Adding a 2nd Tesla home charger and tapping the wires.

[mongo]

No and No and No
1. This is continuous long duration amp draw and that is an 80% rule or 48amp/.80=60 amps
2. Wire must be for 60 amps
3. Plug must be be for 60 amps
4. Torque wire screw and hold torque for 5sec release and in 1/2 hour re torque and re hold.
and
You can not series wire amps.
Correction
You can series wire amps but you must double the amp design.
and
That was your original question can I series wire an EV charge circuit and use the existing wires and plugs (which what you have is no per code and could cause fire)
Be Safe
Put in one of those 5 year battery operated smoke detector in your charge area.

Tesla Wall Connectors can be set from 12A to 48A charge current (15A to 60A breaker/ circuit). OP's charge limit is 40A on a 50A circuit.

Group power management allows safely sharing a circuit. Two can share an arbitrarily sized circuit.

No plugs allowed with Tesla Wall Connectors

Yes on proper torque for 5 seconds, but where are you getting the retorque step from?

NM-B is code approved, unless disallowed by local authority.

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[That Beast Mode]

It seems I've caused a lot of debate with my question. From the research I've been doing so far, it seems like I can tap off the existing line and let the Tesla chargers handle the division of power between the two, this is my preferred choice. I can have the electrician run another line from the panel for a second charger, but I like the idea of both of them running on one line so I'm not drawing more than 40A at any given time. I believe my house is 200A service and I don't want to stress that limit either. Like I mentioned before, being able to charge both cars at max speed is not a concern of mine. I am fine with them splitting power or diverting it where needed and charging slower.

 

[JerseyMike]

I have a question about adding a second charger that maybe some of you might know the answer to for me - and before you jump on me, I am not planning on doing this myself, I'll have a licensed electrician confirm and do the work, I just don't want to sound stupid when I am discussing what I want with them.

I have Romex wire in my garage on a 50A breaker currently for my Tesla wall charger. I want to install a second wall charger outside the garage. Can the electrician tap off the existing wires to run a line for the second charger? I want to be able to plug both cars in at the same time - I don't think they would be able to both charge at the same time and that's fine with me.

If this is possible, do the Tesla chargers handle which one gets charged? Does it half and split the power and charge both with this method? I don't want to overload the wires obviously. The install is way easier than getting another run installed from the breaker in the basement to the garage. I know the better way is to have dedicated lines to the panel for both chargers so they can run at full capacity when needed, but I never have a circumstance where I need to charge both at the same time. It's always one or the other but I'd like to not keep having play musical chargers and just add a second one. Thanks.

can easily setup Powershare (that is what tesla calls it) between v2 and v3 wall chargers.

I have 3 chargers on 1 60amp breaker (6 guage wiring so I set it to 44amps total)

if charging one vehicle the full 44amps goes to it, if 2 then 22 amps each, if 3 then 14.7amps each. the beauty of it is that the charger then ramps up when one vehicle is done charging.
You can set this up yourself in an application/url for the wall charger. One will be the master and the second the slave device.

In terms of wiring, the v2 devices can simply splice a splitter in and run the wires to each but with v3 the manual specifies adding a subpanel. I have v3 and my electricion wanted to split them despite that so I ended up saving money and adding the subpanel myself and getting permits and inspection myself....it was very easy and saved me about $1000.

I simply removed the one wall charger and replaced it with a subpanel...then I ran a 60amp breaker from the subpanel with wiring to each charger and used metal clad 6 guage wiring making it super easy.....I added one charger outside and one in the other garage bay.....now I can park anywhere and still charge.

 

[Ivessm]

The suggestion for 6/2 MC {Metal Clad} writing is right on. Easy one-step install. Writing is better than Romex. Coupled with a60 amp double pole breaker you get the maximum 48 amp for charging.

NO PLUGS!! ALL HARD WIRED.

 

[That Beast Mode]

can easily setup Powershare (that is what tesla calls it) between v2 and v3 wall chargers.

