Tesla Universal Wall Charger And Mobile Charger On The Same Circuit?

[davenlei]

Here is my current setup:
I have a Model Y I have been using the mobile charger that came with the car (2021) to charge the car on a 14-50 NEMA 60A circuit I had installed back in 2021. I believe 4GA wire was installed since I requested it from the electrician. The length of wire from the breaker to the plug is about 2-3 feet since the plug is on the opposite side of the same wall the breaker is on.

Now here is what I am needing:
I recently bought a Model X and want to charge it overnight also. I also purchased one of the new Tesla Universal wall chargers. I know if you daisy chain wall chargers on the same circuit, they will communicate with each other and load balance to not overload the circuit. Since I am running a mobile charger and now want to also run a wall charger, will the wall charger sense the load of the mobile connector on the same circuit and reduce it's draw to not overload the circuit or will I need to install a separate dedicated circuit for the wall charger?

I plan to get another wall charger in the future to have them communicate and balance the load but did not want to incur that additional equipment expense or the expense of installing another circuit right now if the 'line sharing' option between a mobile charger and wall charger I described above would work.

 

[E90alex]

No, you cannot do that.

The wall connector power sharing doesn’t work by automatically detecting load on the line. It has to be manually set up and the wall connectors need active communication with each other. The wall connector cannot communicate with the mobile connector.

 

[jjrandorin]

I plan to get another wall charger in the future to have them communicate and balance the load but did not want to incur that additional equipment expense or the expense of installing another circuit right now if the 'line sharing' option between a mobile charger and wall charger I described above would work.

It doesnt.

Load sharing requires not only Tesla wall connectors but ones of the same generation. You cant even buy an older Gen 2 wall connector and load share with a Tesla Gen 3 wall connector (which is what the universal wall connector is based on).

 

[davenlei]

No, you cannot do that.

The wall connector power sharing doesn’t work by automatically detecting load on the line. It has to be manually set up and the wall connectors need active communication with each other. The wall connector cannot communicate with the mobile connector.

Ok, good to know. I had a feeling that was the case but wanted to make sure. I do have two more spots on the panel to install another 60A circuit so I guess I will have to go that route.

 

[Supcom]

I'm still wrapping my head around protecting a 14-50 outlet with a 60A breaker. I understand that using it with a mobile connector will not exceed the 14-50 current rating, but isn't it still against the NEC? Did a certified electrician do that?

 

[beatle]

Yeah, a 60A breaker on a 14-50 isn't up to code. Should be a 50A. I wonder if the wiring supports a 60A load (perhaps #6 THHN in conduit?) but the owner wanted to run a UMC temporarily until they replace the 14-50 with a HPWC, and they didn't want to buy a much more expensive 50A GFCI breaker for the 14-50. Still not right, but that would explain the 60A breaker.

 

[Supcom]

Yeah, a 60A breaker on a 14-50 isn't up to code. Should be a 50A. I wonder if the wiring supports a 60A load (perhaps #6 THHN in conduit?) but the owner wanted to run a UMC temporarily until they replace the 14-50 with a HPWC, and they didn't want to buy a much more expensive 50A GFCI breaker for the 14-50. Still not right, but that would explain the 60A breaker.

The OP mentioned 4 ga wire, which should be good for the breaker. If an electrician did the job, it seems that he should have put in a 50A breaker, which would be perfectly fine in this setup and would a simple upgrade when a UWC gets installed.

 

[davenlei]

Actually the electrician installed a 50A breaker but said it was wired with 4GA T90 insulation? (I think that is what it is) and can be swapped out with a 60A breaker when the 14-50 connector is removed and is wired direct to the wall charger when I purchase it. The three black wires are what was installed for the charger.

 

[Eric33432]

Here is my current setup:
I have a Model Y I have been using the mobile charger that came with the car (2021) to charge the car on a 14-50 NEMA 60A circuit I had installed back in 2021. I believe 4GA wire was installed since I requested it from the electrician. The length of wire from the breaker to the plug is about 2-3 feet since the plug is on the opposite side of the same wall the breaker is on.

Now here is what I am needing:
I recently bought a Model X and want to charge it overnight also. I also purchased one of the new Tesla Universal wall chargers. I know if you daisy chain wall chargers on the same circuit, they will communicate with each other and load balance to not overload the circuit. Since I am running a mobile charger and now want to also run a wall charger, will the wall charger sense the load of the mobile connector on the same circuit and reduce it's draw to not overload the circuit or will I need to install a separate dedicated circuit for the wall charger?

