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Tesla Wall Charger Installed - Some Tips

Got the Tesla wall charger installed at the cabin. Normally I would hire an electrician for anything beyond a light fixture install, but it is impossible to get any contractors to return a phone call let alone quote and complete a job in the Cascades right now. The good news is this is a pretty straightforward install for anyone who has a novice level of home wiring. I think it took me maybe 2 hours taking my time because...well...electricity :D A few tips that might help others:

1/ You only need 6/2 wire. Lots of threads say you need 6/3, but you don't. 6/2 will have the two hot leads you need plus a ground wire. I bought the 6/3 and ended up using the 3rd wire for ground and just trimming back the ground wire. Not only will 6/2 be cheaper (6/3 is about $5-$6 per foot right now), but a lot easier to work with as these are seriously stiff wires.
2/ Make sure you get the right breaker. I bought before looking and got the wrong one. Not tragic, but worth opening up your service panel and taking some pics prior.

I went from 5mi/hr on 110 to about 45 mi/hr. Plus the Tesla chargers look cool as hell :cool:
Screen Shot 2021-08-16 at 1.58.08 PM.png
 

ATPMSD

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I have read that 6/3 on a 60 amp breaker (to pull 48 amps) isn’t to code.

This statement is fairly common:

“While its common to use a 6-gauge wire for 60-amp breakers in practice, it's best to use a 4-gauge wire if you're installing a 60-amp subpanel. 60-amp breaker panels controlling several circuits can draw a max of 60 amps before the subpanel breaker trips.”

So 6-gauge is generally acceptable for a single wall connector Installation.
 

Sophias_dad

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I bought the 6/3 and ended up using the 3rd wire for ground and just trimming back the ground wire.
I'd wager that's actually not allowed, and the powers that be would have had you cap off the white and just used the ground as ground.

That exposed NMB is not really allowed, and 60 amps in #6 NMB is not allowed.

As another has pointed out, rear entry should have been used. Even as it stands, the nearest clamp/staple should be no more than 12" away from the fixture, and that clamp looks like its really close to 12"

Please tell me there's a cable clamp on top of that HPWC.
 
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This statement is fairly common:

“While its common to use a 6-gauge wire for 60-amp breakers in practice, it's best to use a 4-gauge wire if you're installing a 60-amp subpanel. 60-amp breaker panels controlling several circuits can draw a max of 60 amps before the subpanel breaker trips.”

So 6-gauge is generally acceptable for a single wall connector Installation.
Gen 3 installation guide says to use 6awg. Others can explain why better than me.
 
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Sophias_dad

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Gen 3 installation guide says to use 6awg. Others can explain why better than me.

Here's the actual line:
If installing for maximum power, use minimum 6 AWG, 90° C-rated copper wire for conductors.
NOTE: Upsize conductors if necessary.


Since NMB is only 60C rated, the idea that 6AWG NMB satisfies that requirement is incorrect. The terminals allow for #12 through #4 wire to connect, most likely so #4 NMB can be used if needed.
 
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EVer Hopeful

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Jul 7, 2021
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<pedantic>

Plus ...

You're supposed to "neatly wrap excess cord round the housing counter clockwise and secure the handle in the side dock" 😈

</pedantic>


btw, I second both of these sentiments from Trip McNealy "While we applaud your DIY effort and persistence to getting the job done, please please get a copy of the NEC (National Electric Code) book and read up the proper codes for wiring, breakers, and the like"
 
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Rocky_H

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At no point anywhere in this thread does the OP mention what size breaker/circuit this is. That is irritating anyway, but from the line about getting 45 mph of charging speed, that does seem to imply a 60A breaker setting.

That 6 gauge Romex cable is ABSOLUTELY NOT ALLOWED for a 60A circuit. You may switch that to a 50A breaker to get it back within safe limits.
 