I have 3 chargers on 1 60amp breaker (6 guage wiring so I set it to 44amps total)

if charging one vehicle the full 44amps goes to it, if 2 then 22 amps each, if 3 then 14.7amps each. the beauty of it is that the charger then ramps up when one vehicle is done charging.
You can set this up yourself in an application/url for the wall charger. One will be the master and the second the slave device.

In terms of wiring, the v2 devices can simply splice a splitter in and run the wires to each but with v3 the manual specifies adding a subpanel. I have v3 and my electricion wanted to split them despite that so I ended up saving money and adding the subpanel myself and getting permits and inspection myself....it was very easy and saved me about $1000.

I simply removed the one wall charger and replaced it with a subpanel...then I ran a 60amp breaker from the subpanel with wiring to each charger and used metal clad 6 guage wiring making it super easy.....I added one charger outside and one in the other garage bay.....now I can park anywhere and still charge.

So for the sub panel you added, let me see if I understand your setup correctly. You had wires coming from your panel to garage that was originally powering the WC, you removed the WC and now those wires coming from the panel go to a sub-panel. From the sub, you have a single 60A breaker feeding both chargers, or do you have two 60A breakers, one for each charger in the sub-panel? Is there a benefit of doing this over just tapping them? If you have 2 breakers in the sub-panel one for each charger then I suppose it's extra redundancy just in case.

 

[JerseyMike]

So for the sub panel you added, let me see if I understand your setup correctly. You had wires coming from your panel to garage that was originally powering the WC, you removed the WC and now those wires coming from the panel go to a sub-panel. From the sub, you have a single 60A breaker feeding both chargers, or do you have two 60A breakers, one for each charger in the sub-panel? Is there a benefit of doing this over just tapping them? If you have 2 breakers in the sub-panel one for each charger then I suppose it's extra redundancy just in case.

You have it right except I have 2 (actually 3 now that I added another charger) 60amp breakers in the subpanel……yes it is like a redundancy and also makes it easy to cut power to one charger if needed…..I would have just added a 6 gauge wire splitter but instructions for v3 charger indicate subpanel

 

[rjmcinnis]

can easily setup Powershare (that is what tesla calls it) between v2 and v3 wall chargers.

I have 3 chargers on 1 60amp breaker (6 guage wiring so I set it to 44amps total)

Just want to ask for clarification - You say 6 guage, but not what type? If it's THHN, then you can do 48a. BUT if it's ROMEX, you need to reduce down to 40a, and you should have a 50a breaker.

Only asking because your numbers don't match either standard, and want to make sure you stay safe.

 

[JerseyMike]

Just want to ask for clarification - You say 6 guage, but not what type? If it's THHN, then you can do 48a. BUT if it's ROMEX, you need to reduce down to 40a, and you should have a 50a breaker.

Only asking because your numbers don't match either standard, and want to make sure you stay safe.

Good point

My electrician installed the first wall charger with 6/2 romex and a 60amp which many do for Tesla chargers and set to 48 amps
after calculating things myself I found that it should really be 44 amps max (55 amp wire with 80% continual use).


I then added the sub box and additional chargers and realized that the amperage should be 44amps and reduced it….you are right in that I should drop that 60amp breaker to 50 (they don’t sell 55amp breakers I think)

For the wires from the sub I did it the right way and ran 6/2 MC (https://shopwirenco.com/products/cto_6-2mc?_pos=1&_sid=6afe2562e&_ss=r) which is rated higher than romex

 

[mongo]

Good point

My electrician installed the first wall charger with 6/2 romex and a 60amp which many do for Tesla chargers and set to 48 amps
after calculating things myself I found that it should really be 44 amps max (55 amp wire with 80% continual use).


I then added the sub box and additional chargers and realized that the amperage should be 44amps and reduced it….you are right in that I should drop that 60amp breaker to 50 (they don’t sell 55amp breakers I think)

For the wires from the sub I did it the right way and ran 6/2 MC (https://shopwirenco.com/products/cto_6-2mc?_pos=1&_sid=6afe2562e&_ss=r) which is rated higher than romex

FWIW, NEC allows upsizing the breaker if the exact value doesn't exist. However, one cannot then upside the load based on the breaker. So 50A breaker would be "better", but 60A (and 40A max charging current ) isn't wrong.

