DIY Install of NEMA 14-50 receptacle

[kevinf1990]

I hope to be taking delivery of a Tesla Model Y performance in the coming weeks. During the wait, I have done a lot of research regarding the charging infrastructure and read through the NEMA 14-50 master thread in the Model 3 forums. I have done some electrical work myself and I am starting this thread more to validate my thoughts or have my thoughts critiqued on how the outlet should be installed.

We just recently moved to a new construction townhouse which is pre-wired for EV charging. I just need to install the receptacle and the breaker. The preinstalled box and the circuit breaker are within about 3-4 ft from each other. I just got to removing the circuit breaker panel and the prewired receptacle box and saw that the wiring is aluminum (at least that's what I think it is, the wires inside were silver). This is not what I expected and was expecting it to be copper. Based on my wire gauge measurement, it appears to be 6 awg. I plan to buy a 40A breaker as I am only going to be using the UMC for now with a NEMA 14-50 receptacle. I don't want to get 50A because the UMC does not pull that much current and I don't want to have too much overhead before the breaker trips in case of any issues.

Do you guys think it would be feasible to electrical tape an end of copper Romex 6/3 cable to one end of the existing aluminum wire and pull it through to replace to copper? That way I don't need to open the dry wall to replace the cable. I would also be able to use the Hubbell/Bryant commercial grade receptacle. Or should I just get a Cooper 5754N receptacle which accepts AL wiring? Is there anything else I should watch out for in terms of the AL wiring?

Any advice or suggestions are appreciated.

 

[Mateo83]

I would think if you tape it good you could pull it through. If there are a lot of elbows or junctions it may be a hard pull.

 

[howardnj]

I hope to be taking delivery of a Tesla Model Y performance in the coming weeks. During the wait, I have done a lot of research regarding the charging infrastructure and read through the NEMA 14-50 master thread in the Model 3 forums. I have done some electrical work myself and I am starting this thread more to validate my thoughts or have my thoughts critiqued on how the outlet should be installed.

We just recently moved to a new construction townhouse which is pre-wired for EV charging. I just need to install the receptacle and the breaker. The preinstalled box and the circuit breaker are within about 3-4 ft from each other. I just got to removing the circuit breaker panel and the prewired receptacle box and saw that the wiring is aluminum (at least that's what I think it is, the wires inside were silver). This is not what I expected and was expecting it to be copper. Based on my wire gauge measurement, it appears to be 6 awg. I plan to buy a 40A breaker as I am only going to be using the UMC for now with a NEMA 14-50 receptacle. I don't want to get 50A because the UMC does not pull that much current and I don't want to have too much overhead before the breaker trips in case of any issues.

Do you guys think it would be feasible to electrical tape an end of copper Romex 6/3 cable to one end of the existing aluminum wire and pull it through to replace to copper? That way I don't need to open the dry wall to replace the cable. I would also be able to use the Hubbell/Bryant commercial grade receptacle. Or should I just get a Cooper 5754N receptacle which accepts AL wiring? Is there anything else I should watch out for in terms of the AL wiring?

Any advice or suggestions are appreciated.

Kevin
My MY is on order with a EDD now May 31st to June 28th 2022.
My HPWC was installed yesterday in my garage with roughly 150 ft of #2 Aluminum 4 conductor cable from my 200 Amp breaker panel in my basement. I decided to use a Tesla recommended electrician and am very glad that I did. I have a 125 amp sub panel in my garage. Although a 100 amp sub panel was in the estimate I guess they were out of stock so I ended up with a 125 amp 12 slot sub panel with a double 60 amp breaker. A permit was applied for and I'm sure their excellent neat and professional work that they did will pass inspection.
As someone pointed out in another thread if those that do the work themselves with no permit, no licensed electrician, and if there is ever a fire the insurance company will most likely deny a claim?
I decided that I was unwilling to take any chances. My nephew will be stopping by next week with his 2021 MY so I can test out my wall charger to confirm the promised 48 amp charge rate prior to my Delivery DD.

 

[roblab]

It's possible that the aluminum wire is stapled somewhere, too. I hope not, but it's a possibility. I think you should try for the copper, though. I, too, have electrical experience and wired my garage for charging, If you know what you are doing, there's no need to hire an "electrician" several hundred dollars to do what can be done easily. My daughter's house was similar to your situation, and I wired the 14-50 easily, and it works well after several years. My own garage outlet works perfectly after a dozen years. There is no magic in having an electrician pull a wire and screw it to an outlet.

Where I live, the county allows homeowners to do their own wiring of outlets.

