Tesla Wall Connector: Hard wiring Vs NEMA 14-50

[ajexpert]

I’ve my Tesla Model Y delivery date finalized and now I’m exploring the options for charging. I ordered Tesla Wall Connector and thinking to connect to NEMA 14-50 for flexibility. Appreciate if I get response to following questions.

• I understand that 60 Amp hard-wired wall connector works best, however, what are the cons of installing NEMA 14-50 with 50 Amp wire? Appreciate if someone let me know how slow the charging will be if Tesla Wall Connector is connected to NEMA 14-50 (50 Amp)
• Assuming I opt for NEMA 14-50, would it affect the installation rebate or any State/Federal(?) rebate? One electrician said if I do not opt for hard wiring, the rebate can be denied. Is it true?
• Any EV rebates available to apply for state of MD (Montgomery County)?

TIA

 

[Sun&moon]

Actually this has been mentioned a lot, but the forum is huge so not easy to find. Here's a thread for example:
NEMA 14-50 vs 6-50
Most people go with a 14-50 because that is the most universal solution (most J1772 EVSEs also have 14-50 options, but 6-50 seems to be rare).

Here in Bay Area, electricians that pre-wire a garage for a EVSE installs a 14-50, I have never seen a 6-50.

Thank you.

 

[stopcrazypp]

Wall connector is also safer and can charge faster (48 amps vs 32). For a permanent home charging install a hard wired wall connector is the best solution. I have seen to many melted plugs and receptacle over the years. They are fine for occasional use or even frequent as a temporary but it's not a good long term solution to use the mobile connector.

Around here most new construction install wiring (no receptacle) for the EV charger. They advertise it as a "rough in for EV charger". These receptacle were never designed for the sustained continuous high load of EV charging. Eventually the contacts will wear out resulting in arcing, melting, burning, and possibly properly damage. Then there are the plugs mostly manufactured overseas with poor QC. Skip all that and hard wire the wall connector is my suggestion.

I am all for saving money and I think you will find the hard wired setup may actually be the same or less and provide the benefits and piece of mind mentioned above.

On the receptacle side, almost all of the failed ones I see mentioned on the forums are the Leviton ones given it only has half a contact on the prongs (and it uses screws to secure the wires), although some people have used one for years with no problems. With the Bryant or Hubbell with the v shaped wire clamps, the connection is much more secure. Given the plug is almost permanently connected and rarely disconnected, there shouldn't be much if any mechanical wear on them.

As for defective 14-50 plugs, I have seen this on the wall charger with 14-50 pigtail (which Tesla discontinued). For the 14-50 adapter however for the Mobile Connector, it seems to be fairly well made and it has temperature detection, so it's quite rare for the plug to fail.

 

[R.C.]

I am adding new wiring to my garage (40amp) and wanted to add a 50a outlet to which I'd plug-in my walk charger (with a pigtail). In this way, if I wanted to use the outlet for something else, I'd have to un plug the wall charger. I see this as ideal but, if there is something wrong with doing this and/or rebate would be in jeopardy, I'd definitely go back to hardwire.

 

[exxxviii]

I am adding new wiring to my garage (40amp) and wanted to add a 50a outlet to which I'd plug-in my walk charger (with a pigtail). In this way, if I wanted to use the outlet for something else, I'd have to un plug the wall charger. I see this as ideal but, if there is something wrong with doing this and/or rebate would be in jeopardy, I'd definitely go back to hardwire.

You can always convert a 60A hardwire circuit into a 14-50 outlet circuit. It is difficult to go the other way. What else do you think would ever use a 14-50 outlet other than an EV charger? If nothing comes to mind, then I would wire for 60A hardwire and down-convert it to 14-50 if that day ever comes.

 

[R.C.]

You can always convert a 60A hardwire circuit into a 14-50 outlet circuit. It is difficult to go the other way. What else do you think would ever use a 14-50 outlet other than an EV charger? If nothing comes to mind, then I would wire for 60A hardwire and down-convert it to 14-50 if that day ever comes.