I plan to get another wall charger in the future to have them communicate and balance the load but did not want to incur that additional equipment expense or the expense of installing another circuit right now if the 'line sharing' option between a mobile charger and wall charger I described above would work.

As mentioned by others, the load sharing will not work with what you are suggesting.

It is also against the NEC to put an EVSE such as a Tesla Wall Connector on the same circuit as another receptacle, but on top of that it would actually be easier to run new wiring for your wall connector, especially since it is so close to your electrical panel. Splicing the wires to daisy chain two devices would be more difficult and complicated than just running new wiring to another breaker in your panel, and it looks like you may have space for another 2 pole breaker right below the breaker for your 14-50.

 

[davenlei]

As mentioned by others, the load sharing will not work with what you are suggesting.

It is also against the NEC to put an EVSE such as a Tesla Wall Connector on the same circuit as another receptacle, but on top of that it would actually be easier to run new wiring for your wall connector, especially since it is so close to your electrical panel. Splicing the wires to daisy chain two devices would be more difficult and complicated than just running new wiring to another breaker in your panel, and it looks like you may have space for another 2 pole breaker right below the breaker for your 14-50.

Ok, thank you for the advice. Since I have space for another 2 pole breaker I will just have a 60A breaker and new wiring run for that to my wall charger sitting in the box right now. If I wanted that run to go across the garage to the other side (about 25+/- feet), would it still be 4GA copper wiring or does the length change things?

 

[Eric33432]

Ok, thank you for the advice. Since I have space for another 2 pole breaker I will just have a 60A breaker and new wiring run for that to my wall charger sitting in the box right now. If I wanted that run to go across the garage to the other side (about 25+/- feet), would it still be 4GA copper wiring or does the length change things?

If you want to wire a Tesla Wall Connector to a 60 amp circuit, for 48 amp charging, and you want it to be done in accordance with the NEC, your choices are, all copper wire:

#4-3 NM-B cable (Romex) (very hard to work with inside the wall connector because it is so stiff, and only available in three conductor + ground)
#6-2 MC cable (much preferred over NM-B)
#6 THHN/THWN-2 conductors (#10 for ground wire) (must be run in PVC, flexible conduit, or metallic conduit)
#6-2 SEU cable, (might be hard to find)

If you don't want to run in conduit, MC cable, which is often overlooked, is the best way to go. I did exactly that-went from panel on one side of my garage to the other side using #6-2 MC cable. Easy to find on Amazon and other on line sources, not available at big box stores in my area.

 

[IvesSM]

@Eric33432 excellent write-up, excellent advice. I to generally recommend MC cable over conduit for Wall Connectors. The one step install over the 2 step with conduit and THHN is the selling point for me.

 

[Eric33432]

@Eric33432 excellent write-up, excellent advice. I to generally recommend MC cable over conduit for Wall Connectors. The one step install over the 2 step with conduit and THHN is the selling point for me.

Ives, thanks!

I completely agree unless you have an installation such as this one, which my step son and his g.f. share for two M3 Tessies.

First, part of it was outside, and second their conduit run was straight not complicated. I think the conduit looks better than MC. Had it been complicated and had to run inside walls, around obstacles, etc., I would have switched to MC once the circuit was indoors.

Post your Garage charging setup! (pictures, Wall Connector, multi-EV)

Just got our 2nd MY home today. I tucked the wires into the wall to get them out of the way. Hope there aren't any mice in there. I usually have the lawn mower against the wall. It's a little awkward that way. I need to tinker with it a bit more.

teslamotorsclub.com

One of my TWCs in my garage had to run to the other side of the garage, and I ran the cable around where the garage door springs, etc., are located and MC was definitely better in that case, and that is what I used for that.

I find in these discussions about installing circuits for NEMA receptacles or EVSE that MC is often overlooked in the discussions!

 

[terranx]

Yep, we did MC in our garage too. 6/3 to a small sub panel, and from there 6/2 to two Tesla wall connectors.

 

[davenlei]

If you want to wire a Tesla Wall Connector to a 60 amp circuit, for 48 amp charging, and you want it to be done in accordance with the NEC, your choices are, all copper wire:

#4-3 NM-B cable (Romex) (very hard to work with inside the wall connector because it is so stiff, and only available in three conductor + ground)
#6-2 MC cable (much preferred over NM-B)
#6 THHN/THWN-2 conductors (#10 for ground wire) (must be run in PVC, flexible conduit, or metallic conduit)
#6-2 SEU cable, (might be hard to find)

If you don't want to run in conduit, MC cable, which is often overlooked, is the best way to go. I did exactly that-went from panel on one side of my garage to the other side using #6-2 MC cable. Easy to find on Amazon and other on line sources, not available at big box stores in my area.

