Per code each piece of electric vehicle service equipment (EVSE), i.e. the Tesla Gen3 Wall Connector needs to be on a dedicated circuit protected by a breaker.
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Wall charger installation question
- Thread starter tkt546
- Start date
Right. It's because of how there was a change to the capabilities of the sharing and therefore the installation instructions when Tesla switched from the Gen2 to the Gen3 wall connectors.
On the Gen2, you picked the amps for the main circuit, and then all of them had to be wired for that--same wire thickness and everything, so it allowed just attaching the wires together with Polaris connectors or equivalent, because you knew they had to be matched.
With the Gen3, they allowed the capability that you could install and configure the amps individually for each one. So they were not all guaranteed to be on the same sized circuit. So a business could have a bank of 8 units, and maybe 4 of them were set for 60A and the other 4 for 30A (but all still sharing the capacity of one main feeder line). They could use smaller wires to the 30A ones, but then those do need to be protected with smaller 30A breakers to each.
So that's just how the new installation instructions are--that you need to run your main line into a subpanel, and then use breakers to split out to each one.
Midnightsun
Active Member
Ideally just install another 60a breaker in your panel and run another 6/2 to the second wall charger. Installing a sub panel and breakers is going to cost quit a bit more than an additional 55' run of wire and a single 60a breaker.
dgbehrends
Member
Unfortunately this is not the case. My main panel is only 150amp and is now completely full. I was quoted several thousand dollars to put in a 200amp panel since that is what the service line supports. The cost of the wire to make another run out to the garage is expensive at around $250. I have enough wire left over from the current install to put in the small sub panel and the short routes to the gen3 chargers. The 60amp breakers are $15 a piece through Graybar.
It sucks that I can no longer run both gen3 off of the same circuit when they are designed to power share. Adding the sub panel and the extra 60 amp breakers only to run to another 60 amp breaker at the main panel doesn't seem to be much better.
Huh? It IS power sharing from the same main circuit. Why do people insist on not seeing it that way?
You DON'T have to add another 60A breaker at the main panel. Where are you getting this from?
I described all of this earlier. It's ONE 60A breaker in your main panel. You do all of that long wiring run to your garage with that ONE circuit. Then in your garage, you put the subpanel. The subpanel is running two 60A breakers on the one 60A feeder circuit, because the two units are sharing. The two breakers are basically just a connection method instead of wire nuts or Polaris connectors. It's still just one main 60A circuit supplying the power.
Midnightsun
Active Member
When you say full, I assume there are no more places to install another 60A breaker? A new sub panel is going to cost at least $100 plus installation. Any way you can install a couple of tandem breakers to free up some space for another 60a breaker in the main panel?
You will be running both off of the same circuit in the end. You are supplying the sub panel with a 60A breaker which in turn will power both the wall connectors via 2 60a breakers from that one circuit albeit at a maximum of 48a total draw due to power sharing. Sounds pretty dumb but I guess thats they way it is written which many times makes little sense.
Regardless of which way you choose in the end, you will be power sharing. I have a similar setup with a 100A feed to the sub panel however I do have a 40A spa circuit on the same panel and a 15a circuit for the garage door opener. Dual 60A breakers run to 2 wall connector which I have set up to power share. In my case I set the max to 50A between the 2 and so far so good.
dgbehrends
Member
Yes the main panel has all slots full. I will be installing a couple of tandem breakers for my basement finish. I don't dare allow my garage to draw more amps otherwise I might flip my main if I am running the dryer, air-conditioning, stove and gen3 charger at the same time.
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davewill
Active Member
You wouldn't be allowing the garage to draw more current. That's what power sharing is all about. Adding the second 60a breaker doesn't mean that you have to have another 60a of capacity. Whether you do the subpanel, or add the second 60a to the main, it's the same thing in the end. Personally, I'd do the subpanel because it's convenient to have a shutoff right there in the garage and to avoid the hassle of doing the long run of wire.
dgbehrends
Member
Correct, it "doesn't mean that I have to have another 60a of capacity", but the capability would be there and at some point someone might try to use it and flip the main. It's not the end of the world as that's what the main breaker is for but not good for any computer devices that happen to be running. I'll just add a small subpanel with the two 60 amp breakers whenever I get a second electric car. Running the the 6/3 MC was a pita according to the electrician. Running another one would probably be easier but still a lot of money for the copper in that wire when the subpanel will work just fine.
That’s what I did. I ran #1 SER from my main to the garage. And I’m putting a 100amp sub panel in the garage. And a 60amp breaker in the sub panel. It’s costing me a bit more but I’m a contractor and my electrician will do this super cheap. I am at around $500 in wire, conduit(in garage only) and breakers. I ran the SER myself and did the conduit pulled the #1 through it. Now I will benefit from a sub panel in the garage and a short 2’ or less run of copper 6/3 MC from sub panel to the wall charger.
No! That's not true! We have explained this several times.
The circuit sharing DOES WORK! Putting in the subpanel and putting in a 60A breaker for each of the two wall connectors DOES NOT mean they can ever pull that full amount on both at the same time. The circuit sharing does not ever allow that to happen, as you are mistakenly stating.
One single 60A in the main panel. That is your one single supply limit. When you then put two breakers in the subpanel, you configure the two wall connectors to tell them what the total upstream capacity is. It will not run double that amount of current and trip your main breaker in the main panel.
You could put in one single 60A supply line feeding a subpanel with 16 wall connectors, each with 60A breakers, but you set the circuit sharing to tell them that the total supply is that 60A circuit, and they will not go over that as a whole added together.
I am sorry if I am sounding frustrated at this point, but we have explained the circuit sharing multiple times, and you continue to act as if it does not do anything at all, which I really don't get.
davewill
Active Member
I think he's worried that some future owner of the house might try to use both circuits without circuit sharing and blow the main house breaker, which, I grant, using a subpanel might avoid.
dgbehrends
Member
davewill you are right. Thanks for clarifying this for Rocky_H. I understand things perfectly as I was referring to the post before about having two 60 amp breakers in my main panel for two unique circuits running to the garage.
Ah. I thought that had already been rejected and wasn't being considered, because you said you knew you didn't have the capacity to do that, so that wasn't what we were talking about.
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