I was thinking arc welder but very rarely are the key words. I agree, will hard wire and IF I need to do a little welding, I can change for that event. I am limited to 40a or 30mph. Initially 30a or 22mph until I change existing wiring in house from 10 to 8awg. A 40a breaker is the largest I care to allocate on my 100a service panel.

 

[davewill]

You can always convert a 60A hardwire circuit into a 14-50 outlet circuit. It is difficult to go the other way. What else do you think would ever use a 14-50 outlet other than an EV charger? If nothing comes to mind, then I would wire for 60A hardwire and down-convert it to 14-50 if that day ever comes.

Why is going the other way difficult? Even, if you only used 50a capable wiring, you can still do it, you just have to set the Wall Connector for a 50a circuit. One of my EVSEs is on a 40a circuit with a 6-50. If it ever dies, I'll probably put a Wall Connector in it's place. I'll just have to get a different outlet cover and the appropriate jacketed pigtail, and set the WC for 32a charging. No sweat.

 

[stopcrazypp]

I am adding new wiring to my garage (40amp) and wanted to add a 50a outlet to which I'd plug-in my walk charger (with a pigtail). In this way, if I wanted to use the outlet for something else, I'd have to un plug the wall charger. I see this as ideal but, if there is something wrong with doing this and/or rebate would be in jeopardy, I'd definitely go back to hardwire.

If you are going this route, I would spend the extra to use wiring capable of 50A or 60A (or if you are on a budget you can go with a 6-50 to save a conductor). I think you will regret adding in 40A wiring because it limits your flexibility a lot more.

 

[R.C.]

If you are going this route, I would spend the extra to use wiring capable of 50A or 60A (or if you are on a budget you can go with a 6-50 to save a conductor). I think you will regret adding in 40A wiring because it limits your flexibility a lot more.

Agree, although I will start by adding 8awg THHN thru conduit from existing 30a ckt (10awg NMB) and set wall at 30A. My upgrade will involve changing wiring in house (to CB) to 6awg NMB and that combination should be good for 55a. CB size would be next decision (50 or 60) and since I only have 100a service, I'd better do a load analysis to see if any "upgrade" is possible without first upping the service. It seems my overall length may be an issue so that's another reason to go directly to the wall-charger and put it in with the minimal "extra" wire length. I originally thought routing another 25 ft to a central point would be the plan but Telsa has a 24 ft cord on the wall that could be situated to hang down where I'd want use it OR to the other garage spot.

 

[R.C.]

Actually to use 6awg and go to a 50a breaker I still only get 37 MPH vs 30MPH (with 8awg and 40a breaker).
Starting out with some 10awg and 30a breaker for 22MPH. Guess I'd have to compare cost of 6 & 8 wire,
but another option would be use 40a breaker even if I use 6awg and set wall-charger for 40a (30MPH).
Then I'd be in a position to notch it up (to 50a breaker and 27 MPH) IF/WHEN I get a service upgrade.

 

[exxxviii]

Why is going the other way difficult? Even, if you only used 50a capable wiring, you can still do it, you just have to set the Wall Connector for a 50a circuit. One of my EVSEs is on a 40a circuit with a 6-50. If it ever dies, I'll probably put a Wall Connector in it's place. I'll just have to get a different outlet cover and the appropriate jacketed pigtail, and set the WC for 32a charging. No sweat.

Because if you install a true 50A circuit, you would probably need to replace the wiring. Plus, you might not have the length to hardwire if you put the outlet on the wall based on the different location of the charger.

 

[Jblache]

Use #6 2 strand with a ground. It is about $7.00 per foot. Put a 50 amp breaker in. I charge at just 25 amps to conserve battery.

You don’t need a 50 amp breaker if you are charging at 25 amps. 10 amp buffer is the recommendation. 25 amp is awfully slow. Might want to think about that. I would not hamstring myself with Tesla charger. Go for Charge Point. Highly rated and can charge at 40 amps with 14-50 plug-in. 50 amps hardwired. I went with 14-50 plug-in for flexibility if I move. Lot of ways you can go. Good luck!

