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I want to get tesla wall connector installed. I got quotes from 2 electricians and they are suggesting different approaches. I would like to understand who is correct.

I have a 60 amp sub panel in the garage that powers the whole house except AC. The tesla wall connector needs to be installed in the garage as well.

One electrician suggested that the wall connector be attached to the same sub panel ($1200 quote). Another one suggested that connecting to existing sub panel will overload it and it would be better to get a separate 60 AMP connection from the main panel from the other side of the house ($3000 quote)

I would like the fastest charging option possible. who is correct?

the sub panel in the garage

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  • the second one, do not know about the price
    – Traveler
    Oct 19, 2022 at 5:25
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    I noticed it’s a 32 space panel. I’ve not ever heard of a panel that large being rated for 60A. Based on the strangeness, I feel like we don’t have enough information to answer your question. We need to see a photo of the full subpanel and a photo of the full main panel. We also need to know the conductor material and gauge that’s feeding the subpanel from the main. Oct 19, 2022 at 5:42
  • Is this a pic of the main or the sub panel? Please include a picture of the other one, too, and identify which is which. You can edit it into your question.
    – FreeMan
    Oct 19, 2022 at 11:30
  • Can you post photos of the main service equipment please? Oct 19, 2022 at 11:42
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    Yes, since. you now say it's a new-build house, your description of the subpanel makes NO sense and is downright bizarre. We need photos of all the other electrical panels with labeling. Also if you can find exposed cable that runs to this subpanel and get the numbers off it, that'd be good. Cannot imagine a builder using 55A wire for a feeder - 90A wire is cheaper and they know that. Oct 19, 2022 at 19:16

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First, you really need to watch this snippet of this video starting at 28:13 and listen to this person's real experience.

And if the numbers start to be annoying I want you to skip to 34:44.

Really. You do not need the amount of power you think you do. You do not need to charge at 30-35 miles per hour. You do not need to recoup 240-270 miles in an 8 hour night.

And I would be remiss to not tell you that. Somehow "I need the fastest charge" is a "brain worm" that gets into the heads of so many prospective EV owners and costs them A LOT of money -- or worse, deters them from getting an EV altogether.

If it were me

If it were me, I would do exactly what Alec says at 34:44 and install a 20A circuit right in that garage subpanel. Hardwire it straight into the EVSE (to avoid the costly socket, plug and GFCI breaker) using that yellow stuff (or steel jacketed equivalent for use in a garage).

Here's why. This is obviously a modern re-wire of an older all-gas house that had a 60A service. That subpanel is fed by 60A, and it uses most of that. It doesn't have 60A to spare obviously. However my intuition is that as long as you aren't charging while making Thanksgiving dinner, you could probably snake a 20A circuit in there. Easy and done.

Well over 100 miles in a charging night.

In the rare time you need more, Supercharger. Hypothetically let's say you had a 250 mile day and you'll have another one tomorrow. You stop on the way home at a Supercharger and let it charge up to 70-75%. That way you're charging in the fast midrange of the battery pack. By the time you're done walking to get a pastry from Panera Bread or Starbucks or whatever's in the mall, it's at 70-75% and go home. The last 30% happens while you sleep.

Given that this might happen 1-2 times a year at most, and saved you 2 grand of real money, that's not so bad, is it? Enjoy the pastry.

"But wait. Isn't the Tesla Wall Connector a 60A charger?" No, it's an any rate charger. During the commissioning procedure you program the breaker size, anything from 15-60 amps. That's a nice thing about Tesla's units. If you ever change your mind and wire it into a bigger circuit, just run the Commissioning Procedure again. (it's intentionally hard, as a UL requirement to keep people from tweaking it on the fly).

I foresee problems with going for absolute max.

Here's the problem. Your house was originally wired with 60A service. The Square D "QO" panel is a recent modernization of your original 60A panel (and I'm a bit suspicious that ALL your circuits are 20A, unless you did a TOTAL rewire). The service was upgraded to accommodate an A/C unit, and I bet the upgrade was to 100A. To tack 60A more on that, would assume the whole house only uses 40A, and I bet the A/C alone uses that. Well, you can see where that's not gonna fit.

So this seems like fantasy thinking, honestly.

So I think the electricians are hoping to move you into a 200A service "heavy-up". I think they are both bait-and-switching you (or not understanding what they are looking at - the building boom has drawn a lot of incompetent hacks out of the woodwork unfortunately.)

One electrician suggested that the wall connector be attached to the same sub panel ($1200 quote)

That guy is either going to commission it for 20A and not tell you so (exactly what I'd do willingly)... or will say "Hey, found a problem" and will bait-n-switch you into significant wiring upgrades.

Another one suggested that connecting to existing sub panel will overload it

Correct, if you insist on 60A

and it would be better to get a separate 60 AMP connection from the main panel from the other side of the house ($3000 quote)

But then you need a disconnect switch in the garage.

That person too will find your service is only 100A and can't support an additional 60A of load. Another bait and switch, this time to a 200A "heavy-up" with new meter pan, weatherhead, main outdoor mini-panel, weatherhead, etc. etc. - probably $2000-3000 on work on top of what was quoted. And possibly a main feeder upgrade to that 32A.

And man - hauling 60A wires the length of the house is nuts. Better off enlarging the 60A feeder to the 32-space panel to more like 120A, and then sticking the 60A EV breaker in there. 120A is #1/0 aluminum which is much cheaper than 60A wire, because 120A aluminum wire is considered safe, and 60A aluminum wire not so much.


None of them will mention what Alec says in the video. There's no money in that! Fleecing dumb EV owners is way too profitable, so they'll keep prodding you to spend unlimited funds on the fastest charging possible.

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  • $2-3000... Ha! I just got a quote of >$4000 to install the meter-main outside on new construction, run a feed to my current main panel, split neutral/ground there to make it a sub, and install a new sub panel (that I already bought) in the garage. That doesn't include running a single new circuit anywhere in the house! Of course, YMMV, pricing varies, etc. etc. etc. but just to give a concrete example.
    – FreeMan
    Oct 19, 2022 at 11:52
  • thanks for the response. it is a recently built house not a rewire and has 200 amps coming to the main panel. Oct 19, 2022 at 14:18
  • Here in the UK you can get EV chargers that can work with current transformers to monitor and limit load. Do those not exist on your side of the pond? Oct 19, 2022 at 15:18
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    @IthinkThere4Iam what you’re saying doesn’t make sense. What kind of electrician wires up a new house with 200A service such that the entire house is run from a 60A subpanel? Are any of the electricians quoting you, the same electricians who did the original build? Oct 19, 2022 at 16:36
  • @PeterGreen like with wireless CTs like the Myenergi Zappi? Yeah, they're harder to find here. Not impossible, you can do it with the SPAN panel if you have $8000 to waste. UL may be getting in the way. The US answer to that is largely "slow down the charging" as most of our EVSEs allow charge rate to be set at installation time, and like Alec says, 4KW is more than adequate. Oct 19, 2022 at 19:31

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