 

[rjmcinnis]

Good point

My electrician installed the first wall charger with 6/2 romex and a 60amp which many do for Tesla chargers and set to 48 amps
after calculating things myself I found that it should really be 44 amps max (55 amp wire with 80% continual use).


I then added the sub box and additional chargers and realized that the amperage should be 44amps and reduced it….you are right in that I should drop that 60amp breaker to 50 (they don’t sell 55amp breakers I think)

For the wires from the sub I did it the right way and ran 6/2 MC (https://shopwirenco.com/products/cto_6-2mc?_pos=1&_sid=6afe2562e&_ss=r) which is rated higher than romex

So it reads like you still have the 6/2 romex from the panel to the subpanel? If so, the 60a breaker is not code compliant, and could fail to protect the romex in an overload situation. Is it "probably safe"? Sure, but that exceeds my risk tolerance, since a fire is the potential outcome.

You do you, but I would highly recommend throttling back to 40a, and replacing the 60a with a 50a breaker at both the panel and subpanel.

Or do like me, and have a proper run done right next to the incorrect one because my homebuilder didn't do what I asked lol.

 

[Ivessm]

Rjmcinnis is right. If you want to do it right run 6/2 MC from main panel to sub panel. 60 amp double pole breaker in main & multiple 60 amp double pole breakers in Sub panel feeding your ganged WC's with 1 lead and the rest followers. ALL CABLING being 6/2 MC, NO RECEPTICLES (sp?).

Good luck.

Do it right the first time and you don't have to do it over again. It's always been written NOT to use Romex for wall connector wiring.

 

[JerseyMike]

Rjmcinnis is right. If you want to do it right run 6/2 MC from main panel to sub panel. 60 amp double pole breaker in main & multiple 60 amp double pole breakers in Sub panel feeding your ganged WC's with 1 lead and the rest followers. ALL CABLING being 6/2 MC, NO RECEPTICLES (sp?).

Good luck.

Do it right the first time and you don't have to do it over again. It's always been written NOT to use Romex for wall connector wiring.

Good points, not sure why my electrician did the 6/2 romex, I did question it but he said it was fine, also why my town approved it…..I may switch it out to 4 or 3 so that I can run a higher total amperage with PowerShare

 

[hemiarch]

Sub panel, then get 2 50 amp breakers install in your garage. Run new line to your original charger and a new line to your new charger.
Set up load share on the master charger. Add the slave charger. All done in the Tesla one app.
NOTE: UWC setup on the Tesla power share to back up your house DOES NOT allow load share.
I have 2 WC setup for load share and 1 UWC for power share. 2 different circuits, UWC all by its self, load share split from sub panel.
easy pezzy lemon squeezy

So
I currently have a UWC and a Gen 3 connector on the same 60amp circuit on a panel backed up by powerwall 3 and solar. The UWC is the master and the Gen 3 on the other side of the garage is the slave .
Does what you’re saying mean I won’t be able to PowerShare with this setup even after the software is out to support PowerShare with powerwall 3 because of the daisy chain?

 

[smcnaughton829]

So
I currently have a UWC and a Gen 3 connector on the same 50amp circuit on a panel backed up by powerwall 3 and solar. The UWC is the master and the Gen 3 on the other side of the garage is the slave .
Does what you’re saying mean I won’t be able to PowerShare with this setup even after the software is out to support PowerShare with powerwall 3 because of the daisy chain?

Unless Tesla comes up with a software patch to allow the load share to work with PowerShare I can’t see you being able to have both.
That’s why I have 2 circuits, 1 just for PowerShare and the other for load share on my 2 WC.
But I can see Tesla fixing this with a simple software patch. Should take them about 2 weeks.

 

[hemiarch]

Unless Tesla comes up with a software patch to allow the load share to work with PowerShare I can’t see you being able to have both.
That’s why I have 2 circuits, 1 just for PowerShare and the other for load share on my 2 WC.
But I can see Tesla fixing this with a simple software patch. Should take them about 2 weeks.

Let’s start with the PowerShare support. lol.
That has certainly taken more than two weeks

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