 

[chnry]

I hope to be taking delivery of a Tesla Model Y performance in the coming weeks. During the wait, I have done a lot of research regarding the charging infrastructure and read through the NEMA 14-50 master thread in the Model 3 forums. I have done some electrical work myself and I am starting this thread more to validate my thoughts or have my thoughts critiqued on how the outlet should be installed.

We just recently moved to a new construction townhouse which is pre-wired for EV charging. I just need to install the receptacle and the breaker. The preinstalled box and the circuit breaker are within about 3-4 ft from each other. I just got to removing the circuit breaker panel and the prewired receptacle box and saw that the wiring is aluminum (at least that's what I think it is, the wires inside were silver). This is not what I expected and was expecting it to be copper. Based on my wire gauge measurement, it appears to be 6 awg. I plan to buy a 40A breaker as I am only going to be using the UMC for now with a NEMA 14-50 receptacle. I don't want to get 50A because the UMC does not pull that much current and I don't want to have too much overhead before the breaker trips in case of any issues.

Do you guys think it would be feasible to electrical tape an end of copper Romex 6/3 cable to one end of the existing aluminum wire and pull it through to replace to copper? That way I don't need to open the dry wall to replace the cable. I would also be able to use the Hubbell/Bryant commercial grade receptacle. Or should I just get a Cooper 5754N receptacle which accepts AL wiring? Is there anything else I should watch out for in terms of the AL wiring?

Any advice or suggestions are appreciated.

#6 aluminum is rated for 40 amps. With your box being so close to the panel you should be fine using the mobile charger without changing the wiring.
Trying to pull a wire through will be hard and you may even damage the wire without knowing since it's behind the wall.

 

[kevinf1990]

Besides the Cooper outlet, are there any other commercial rated receptacle that will work with aluminum? I think with aluminum, I will need anti-oxidizing paste as well?

 

[MDElectric]

As someone pointed out in another thread if those that do the work themselves with no permit, no licensed electrician, and if there is ever a fire the insurance company will most likely deny a claim

I wish people would stop using this speculative comment to scare people into getting a licensed electrician and permits. You should definitely get a permit, but even if you don't and there's fire damage, your insurance will likely cover you just like they'll cover you for deep frying that turkey in your garage. They cover damage from incompetence all the time. They may not keep you as a policyholder, but I don't see any reference to non-permitted work in my homeowners policy. If you DIY your install, pay for the permit, not because of insurance considerations, but because you value your life, those of your family, and the lives of future owners of your property.

 

[chnry]

Besides the Cooper outlet, are there any other commercial rated receptacle that will work with aluminum? I think with aluminum, I will need anti-oxidizing paste as well?

Most new outlets are rated for both copper and aluminum wires.
It doesn't hurt to use the paste

 

[OxBrew]

Most new outlets are rated for both copper and aluminum wires.
It doesn't hurt to use the paste

It is required to use the paste, within a few seconds of carefully cleaning the bare wire to remove oxidation, with a wire brush or special tool.

If it's only 3-4 ft, it should be easy to swap to copper. I agree, there could be a staple in there, but likely it just runs through a hole in one stud, if the heights are about the same. I'd try pulling it.

If that's impossible, then cut out some squares in the drywall. Not a huge deal to repair it.

 

[kevinf1990]

Most new outlets are rated for both copper and aluminum wires.
It doesn't hurt to use the paste

Which outlets are you referring to. Seems like the Hubbell and Bryant are out of the question since they only accept copper

 

[ATPMSD]

I plan to buy a 40A breaker as I am only going to be using the UMC for now with a NEMA 14-50 receptacle.

I suggest you consider the Wall Connector instead, the 14-50 is not as cheap was you might think. A quality outlet will run you about $80, you need a GFIC breaker that adds $100+, and you need to order a 14-50 adpater for the mobile connector, another $45. Add in some sort of cable management system for say $30 and your total is $255. The Wall Connector is $550 + a $10 breaker, which makes the total just $300 more. What do you get for that extra $300

1. The ability to charge at 48A (on a 60-amp circuit) instead of 32A
2. You get to keep the mobile connector in the car so it is not forgotten when needed
3. If you add a 2nd Wall Connector at a later date, power sharing is already built in
4. Firmware updates to the connector, power sharing was recently added via a firmware update

And I would definatly replace the wire with copper!

