DIY mobile charger installation - NEMA 14-50 240V 50amp

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#1
Just wanted to share a video I made of my own DIY installation of a charging station for my new Model 3. It’s good for charging at up to 40 amps if your charger supports it. I took queues from other threads here while making material and installation decisions.

Here’s a link to the video on YouTube:

NOTE: Depending on your jurisdiction, you may need to take out a permit for an installation of this type. Also, your installation may differ so please use caution when making material and installation decisions.

Material used: 24’ 6 gauge 3-wire cable with ground, NEMA 14-50 receptical rated for 50 amps, metal wall box and cover, 50 amp two-pole circuit breaker, (2) 3/4” Romex connectors, nail plates, Sheetrock screws, joint compound.

Tools used: Reciprocating power saw, cordless power drill, corded stud and joist drill, 5/8 wood drill bit with extensions, multimeter, stick ruler, level, flathead and Phillips screw drivers, utility knife, wire strippers, stud finder, pencil.

T. Antony
 
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edittman1

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#2
So, my current challenge is that I bought the Tesla HPWC and wanted to run it at 60A to get the max 48A output. Unfortunately, I need to find a 60A quadplex, but they are either super uncommon or simply don't make them. Reason I have to do this is my panel may not have space to fit a standard 60A breaker (it takes up two too many slots).

If I go with a 50A breaker, is the max it can charge at 40A?
 

edittman1

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#3
Sorry - nice install btw! Surprised you cut across like that instead of going up high somehow and fishing back down through the ceiling or something. 6 of one, half dozen the other I guess.. Now you need to paint your walls. :)
 

slarty

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#4
So, my current challenge is that I bought the Tesla HPWC and wanted to run it at 60A to get the max 48A output. Unfortunately, I need to find a 60A quadplex, but they are either super uncommon or simply don't make them. Reason I have to do this is my panel may not have space to fit a standard 60A breaker (it takes up two too many slots).

If I go with a 50A breaker, is the max it can charge at 40A?
I put in a sub-panel a couple of years ago when I ran out, so when I added my charger, I just moved some lower amp ciruits onto the sub-panel. You could also add a couple of duplex breakers to free up a couple of slots, and then use a regular breaker for the charger.
 
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#5
So, my current challenge is that I bought the Tesla HPWC and wanted to run it at 60A to get the max 48A output. Unfortunately, I need to find a 60A quadplex, but they are either super uncommon or simply don't make them. Reason I have to do this is my panel may not have space to fit a standard 60A breaker (it takes up two too many slots).

If I go with a 50A breaker, is the max it can charge at 40A?
This is not code but you may find a good quality NEMA 14-50 can handle well above 50 amps. Plugs are designed to be unplugged which you should not be doing especially when charging. Make sure you run 60 amp wire. IF you do this be sure to test for heat. If the socket or plug gets warm you have a problem or lose wire. To be code compliant add a junction box and hard wire the charger in the junction.
 

96s46p

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#6
So, my current challenge is that I bought the Tesla HPWC and wanted to run it at 60A to get the max 48A output. Unfortunately, I need to find a 60A quadplex, but they are either super uncommon or simply don't make them. Reason I have to do this is my panel may not have space to fit a standard 60A breaker (it takes up two too many slots).

If I go with a 50A breaker, is the max it can charge at 40A?
Threadjacker! Just replace some other breakers with tandem to make room?
 
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#7
The important thing to note is that the charger doesn’t know what breaker you’re using. You certainly can use a 50 amp breaker, but it’s damn close to 48 amps. It may happen that your charger unexpectedly pulls 50 amps and your breaker will trip. It’s just too close. Plus, your outlet doesn’t know your breaker either. If you used an outlet rated for 50 amps, that too is very close to the 48 amp draw and runs the risk of failing.

For your wall connector installation, do yourself a favor and make sure EVERYTHING is rated for 60 amps. Also, make sure none of your components have a lower rating than your breaker. At minimum, equal to or higher.
 

garsh

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#8
You certainly can use a 50 amp breaker, but it’s damn close to 48 amps.
Yep. It is *safe* to use an underrated breaker, as its job is to protect the wiring from overheating and burning down your house. But you may end up tripping it during normal use if you try to charge at 48 amps.
 

Dano9258

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#9
I'm about to do the same thing. I have to go about 35' and an going to run the cable from the main panel using 6/3 wire, up into the ceiling space (lay it on the rafters across) and then down to the outlet. Since you did this already, any good tips to follow?
 

edittman1

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#10
That was my suggestion as well, versus cutting all along the side of the wall and making those holes, as the OP did. Probably works out to similar effort because coming down you'll encounter some cross braces in the framing and need to put holes in those too I'd assume..