 

[davewill]

Because if you install a true 50A circuit, you would probably need to replace the wiring. Plus, you might not have the length to hardwire if you put the outlet on the wall based on the different location of the charger.

Why would you replace the wiring? You would just use a pigtail to wire the WC and set it for a 50a circuit..

 

[exxxviii]

Why would you replace the wiring? You would just use a pigtail to wire the WC and set it for a 50a circuit..

Are you being pedantic, or did you not read my original post? If you told an electrician to install a 50A circuit, the wiring would be undersized for 60A. So, you would have to replace it to make it a 60A circuit. Thus it would be easier to convert a 60A hardwire circuit to a 50A 14-50 that it would be to convert a 50A 14-50 to 60A hardwire.

 

[davewill]

Are you being pedantic, or did you not read my original post? If you told an electrician to install a 50A circuit, the wiring would be undersized for 60A. So, you would have to replace it to make it a 60A circuit. Thus it would be easier to convert a 60A hardwire circuit to a 50A 14-50 that it would be to convert a 50A 14-50 to 60A hardwire.

There is no need to upgrade to 60a. Your posts made it sould like you couldn't install a wall connector where a 14-50 had been.

 

[exxxviii]

There is no need to upgrade to 60a. Your posts made it sould like you couldn't install a wall connector where a 14-50 had been.

I recommended that he wire for 60A hardwire and down-convert it to 14-50 if that day ever comes. That is the best of everything, if he may not need a 14-50 outlet.

 

[jcanoe]

I am adding new wiring to my garage (40amp) and wanted to add a 50a outlet to which I'd plug-in my walk charger (with a pigtail). In this way, if I wanted to use the outlet for something else, I'd have to un plug the wall charger. I see this as ideal but, if there is something wrong with doing this and/or rebate would be in jeopardy, I'd definitely go back to hardwire.

Your first sentence assumes that it is OK to add a plug to the Tesla Gen3 Wall Connector. This modification would not be code compliant.

Do it right the first time so that you minimize future expenses. This could even mean installing an 80A or 100A sub panel in the garage knowing that you will be upgrading the 100A service panel in the future, else

Have the electrician install wire for a 240V/60A charging circuit and install the Tesla Wall Connector. Although the wire would be rated for 60A the circuit breaker would be 40A; the Wall Connector would have to be set (for now) for a 40A circuit. Per the Tesla Gen3 Wall Connector installation manual adding a GFCI circuit breaker is neither required or recommended (this would save up to ~$130.)

14-50R versus 6-50R

The 14-50 receptacle (in the garage or outdoors) could be used to provide power to a good size RV motor home; also for EV charging. If the application is for EV charging then a GFCI circuit breaker would be required. If the application is to power an RV motor home then the electrician would not install a GFCI circuit breaker (GFCI is not compatible with an RV.)

I believe the 6-50 receptacle is more common than 14-50 for welding equipment. The 6-50 receptacle does not use the neutral connection so this would slightly reduce the cost of the wire (but not change the installation cost.)

 

[Eric33432]

My son installed a Tesla Wall Connector for his M3P and his girl friend's M3 rear wheel drive using #6 THHN (#10 THHN for the ground) in 3/4" PVC conduit all the way from his electrical pane to the TWCl, but on a 50 amp breaker (with TWC set appropriately), just because he had an unused 50 amp breaker left in the panel from when he had some remodeling done. Routinely, the two of them charge on alternate nights. He was planning to buy a 60 amp breaker to replace it but never did because he found that every morning the car that was being charged that night was fully charged and just left it using the 50 amp breaker / 40 amp charging.