If you stay with your plan to run 40-amps to a 14-50 outlet, be sure to lable the outlet as 40-amps

 

[kevinf1990]

I suggest you consider the Wall Connector instead, the 14-50 is not as cheap was you might think. A quality outlet will run you about $80, you need a GFIC breaker that adds $100+, and you need to order a 14-50 adpater for the mobile connector, another $45. Add in some sort of cable management system for say $30 and your total is $255. The Wall Connector is $550 + a $10 breaker, which makes the total just $300 more. What do you get for that extra $300

1. The ability to charge at 48A (on a 60-amp circuit) instead of 32A
2. You get to keep the mobile connector in the car so it is not forgotten when needed
3. If you add a 2nd Wall Connector at a later date, power sharing is already built in
4. Firmware updates to the connector, power sharing was recently added via a firmware update

And I would definatly replace the wire with copper!

If you stay with your plan to run 40-amps to a 14-50 outlet, be sure to lable the outlet as 40-amps

I thought about it but wasn't sure because we are on a 125A service and the big appliances that uses electricity are the AC and oven. If I were to get a wall connector, I would have to spend money to get it installed as well. Drywall would need to be opened up as well. So overall installing the wall connector would be much more expensive for me. Don't get me wrong, I would love to . But I don't think our situation allows for it at the moment.

 

[ATPMSD]

I thought about it but wasn't sure because we are on a 125A service and the big appliances that uses electricity are the AC and oven. If I were to get a wall connector, I would have to spend money to get it installed as well. Drywall would need to be opened up as well. So overall installing the wall connector would be much more expensive for me. Don't get me wrong, I would love to . But I don't think our situation allows for it at the moment.

Yeah, 125A service does limit you. But except for item 1, all of the other advantages apply if that matters to you, the Wall Connector can be set to anything from a 15A to 60A circuit. BTW, if you plan to buy a 2nd mobile connector to keep in the car, then definitely install the wall connector as the price for the 14-50 option just went to $500.

Good luck and enjoy the car!

 

[howardnj]

I wish people would stop using this speculative comment to scare people into getting a licensed electrician and permits. You should definitely get a permit, but even if you don't and there's fire damage, your insurance will likely cover you just like they'll cover you for deep frying that turkey in your garage. They cover damage from incompetence all the time. They may not keep you as a policyholder, but I don't see any reference to non-permitted work in my homeowners policy. If you DIY your install, pay for the permit, not because of insurance considerations, but because you value your life, those of your family, and the lives of future owners of your property.

MDElectric
I was not trying to scare anyone!
I have learned many things in reading posts on this site. I have also learned many things just from life experiences. Being able to charge an electric vehicle at 240v @48 amps is quite a power draw. 1.920kw according to my math.
Every local electric code is different and those that choose to do their own work should be sure they are up to date on those codes in my opinion. A few examples that I learned by speaking to a Tesla recommended electrician.
In my location:
1- All electrical panels must be installed on a plywood backboard.
2- All backboards must be painted black. I don't see that in my local Home Depot but they are available in the local electrical supply house where the electricians obtain their supplies
3- # 2 Aluminum 4 conductor cable is a superior choice for a 125 ft run from a 200 amp basement panel to a 100 amp garage sub panel as aluminum cable is much lighter and easier to work and cheaper than with copper cable and meets the current local electrical code.
4- Proper staples, 100 amp, 60 amp breakers and proper terminations are required to pass local building inspections and on and on.

The Tesla recommended electrician also told me that over 75% of their current jobs are installing EV chargers. They are fully aware of what the local inspectors look for during inspections.
Although many on this site feel they can save a considerable amount of money by doing the work themselves.
Personally I ran almost all of the electrical cable many years ago when our basement was being finished,
I felt that I would leave this job to the pros and I'm happy that I did. They did an excellent very neat job and I'm excited to receive my MY later this year. My nephew who already has his MY will be stopping by this coming week to test out my new charger while I wait for my VIN and delivery.

 

[ATPMSD]

240v @48 amps is quite a power draw. 1.920kw according to my math

240v * 48 amps = 11,520 watts or 11.52 kW

 

[howardnj]

240v * 48 amps = 11,520 watts or 11.52 kW

You are correct! Sorry for my math error

 

[SilverString]

I wish people would stop using this speculative comment to scare people into getting a licensed electrician and permits. You should definitely get a permit, but even if you don't and there's fire damage, your insurance will likely cover you just like they'll cover you for deep frying that turkey in your garage. They cover damage from incompetence all the time. They may not keep you as a policyholder, but I don't see any reference to non-permitted work in my homeowners policy. If you DIY your install, pay for the permit, not because of insurance considerations, but because you value your life, those of your family, and the lives of future owners of your property.