For everyone else above, I used 6/3 and have the HPWC and will put it on the "9" setting which limits it to 60A output. If I did the 50A breaker, I would adjust the HPWC to the 50A setting which is the "8" I believe. Guess I could try it on the "9" and see what happens, the wire is sufficient and the HPWC will cover it. Just very probable that it will trip the breaker IMO, there apparently needs to be overhead..
 

garsh

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#11
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#12
I'm about to do the same thing. I have to go about 35' and an going to run the cable from the main panel using 6/3 wire, up into the ceiling space (lay it on the rafters across) and then down to the outlet. Since you did this already, any good tips to follow?
That was my suggestion as well, versus cutting all along the side of the wall and making those holes, as the OP did. Probably works out to similar effort because coming down you'll encounter some cross braces in the framing and need to put holes in those too I'd assume..

For everyone else above, I used 6/3 and have the HPWC and will put it on the "9" setting which limits it to 60A output. If I did the 50A breaker, I would adjust the HPWC to the 50A setting which is the "8" I believe. Guess I could try it on the "9" and see what happens, the wire is sufficient and the HPWC will cover it. Just very probable that it will trip the breaker IMO, there apparently needs to be overhead..
Thing is I’m not much of a fisherman, let alone an electrician. I considered going up, but all the ceiling joists run perpendicular to the direction I was going. Plus it’s 10 feet up. I either would have had to punch all those joists or I’d fish the wire above the joists and not have a good way to anchor down the wire properly without taking down a bunch of Sheetrock. Remember, you’ll have an inspector to please. Right!? :)

Few things I might suggest to anyone taking this on:
1. Take the shortest path possible if it’s reasonable. 6/3 wire is expensive. It’s also hard as hell to work with in tight spaces. However, if there’s a longer path which makes your life dramatically easier, then by all means go that way.
2. When finally in the junction box, leave the cut wires as short as possible with room enough to make it into your appliance/outlet and not a lot more. Again, that 6/3 wire doesn’t want to bend so having extra to tuck into the box is near impossible.
3. I don’t show it in the video, but if punching through studs, make sure you bang in some nail plates before replacing the Sheetrock pieces.

T. Antony
 

ADK46

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#13
Running conduit is not difficult except for choosing the fittings you need at the store. And you need to strategize over pulling the wires - there are special fittings known as "pull boxes" for corners, etc. Being individual wires, you don't have to wrestle with cable - #6 is easy (requires 3/4" conduit, or "EMT" as the steel version is called). I might have used #3 (1" conduit required) for future-proofing to 100 amps, but that stuff is pretty stiff. If you're just aiming for a charging circuit (Wall Connector or 240V socket (not 240/120V, not 14-50), you don't need the neutral, so you're buying less copper. The ground wire can be smaller than the others - if I recall correctly, #10 if the red and black are #6.

I should have used 1" conduit - the Wall Connector expects it, and it would have allowed me to replace the #6 with #3 someday.

Conduit might be a bit unsightly, but it sure looks safer (and you actually can see and feel it) compared to something buried in a wall, where only your nose will tell you something is wrong. Every situation is different, though. I'm just saying conduit is an option to consider, even for DIY.
 
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#14
Running conduit is not difficult except for choosing the fittings you need at the store. And you need to strategize over pulling the wires - there are special fittings known as "pull boxes" for corners, etc. Being individual wires, you don't have to wrestle with cable - #6 is easy (requires 3/4" conduit, or "EMT" as the steel version is called). I might have used #3 (1" conduit required) for future-proofing to 100 amps, but that stuff is pretty stiff. If you're just aiming for a charging circuit (Wall Connector or 240V socket (not 240/120V, not 14-50), you don't need the neutral, so you're buying less copper. The ground wire can be smaller than the others - if I recall correctly, #10 if the red and black are #6.

I should have used 1" conduit - the Wall Connector expects it, and it would have allowed me to replace the #6 with #3 someday.

Conduit might be a bit unsightly, but it sure looks safer (and you actually can see and feel it) compared to something buried in a wall, where only your nose will tell you something is wrong. Every situation is different, though. I'm just saying conduit is an option to consider, even for DIY.
You’re completely right. I considered using conduit, but I had never worked with it before so really it was just a comfort thing. Plus, I didn’t know how to handle the transition from inside the wall (near the breaker) to outside the wall. I’m sure there’s a fitting for it, but I didn’t know where to start. I figured the panel is in the wall, the outlet box is in the wall, thus no transitions. But you’re completely right. Conduit, once mounted, would’ve made pulling/feeding the wire through a cake walk.

And you’re also right about not needing the common wire. I learned that after the fact.

Thanks for your input.

T. Antony
 

Dan D

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#16
Plus, I didn’t know how to handle the transition from inside the wall (near the breaker) to outside the wall. I’m sure there’s a fitting for it, but I didn’t know where to start.
I have a picture of this coming for you. As soon as Mrs Dan D can get out of bed and text it to me.
 

Dan D

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#17
You'll need to do it like this:

1543501411718-png.18296


1543501445249-png.18297


The 'breakout' on the right goes to my 30-amp plug for the car. The one on the left goes to my transfer switch for my stand-by generator. These were done by 2 different electricians.
 

ADK46

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#18
You can avoid forming the slight bend in the conduit above the box with a fitting that has an offset to it. At least, that's what I found for some other job involving 1/2" conduit.

offsetboxfitting-jpg.18301