At my house I have two TWC's installed with 60 amp circuits (breakers and #6 THHN (one in conduit and one using MC cable)) because they were new installs. I understand why some would reuse existing wiring that is adequate for their charging needs, but why anyone would not install a new circuit, using #6 THHN (conduit or MC) for a 60 amp circuit / 48 amp charging is beyond me, as the cost difference is usually trivial, or at a minimum install a 50 amp circuit using #6 NM-B if conduit or MC cable is something they do not want to use.

Unless running a circuit more than about 150 feet, there is no need to upsize the conductors.

 

[h2ofun]

My son installed a Tesla Wall Connector for his M3P and his girl friend's M3 rear wheel drive using #6 THHN (#10 THHN for the ground) in 3/4" PVC conduit all the way from his electrical pane to the TWCl, but on a 50 amp breaker (with TWC set appropriately), just because he had an unused 50 amp breaker left in the panel from when he had some remodeling done. Routinely, the two of them charge on alternate nights. He was planning to buy a 60 amp breaker to replace it but never did because he found that every morning the car that was being charged that night was fully charged and just left it using the 50 amp breaker / 40 amp charging.

At my house I have two TWC's installed with 60 amp circuits (breakers and #6 THHN (one in conduit and one using MC cable)) because they were new installs. I understand why some would reuse existing wiring that is adequate for their charging needs, but why anyone would not install a new circuit, using #6 THHN (conduit or MC) for a 60 amp circuit / 48 amp charging is beyond me, as the cost difference is usually trivial, or at a minimum install a 50 amp circuit using #6 NM-B if conduit or MC cable is something they do not want to use.

Unless running a circuit more than about 150 feet, there is no need to upsize the conductors.

What amazes me is the electricians who run 6/3 NM and then put a 60 amp breaker on. Totally not to code! I had to educate an inspector. This caused the installers to have to come back and remove the 6/3 NM and put in 4/3 NM, which was a LOT LOT more money!!! Like 5K more!
And then when I was paying another electrican to put in my 5 EV charging spots in my garage, he also wanted to run 6/3 NM, and I said nope, not to code since I wanted to hardwire. Instead, yep because I knew the code, he installed # 6 thhn in MC, 90C wiring, which is good for 75 amps! At first he put in 14-50 plugs and I made him put in 50 amps to be in code. I am now putting in the Gen 3's, and putting the 60 amp breakers in, still to code. And I even have a set of 70 amp breakers ready if needed. With all these changes, because I did the wiring right at the beginning, everything stays to code. So simple!! I have a 200 amp sub panel running all these breakers. Will probably do sharing at 100 amps just to not have issues since my heat pumps are on the same circuit.

 

[Rocky_H]

Instead, yep because I knew the code, he installed # 6 thhn in MC, 90C wiring, which is good for 75 amps!

What you have is proper for your 60A circuits, but you need to stop repeating this misinformation on the forum that it's 75A. You always have to follow the lowest limit of any part of the chain of components. Residential breakers are never rated for 90 degrees C, so you don't get to use that rating column. They are up to 75 degree C only, so the rating of your 6 gauge MC cable has to be 65A, not 75A.

Cerrowire Resources - Ampacity Charts

Ampacity is the maximum current that a conductor can carry continuously under the conditions of use without exceeding its temperature rating. Cerrowire's ampacity chart helps calculate the load requirement for a circuit.

www.cerrowire.com

 

[h2ofun]

What you have is proper for your 60A circuits, but you need to stop repeating this misinformation on the forum that it's 75A. You always have to follow the lowest limit of any part of the chain of components. Residential breakers are never rated for 90 degrees C, so you don't get to use that rating column. They are up to 75 degree C only, so the rating of your 6 gauge MC cable has to be 65A, not 75A.

Cerrowire Resources - Ampacity Charts

Ampacity is the maximum current that a conductor can carry continuously under the conditions of use without exceeding its temperature rating. Cerrowire's ampacity chart helps calculate the load requirement for a circuit.

www.cerrowire.com

True, but if folks think doing 60 amps with #6 NM is okay, I guess I would be fine also with a 70 amp breaker in my setup?