Thank you very much! Very good information!

 

[Eric33432]

Thank you very much! Very good information!

Another thing I meant to mention is that MC cable can be run exposed on the outside of an interior wall. NM-B must be run inside walls, in the attic, in holes drilled in floor joists in a basement, etc. A short run of Romex, say coming from inside the ceiling, may be run in conduit down the outside of a wall to a receptacle Wall Connector.

 

[davenlei]

Another thing I meant to mention is that MC cable can be run exposed on the outside of an interior wall. NM-B must be run inside walls, in the attic, in holes drilled in floor joists in a basement, etc. A short run of Romex, say coming from inside the ceiling, may be run in conduit down the outside of a wall to a receptacle Wall Connector.

I see your post showing your step son's install with conduit running along the wall. If I have a similar install but with just a couple more bends, is that acceptable to use conduit on the outside of an inner garage wall (like your pics) but with drywall as the stud cover? I am assuming from your comments, it needs to not be NM-B in the conduit (use THHN/THWN).

 

[Eric33432]

I see your post showing your step son's install with conduit running along the wall. If I have a similar install but with just a couple more bends, is that acceptable to use conduit on the outside of an inner garage wall (like your pics) but with drywall as the stud cover? I am assuming from your comments, it needs to not be NM-B in the conduit (use THHN/THWN).

Yes, PVC or metallic conduit can be run exposed along an interior or exterior wall. It does not matter if the wall is sheetrock, concrete block, brick, etc. You should run individual wires, not NM-B or any other cable. Almost all building wire is now rated both THHN and THWN-2. You use the 75˚C column for the ampacity, and the 90˚C column if you need to derate for temperature or number of conductors.

If you use metallic conduit outdoors you must use the fittings designed for wet areas. Generally grey PVC electrical conduit is much easier to deal with.

You should not run NM-B in conduit except where you need to protect it, and installing NM-B exposed can run into problems. Code says if it is run where it is subject to damage it has to be protected, but sometimes people argue about what areas are subject to damage so I avoid running it exposed, with a few exceptions, like running in an unfinished basement through holes drilled in ceiling joists.

And it would be very difficult to pull a long length of NM-B inside a conduit. Short lengths are not too difficult.

In fact, pulling two #6 and one #10 wires in a 3/4"conduit can be difficult, especially if you use the pre-made 90˚ bends; that is why we used conduit bodies for the job for my step-son that you reference, and for the job in my garage, where the run from one side to the other had a lot of bends to snake it around where the garage door rails attached to the wall above the doors I ran MC cable.

Good luck with your install!

 

[davenlei]

Yes, PVC or metallic conduit can be run exposed along an interior or exterior wall. It does not matter if the wall is sheetrock, concrete block, brick, etc. You should run individual wires, not NM-B or any other cable. Almost all building wire is now rated both THHN and THWN-2. You use the 75˚C column for the ampacity, and the 90˚C column if you need to derate for temperature or number of conductors.

If you use metallic conduit outdoors you must use the fittings designed for wet areas. Generally grey PVC electrical conduit is much easier to deal with.

You should not run NM-B in conduit except where you need to protect it, and installing NM-B exposed can run into problems. Code says if it is run where it is subject to damage it has to be protected, but sometimes people argue about what areas are subject to damage so I avoid running it exposed, with a few exceptions, like running in an unfinished basement through holes drilled in ceiling joists.

And it would be very difficult to pull a long length of NM-B inside a conduit. Short lengths are not too difficult.

In fact, pulling two #6 and one #10 wires in a 3/4"conduit can be difficult, especially if you use the pre-made 90˚ bends; that is why we used conduit bodies for the job for my step-son that you reference, and for the job in my garage, where the run from one side to the other had a lot of bends to snake it around where the garage door rails attached to the wall above the doors I ran MC cable.

Good luck with your install!

Again, fantastic detail and information. Thank you so much. I learned a lot today and realize I have a lot more learning to do before I proceed.

 

[IvesSM]

Main things to follow:
1. ALL CABLE RUNS ARE DIRECT POINT-TO-POINT.

2 BREAKER TO WALL CONNECTOR. NOTHING IN BETWEEN.

3. NO J BOXES, BUGS, PLUGS, RECEPTACLES, ETC.

4. ALL CONNECTIONS PROPERLY TORQUED TO SPEC.

5 USE Dielectric Grease SPARINGLY.

That's it.