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ATPMSD

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Mar 12, 2021
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This statement is fairly common:

“While its common to use a 6-gauge wire for 60-amp breakers in practice, it's best to use a 4-gauge wire if you're installing a 60-amp subpanel. 60-amp breaker panels controlling several circuits can draw a max of 60 amps before the subpanel breaker trips.”
I dug into this to understand it better, after all:
Gen 3 installation guide says to use 6awg. Others can explain why better than me.

Here is what I found. What the manual actually says is: “If installing for maximum power, use minimum 6 AWG, 90° C-rated copper wire for conductors.”

What is missed by many, including me, was that 90° C reference. Romex is rated at 60° C (and 55-amps) and is not what Tesla is referring too. Thus at a minimum, what is needed is 6 AWG THWN-2, THHN, XHHW-2, or USE-2 which is rated at 90° C, or the larger 4 AWG wire.

Always something to learn!
 

Rocky_H

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Feb 19, 2015
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Boise, ID
Here is what I found. What the manual actually says is: “If installing for maximum power, use minimum 6 AWG, 90° C-rated copper wire for conductors.”

What is missed by many, including me, was that 90° C reference. Romex is rated at 60° C (and 55-amps) and is not what Tesla is referring too. Thus at a minimum, what is needed is 6 AWG THWN-2, THHN, XHHW-2, or USE-2 which is rated at 90° C, or the larger 4 AWG wire.

Always something to learn!
Here is a comment from another thread that is all about this:


The Tesla install document is being kind of confusing there. They should have just said to use wire to meet code for the level of circuit you are going to use. Then there wouldn't be these confused arguments. Both THHN and Romex use 90 degree rated conductors, but you have to use them in accordance to their overall rating, which is lower for Romex because of how it's built/bundled.
 

Sophias_dad

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Here is a comment from another thread that is all about this:


The Tesla install document is being kind of confusing there. They should have just said to use wire to meet code for the level of circuit you are going to use. Then there wouldn't be these confused arguments. Both THHN and Romex use 90 degree rated conductors, but you have to use them in accordance to their overall rating, which is lower for Romex because of how it's built/bundled.
I gotta say, I really doubt 6 AWG NMB is hazardous if pushed to 48 amps continuous in >most< conditions. Its rated to 44 amps continuous anyway, and that extra 4 amps is only a 9% overload.

Looking further at the NEC temperature adjustment table, if ambient is 20-25C(68-77F), you are allowed to UPrate conductors by a factor of 1.08(aka 8%), taking that 44 amps to 47.52 amps. Since my particular application has essentially the entirety of my cable(minus less than a foot) in my 65f-year-round basement, I think I'm good. This may also be why my 50 amp breaker on that line is just fine supplying 48 amps for hours at a time and the temperature of the cable only gets up to 88f during said continuous charging session.

Would the insurance company pay if my house burns down as a result of an electrical fire? To justify not paying, they'd have to say it was the charging circut that overloaded, and the 50A breaker will probably live through the fire well enough to see its not a 60A breaker. But why take the chance, someday soon I'll go throttle it back to 40 amps. I'm charging maybe once a week these days, and could get by with a 120V line.
 
I'd wager that's actually not allowed, and the powers that be would have had you cap off the white and just used the ground as ground.
That is actually a really good question ... is it ok to do what the OP did (snip off the bare, and use the white as grounding), or is the proper thing to stick with the bare as the grounding conductor and just cap off the white inside the Wall Connector?
 

MY-Y

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Mar 4, 2020
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Wow…lively thread. Worth mentioning I am running through a 50A breaker. While it did spike to 45 mi/hr it settled to low 40s which is plenty fast. Also agree I need to clean up the cabling at the wall charger next time I get to the cabin.
Your low 40s MPH charge rate means that you are using the 48 amp setting. The HPWC is is a continuous load, so per the NEC, it needs a breaker rated for 48/80%=60A.

A 50 amp breaker allows a maximum of 50*80%=40A setting on the HPWC. 40A on the MY charges at ~35 MPH.
 

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