I agree @MDElectric, the FUD principal at work. It runs rampant in these types of posts. On the other hand, if it makes the owner happy and feel safer then there is some value in it, reasonable or not. The simple fact of the mis-calculated kW draw is evidence that some people should not be doing their own installs. I have to admit it is a beautiful install, and is it not possible if that backboard were painted white instead of black that his house could still burn down?

 

[e645824]

I installed this in my barn as a backup/alternative to my existing Tesla Wall Connector that is on my home:

https://www.amazon.com/dp/B08549S8KK​

https://www.amazon.com/dp/B000BOCBCA​

https://www.evseadapters.com/products/nema-14-50-adapter-for-tesla-model-s-x-3-gen-2/​

Since my Tesla Wall Connector is "smart", I also wanted something "dumb" as a backup just in case.

Also, as the Amazon reviews indicate the box I bought is a pain because it doesn't have knock-outs. I had a metal hole saw so it wasn't a problem. But if you don't, then be aware that those knock-out looking indentations aren't actually knockouts.

I'm happy with the box and the included receptacle. The receptacle is rated for up to 4 AWG wire and accepts aluminum or copper. Since I had a short 1-foot run of aluminum wire already in-place, I just cleaned the ends and used the goo (instead of replacing with copper).

I installed this box a foot away from my barn's breaker panel -- it already had a length of 4 AWG aluminum wire running to an old-style 240V 50A welder receptacle which I removed and replaced with this box. And I added a ground wire since the old receptacle was hot-hot-neutral while this 14-50 also has a ground. Since this was off of a secondary panel in my barn, neutral and ground are not tied together (they are tied together back at the main breaker panel). Note that Tesla only uses three of the four wires (i.e. the Tesla Wall Connector uses hot-hot-ground with 240 volts) but I'm not sure if this 14-50 adapter from EVSE actually uses 3-wire or 4-wire. But I wired the 14-50 correctly for 4-wire regardless in case I ever want to plug something else into that receptacle in the barn.

Scott

--

MYLR | Red ext | White int | 19" | 5 seats | tow | no FSD | made/delivered Oct 2021

 

[WADan]

It's possible that the aluminum wire is stapled somewhere, too. I hope not, but it's a possibility. I think you should try for the copper, though. I, too, have electrical experience and wired my garage for charging, If you know what you are doing, there's no need to hire an "electrician" several hundred dollars to do what can be done easily. My daughter's house was similar to your situation, and I wired the 14-50 easily, and it works well after several years. My own garage outlet works perfectly after a dozen years. There is no magic in having an electrician pull a wire and screw it to an outlet.

Where I live, the county allows homeowners to do their own wiring of outlets.

I concur. i did it myself and it passed the inspection no problem!

 

[Rocky_H]

We just recently moved to a new construction townhouse which is pre-wired for EV charging.

That's cool. A lot of states are requiring some kind of pre-wire for EV charging.

The preinstalled box and the circuit breaker are within about 3-4 ft from each other. I just got to removing the circuit breaker panel and the prewired receptacle box and saw that the wiring is aluminum (at least that's what I think it is, the wires inside were silver). This is not what I expected and was expecting it to be copper.

Oh jeez. That is weird. Using aluminum can make sense if there is significant cost savings because of a really long run, like over 100 feet. But for less than 5 feet is stupid because it's more troublesome to deal with for almost no cost savings. You have to use the anti-oxidation paste, and some receptacles aren't allowed to use AL wire, etc. Blech. If you can re-pull copper in there, that would be nice.

I thought about it but wasn't sure because we are on a 125A service and the big appliances that uses electricity are the AC and oven.

But there's no difference. The wall connector is a variable setting device. An outlet on a 40A circuit or the wall connector on a 40A circuit are exactly the same load. The wall connector can be configured for as low as 15A circuits.

If I were to get a wall connector, I would have to spend money to get it installed as well.

Huh? Why? Some people would do an electrician for either, but if you're willing to do the outlet yourself, the wall connector isn't much different.

Drywall would need to be opened up as well.

What? No it wouldn't. It would attach onto the ends of those same wires--no opening the wall needed. You just hang the wall connector on the surface over that junction box or next to it if it's sticking out of the surface.

So overall installing the wall connector would be much more expensive for me.

The installation part shouldn't be any more expensive at all. As @ATPMSD was mentioning, though, doing the outlet has a few extra costs of the really expensive breaker, the Tesla cord plug adapter, and the outlet itself that make for not much cost savings anymore. It's maybe just a few hundred dollars for the cost of the wall connector unit.