.us/index.php/forms-and-docs/building-safety

And here is the link to the electrical permit pdf:
http://www.ci.pomona.ca.us/mm/comde...I Need a Permit/ELECTRICAL PERMIT REQD-13.pdf
 

GDN

Moderator
Moderator
TOO Supporting Member
Joined
Oct 30, 2017
Messages
4,002
Location
Far North Dallas, TX
Tesla Owner
Model 3
Country
Country
#14
Trying to connect the 3 prong 110 v to the Nema 14-50.
Maybe I'm confused as well, but you unplug the 110 pigtail from the UMC and then plug in the 14-50 adapter. You can use either one and plug in to the appropriate outlet. The UMC and the car will know what kind of juice it is getting and adjust the charging properties. So until you get your 14-50 240 service installed in the garage, use the 110 and plug your car in. Once you get the upgraded plug, pull the pigtail out of the UMC and plug the 14-50 version in to it. Sorry if I've misunderstood, but I think several of us are confused about exactly what you are trying to do.
 

MelindaV

☰ > 3
Moderator
Joined
Apr 2, 2016
Messages
10,260
Location
Vancouver, WA
Tesla Owner
Model 3
Country
Country
#15
Joined
Oct 1, 2018
Messages
20
Location
Pittsburgh, PA
Country
Country
#16
Wowsers.

Anyhow, #6 for a 50 amp load on something that’s not a huge run. Protection device is for the wire size, so a 50a breaker on the panel. Neutral (not that it gets used) is sized the same as it is a current carrying conductor. I believe a #10 ground would suffice. Remember, neutral and ground are not the same! Never shall they touch except for their first meeting in the house!
Size for the receptacle, not the car! The car will take what it needs.
 

RocketRay

Well-known member
Joined
Jun 6, 2018
Messages
212
Location
SoCal
Tesla Owner
Model 3
Country
Country
#17
And where I live in San Diego, you are supposed to get a City permit for adding the new NEMA 14-50 receptacle. Same with the City of Pomona...
Same with the city of Cypress. I redid the entire panel since my ancient 100 amp Zinsco panel was full.
 

kyrral

Active member
Joined
Sep 29, 2018
Messages
65
Location
Pomona, CA
Tesla Owner
Model 3
Country
Country
#18
I guess where I am confused is how to unplug the 110v from the mobile charger. It looks like a single piece. How do I disconnect it?
 

kyrral

Active member
Joined
Sep 29, 2018
Messages
65
Location
Pomona, CA
Tesla Owner
Model 3
Country
Country
#20
GDN: My hero. 19 responses later I get an answer. but seriously, thanks all for the input.
rocket ray: how much for the panel? I've got something similar. Except mine is called a Sisco.
Is there a thread on "How many kilowatts to charge auto from zero?" So I can compute my electric cost?